If you have a distorted, or bent coiled handset cord, that is still in servicable condition, but frankly looks too bad to use. Try what I did.
Take a piece of wooden dowel, or steel rod, 3/8 of an inch in diameter. Find or cut a piece that is about an inch or two longer than the cord is when completely compressed together.
Secure one end of the cord to the dowel or rod, using duct tape. Then coil the cord tightly around the dowel, or rod. Secure the other end with duct tape.
Then secure the ends with tiewraps.
Now run hot water over the coiled cord, dry off with compressed air, or blow the water off, then let set until completely cooled. The coil will now be like new.
If the cord was dirty, you can also clean it before you wrap it around the dowel or rod.
Dan
Nice photo Dan. Nice tip, thank you. I have heard of guys doing that but instead of putting water on them, I have heard of putting the whole thing on the dash board or in the back window of a car while it sits in the sun. I know one collector that put the whole thing inside a black bag and left in the back window of his car (out in California) for several days.
I have also tried reversing the coils. That will tighten up the cord too. I'm going to try your method. Thank you.
Wouldn't a heat gun or blow dryer work? Of course ya gotta watch how hot you get it.
Bdm;
I'm sure many ways will work, I might add that the first time I didn't let the cord stay wrapped long enough.
I'm beginning to think maybe the window idea, may even work better. I'll still say the securing the way I did it should work very well. It's extremely tight around the bar.
Dan/Panther
I read in my internet travels, that somebody used a couple day-heat treatment, and followed that by a couple days in the freezer. After letting it gradually come up to room temp, it's fixed. I've never tried any of these methods, myself.
I clean my cords by throwing them into the dishwasher. :o It really makes them look nice and purty, and they always work afterwards. Learned this from tinkering with computers, you can often put an entire keyboard in the dishwasher and it will come out looking new, let it dry real good and you are good to go.
For a quicker solution:
The cords can actually take fairly high temperatures-I think that WE used temperatures above the boiling point of water. So, you can either boil the cords, or, even better, stick them in an oven at about 220oF.
For a more positive set, you can also rapidly go to a colder temperature. A freezer works well, although lower temperatures won't hurt.
I've had good luck in the past cooking them in a lab oven at about 110oC, followed by dropping them in liquid nitrogen(-196oC). Should you go this route, the only problem is that the rubber is brittle at temperatures that low, so the insulation on inner wires can crack. They're fine when they warm back up, although cracks are permanent.
Ben, what is the long-term effect? Will they maintain elasticity and retract normally when used after the "procedure"?
Dennis,
I only did two that way, but they're both still fine.
I've read that rapid temperature changes were how Western Electric originally set the cord, so doing the same restores them to their original condition.
Here are the results, of the cord two days on the rod, in the sun, one day in the freezer.
The sun did work better than hot water. If the cord had been in the hot water longer it may have worked as well, but the sun method seems safer.
D/P
With the black cord it may not matter, but with a colored cord, the idea of putting it inside a black cloth bag will eliminate further fading from sunlight. It won't be long here in Michigan when the sun won't produce enough heat---but freezing won't be a problem. :)
I forgot to mention one item.
Before I removed the cord from the dowel, but after it had completely thawed and dried, I sprayed it with "Sun of a Gun", an Armoral type product. I let that soak in for awhile then wiped it with a clean rag.
D/P
That's what I normally do. If the cord is especially grungy, I let it soak in Simple Green, keeping both ends out of the cleaning fluid. Then wipe it down, carefully pulling through the coil. Then an application of armor all. Looks almost new in the end.
Another product that a friend swears by is made by Turtle Wax. It has an added UV protection ingredient. He puts an application on the handset and line cords after they've been cleaned. He also applies it (as a polish) after polishing with Novus2. It will help from being discolored from future light exposure.
What is the preferred method for cleaning a handset cord while it's still attached to the phone? I was planning on using Armor-All wipes.
EDIT: Doh! I just realized that there was a second page to this thread that answers my question!
OK guys, I'm giving this a try. I've never tried to tighten a cord. I've read your postings a couple of times. I'm using the oven method as opposed to hot water.
I have a wall phone cord (model 554 from October of 1964) that I want to reuse. It is a nice cord except it is a bit stretched at each end. Because I can't throw ANYTHING away I have lots of stretched-out cords. So I'm starting with one of those.
For my example I am using a very long stretched red handset cord. I'm sure it was originally on a wall phone. I'm guessing that the phone may have been in some type of automotive environment as it was very greasy and stretched. I'm guessing that it was stretched to six or seven feet.
I bought a 3/8th inch wooden dowel for this experiment. I took the red handset cord and soaked it in warm soapy water for about 45 minutes. I drained the water off and then used a 409 type cleaner and a rag to clean each coil. It's nice and clean. I then wrapped the cord tight on the dowel and fastened each end per Dan/Panther's instructions. To keep it off the floor of the oven, or from touching the walls of the oven I took two small pieces of wood (cut off the end of a 2X4 and cut in half again) and drilled holes in each, just larger than the 3/8 inch dowel.
The dowel is almost too long to fit in the oven. So my experiment nearly ended before I started. But I was able to kind of put it in the oven on an angle with one jammed up tight near the roof of the oven. Before placing it in the oven I wrapped the four leads on each end with foil to keep them from touching anything. Whether or not it will protect them we will see.
I have the oven set at about 225 degrees. It's baking now. In a few hours I'll take it out and put it on the back porch. Since our temps are going to be zero tonight (currently about ten degrees above) that ought to be better than sticking it in the freezer.
More to come...................
I'd like to try it too but would it not melt inside the oven?
It's been in the oven now for about two hours. I can smell the plastic but it doesn't appear to be melting. In another 20 minutes it's headed out into the cold Michigan winter night.
Part One of this "experiment" is concluded. I may have rushed things a bit but I had to see if I was wasting my time with this cord. There are couple of factors about this cord that made it probably not the best choice for my first experiment. The first is the length of the cord. This cord, tightly coiled is a long cord. They tend to "hang long" when on the handset and the handset is in the cradle of the 554. It's a heavy cord. Secondly it was in the poorest of condition. Not only was it stretched but the cord had stiffened. I could almost stand it up in the corner! (Bad cord!) :)
After two hours in the oven at about 230 degrees it sat outside for 13 hours in near zero temperatures. I brought it in this morning and used my trusty hair dryer to warm it before trying to remove it from the dowel. (I love that hair dryer!) The faint odor I was smelling last night I think was the tape not the cord. There was no evidence of any damage to the cord as a result of the heat. The cord was stuck to the dowel in that I had to run my finger nail from one end to the next....like a needle in the groove of a record (you old people like me relate to this) to get the cord off without pulling it off the stick.
Result: The cord was no longer stiff. The coils maintained their original shape. However they are NOT tight enough. The cord is usable but as I held it up to my 554 holding one end where it would attach to the phone and the other where it would attach to the handset there was some sag, or stretching. However it didn't hang as low as the cord on my wall phone. That cord when installed was new old stock and it's been hanging there for a year or so. So gravity is going to work on that.
Conclusion: Would I be satisfied with that cord on a nice soft plastic wall phone? No. Is it much improved from when the little experiment began? Yes. I would say it is 75% improved. In a desk set situation where the cord lays on the table when not in use it may all for the repaired cord to be usable.
I am not going to give up on this cord yet. I'd like to give it another shot but maybe this time use the hot water treatment on it. Also I am in the process of doing a second cord. This time I'm using a black handset cord which is the normal desk set length. It is stretched but nothing like this red one. I'll use a shorter dowel and bake it a bit longer and then it will be outside to watch the snow fall.
I'm attaching a photo of the cord after being removed from the dowel and after I manhandled it a bit. I'm going to put the first photo on again so it is easier to compare the two. We may be onto something here. I know it's nothing that hasn't been done before. But I've always looked for replacement cords which is great if you can get one but this may be helpful. By the way, the red cord has a date of 1975 on the strain relief hook.
I think that's a great set of posts, Dennis. Well explained and well photographed. The thing I find most interesting is that the process cured the cord of it's stiffness. That can come in very handy even for cords that are not stretched or kinked, but which have just grown stiff over time.
Bingster, thank you for the compliment on my "experiment". Good point on the stiffness issue. I have been working on the red cord again. I put it back on the stick and strapped it down tightly. This time I had the tea kettle and a large pot boiling water at the same time. I must have filled up each about 4-6 times and poured the water slower over the coils. I had the ends of the stick on each side of the kitchen sink with the cord coils suspended so there would be no flat spots. I gave that cord a good soaking with the boiling water and now it's out in the cold again. We'll see if it improves any.
Meanwhile I did a shorter cord from a model 500. This one was stretched and a bit stiff. I washed it like before, then wiped each individual coil using 409 cleaner to make it nice and clean. In the oven between 225 & 250 degrees for several hours. In fact I had it in the oven for about an hour and a half and had to leave. So I turned off the oven and turned it back on again when I returned and left it in there for another 3 hours. It's outside enjoying the frigid cold now. Supposed to go down to -3 tonight. We shall see how that one turns out. I am more optimistic in that it wasn't as stretched and it's shorter. It's from 1959.
My wife looked at the red cord before and after and said, and I quote, "Wow, it's like a miracle."
So I think you are doing pretty good work. I assume that the plastic is reflowing to some degree in the heat, and then being reset, do you know how they made these cords? (or still make them?)
I've done the second test on the red cord and did a black one as well. First I will talk about the red one and show a couple of photos. I will post results of the black in a separate posting so I can put on more photos.
I think that the condition of the red cord improved somewhat. The cord is useable but again, since it is a wall phone cord as it hangs it is going to stretch. Gravity is stronger than the strength of the coils. Overall, I would increase the total improvement to 85%...maybe even 100% because before the cord was completely unusable. The cord is now soft and pliable.
This time I poured boiling water over the cord while it was on the dowel. A LOT of boiling water. Would it have been better had it been able to soak in the water? Perhaps. I was thinking maybe a wall paper tray or something like that will work for soaking in boiling water or just below the boiling temperature. The wallpaper trays I've seen were plastic so I don't know if they would support boiling water. Just a thought.
After the water treatment it went outside for 24 hours. Our morning temperature was below zero this morning so I guess that's cold enough. A regular home freezer? Maybe keep it in there longer. What is long enough?
I took the second batch of photos after the cord had warmed to room temperature. This cord is date stamped 1974.
I don't know if these second set of photos will show much more than the first "after" photos.
Now the black cord. This cord is dated 1959. It too was very stiff and stretched. I put it on a shorter dowel and was able to fit it comfortably in the oven. Again, I used little blocks with holes drilled to fit over the dowel at each end. It kept the dowel suspended above the floor of the oven rack. I put a couple of sheet pans down first so the blocks wouldn't fall through the grate.
I baked the cord for a longer period of time...probably all together 3-4 hours at 250 degrees. Then it went out in near zero temperature for about 14 hours. Some of that time the temperature was below zero.
The plastic seems different than that of the cord from 1974. It is more sticky. Long after it had warmed to room temperature I removed it from the dowel. The coils stayed together and as the red one, it is soft and pliable.
I simulated conversation by holding each end the approximate distance one would stretch a cord from a desk phone to the ear and held it for a period of time, maybe a minute. The cord did not immediately retract. My photos will show the cord just off the dowel, immediately after simulated use and then a minute or two later as the coils kind of crept back together again. If I "help" it, it will retract completely.
So once again it is usable where before it was not. As the collectors like to say, "It Presents Well". I have no immediate plans to do this one again use the water technique but may eventually (I've got other things to do!) do that.
I think that in summation these techniques will greatly improve the condition of a useless, stiff and stretched cord, especially for display purposes.
I think the differences in plastic technology from 1959 to 1974 is evident in the feel of the cord.
Let me know if there are questions. I may have omitted something.
I think it may be worth doing for a cord not easily replaced, or when wanting to keep a phone all original. they look in the pictures, to be much improved. with the red one, it looks like it should get tossed out in the before pics, but I think it looks usable in the after. not a new cord by any means, but very presentable. thanks for sharing the photos, I have an original black cord on a 57 desk I may try this on. it is still in fairly good shape, but may give better results as it's in better shape to start with.
Dennis;
I would say both of the experimenrts were successful.
They both appear as N.O.S.
D/P
Thanks Dan. They are much improved for sure. That black cord is 50 years old this year! A half a century! I'll bet the person(s) that made that cord never dreamed that someone in the 21st Century would be trying to make it look new again and posting pictures on the internet! :)
Now how about straight handset cords that curl up? I have a vintage 302 with a straight rubber cord that thinks its a rattlesnake. Should I just boil it and hang it out in the cold off a hook with handset attched? ???
Quote from: Sargeguy on January 18, 2009, 12:47:39 AM
Now how about straight handset cords that curl up? I have a vintage 302 with a straight rubber cord that thinks its a rattlesnake. Should I just boil it and hang it out in the cold off a hook with handset attched? ???
On straight cords I fastened them to a board by the strain reliefs, rather tightly. let them cool that way, and they stayed straight or if I coiled them up they would remain subtle, without twisting. I make a loop of the cord when I hang up, and try to hang them up the same each time. This prevents the kinking from years of twisting.
Periodically I will hang the handset at length, to let it reach it's own comfort zone. this take out the minor twists.
D/P
Thanks! I boiled it for a few then let it hang outside from the strain relief with the handset on the other end. It's not exactly supple but at least its straight.
Spray it with "Armoral", "Son Of A Gun" or a like product, may soften it up a bit.
D/P
Greg, in my experiment(s) I didn't actually boil the cords but poured boiling water over them while they were on the dowel.
I'm cooking a distorted black 1960 handset cord right now in an attempt to get it back to some springiness. Here it is in the oven:
Heath, I didn't think to suspend it from above. Good idea. I did another one a few days ago and didn't get real good results. But I'm going to give it a shot again....before it warms up too much outside. Let us know how that one turns out, please.
Best luck I've had so far was the dashboard/freezer method.
Wrapped aropund a dowel, placed on dashboard for a week, put in freezer overnight. However that is pretty much a summer system.
D/P
Okay here is a picture of the finished cord. It came out quite well and it looks good. The coils are much tighter and it retracts, albeit slowly. Since it's for a lightly used desk phone this was a great fix, and I think it will be successful on a couple of other distorted cords I have. Wonder if it would work on modular cords?
Heath, how long did you bake it? What temp? Then the freezer??
Bake at 250 degrees for 2 hours.
Place in freezer for 4 hours.
Allow to adjust to room temperature, 1 hour.
Serves one.
:)
Well, I gave this a shot myself. I had picked up a new desk cord for my WE500, but felt that the cord was a bit too hard, and a bit short at my desk. The old one was decent, but had some stretched spots and one or two reverse twists. I let it sit for about three hours at 250 and will bring it in tomorrow. It's snowing right now so I have it inside a length of PVC pipe.
We shall see, this is a newer cord with a 71 date stamp.
Well, after digging the cord out of a foot of snow, I unwrapped the cord and it looks great! (Wish I had remembered how much of that cord protector stuck out of the head set. I have a zip-tie mark on it now) :-\
Oddly though, I have some light static on the line now?? Any thoughts? It might just be the lines, we did get a foot of snow today... ???
If your cord's internal wires are wet or have moisture I would think it could produce static. I'm thinking more in line with your foot of snow and some external static. Try a different phone if you have one. If it's your cord, just let it dry out good.
Better you than us (snow). For once we dodged the bullet here in Michigan.
Well I found the problem, I had re-wired my phone system this weekend with new boxes and that new flush mount wall outlet I picked up. I have DSL internet, so filters are needed on the phone lines. Although I had a filter in the DSL line with one end going to my fax and the other to my cordless phone, the Bell phone was picking up feed back from the DSL. I just added some more filters and the line has cleared up now.
Here is how the cord came out. It was not too badly stretched, but the ends were a bit rough and there were a few reverse twists that would not "un-twist" without looking messed up. So far with a full day's use, it is holding up well and is long enough to not have to be pulled. The replacement cord was a bit too short for my desk (it's 36" deep) Now I can use the phone without moving the phone closer to me.
Now my phone cord was not "shot" but it fixed the messed up coils 100% and the cord looks new now so I am very happy!
(http://www.yankeetoys.org/lee/32093.jpg)
Thanks guys, I appreciate the post as I would not of thought of doing this myself. This cord is perfect at my desk both in length and elasticity. In fact I am on hold with the phone tucked on my shoulder as I type)
The phone is a 1958 and "might" of been tan once. The dial has a marking that listed it as being tan, but all the phone internals have matching numbers. The cord is a 72 and the headset innards are 60 & 61 so who knows. The dial could be a red hearing, but with everything number matching, I would be supprised that they put a used dial into the phone, changed the ring to black, and matched down to the month!
It is in wonderful shape and just a mild cleaning with Simichrome was done. As I have posted before, the best part is the original thick cord and 4-prong bakelite plug that was on it. I paid about $20.00 for the phone on e-bay.
Tonight I came upon a PDF file documenting how these cords are manufactured. I thought it would be a good addition to this thread.
The most telling paragraph is at the bottom of the first page:
QuoteFinally, the cords are tightly wound on a steel rod and baked for 8 minutes in an oven at 268 degrees Fahrenheit to permanently set their coiled shape. Additional spring comes when the coils are re-wound in the opposite direction, causing internal stresses in the plastic jacket which result in a uniform, long lasting spring action.
<Anatomy of a Springcord> (http://wedophones.com/TheBellSystem/pdf/springcord.pdf)
Thanks Keith. A nice document. I guess we were on the right track with our baking method(s).
I tried this tonight for the first time tonight, and I got some interesting results, good and bad. First though, a good tip. I bought the dowel and cut it to fit precisely within the width of the oven. That allowed the dowel to rest on the ridges on the sides of the oven. That way there's no worries about how to suspend it. Obviously, if you have a really long handset or coiled mounting cord, this method might not work, because you'd need a dowel longer than the oven's width. But for standard handset cords, it's perfect.
(http://i43.photobucket.com/albums/e376/bingsterdc/PA240009.jpg)
I set the oven to approximately 265 after reading the article about the Western Electric cords being baked at 268. Either I had an odd cord or the temp on my oven is off, because even though the cord reset itself in a nice tight coil, the conductor jackets did get a bit melty. They're still covered, but they got stuck together and got a few bubbles. I'm glad I experimented on this particular cord first, because it was a junk cord anyway (pink that had both faded AND browned). So even though the process resulted in a nice coil, I still need a new one because of the discoloration.
Presumably when WECo baked them originally they hadn't yet been stripped down to the individual insulated conductors at each end of the cord?
If they did that after the baking process that might make the difference. Some types of insulation just might not be able to take the direct heat from the stove element when it is on.
(just thinking out loud here)
Terry
It may be a good idea to get a good oven thermometer to test your oven. I have found that my oven tends to be a little "cool" after testing it with thermometer. That MAY make a difference
I strongly agree with Dennis. Even with today's so-called "digital" appliances, the inexpensive sensors they use can be inaccurate due to simple manufacturing variances. When you set your oven thermostat to 265, the actual temperature could well have been 270 or even 280.
That's totally possible. It's an older oven, and there's no gradation between "250" and ""275" on the knob, so I just set it between those two marks. Next time I try this, I'll definitely go with a much lower temperature.
I have had plenty of success with setting cords on top of the portable electric oil-filled heater or putting them into the over at below 200F. I do not think that the temperature needs to be very high at all.
Larry
I have an electric heat gun used for heat shrinkable tubing. No idea how hot it works out to be, but I've had good results heating up a cord with that, only takes a minute or two, just have to make sure to keep the gun moving and heat it evenly.
I just did another at 200 degrees and it worked perfectly with no damage to the conductors. The coil of the cord was fine, but it was very stiff. The cord came out much more flexible, but I did have to reverse the coil again to get it to retract completely. I'm very happy with it.
I agree with Darrin, I would keep the Temperature under 220. I put mine on the window of my car in summer and it works fine.
Also in another topic we cover the recoloring of pink handset cords.
D/P
Did a cord for an AE80 a couple of weeks ago, in the oven at 240F for 2 hours wrapped around a narrow bamboo cane as I had run out of dowel, then outside in about -13F (-25C)!!
Cord came up brilliantly - springy tight coils, and a great shine to it too.
Word to the wise though - don't secure your cord at either end with metal bulldog clips! They're very strong with sharp edges, and when the plastic softens, they cut through! Didn't completely trash the cord thankfully, but exposed the inner conductor coatings. Thankfully at the ends of the cord that are inside the handset and phone.
This is an old thread, but I thought I would add my results to the stew.
1. Handset cord from a 354 dated 5-55. Cord was grubby, coils kind of loose, a couple twists.
2. Ran it through the dishwasher, which cleaned it up nicely.
3. 5/16 inch dowel - it's what I had.
4. Cord secured to the dowel with cable ties at the strain reliefs. No duct tape.
5. Set the dowel into the sides of the oven as pictured by Bingster on 10-24-10.
6. Electric oven set to 250 on the knob (no thermometer available).
7. In an electric oven, the heating element puts out a lot of direct radiant heat, which could heat the cord well beyond the thermostat setting. (Just want to heat the cord evenly, not barbeque it.) So I did three things:
a) Preheat the oven before putting the cord in.
b) Put a cookie sheet on the lowest rack to shield the cord from the element's radiant heat.
c) Turn on the Convection function - the circulation should ideally eliminate hot spots.
8. Bake time 2 hours.
9. Into the freezer immediately.
10. Freeze time 3 hours.
11. Warm to room temp time 1 hour before unwrapping.
Results: Looks like a new cord! No need for photos beyond what have already been posted, I think. I did not go back and rewrap in the reverse direction.
Question: the WE article called "Anatomy of a Spring Cord", linked by KeithB, describes only 8 minutes of baking, and makes no mention of freezing at all. In this thread, most of us are descrbing at least two hours of baking and more hours of freezing. Why? Has anyone tried the shorter cycle?
It's always good to hear the results that others get, Bill. Personally, I dispense with the freeze cycle altogether, and using just the baking, get great results.
Bill, on some of my attempts I used to do the longer baking times, higher temps and the freezer method. (Actually set it on the back porch in the dead of winter...colder than freezing).
I switched to the method in the article Keith B posted and got favorable results. I don't recall the temperature now but I think it was 150 degrees (I'd have to refer to the article). The baking time was much shorter and then just a short time in the refrigerator. Afterward I let it warm to room temperature before removing from the dowel.
Results may vary as they say. Sounds like your results were good.
This looks like the right thread to place this PLEA for Help!
Everyone has done wonders with their repairs on those stretched out coiled cords, but what about Cloth Covered Handset Cords?
I have a Rose 302 with a slightly (??) distorted handset cord. Anybody know how to make it look new again?
I saw a thread back in March of 2010 where ETS1979 showed the before and after pictures of a Red 302 he worked on. Everybody drooled over his beautiful work but nobody asked if he restored the handset cord or if he replaced it (at least not that I could find).
My cord is in fine condition (no breaks or frays), I just want to tighten it up to match my others.
Any Ideas?
I wouldn't want to put a cloth cord into an oven, but I would try wrapping it around a dowel, putting it into moderately hot water for several minutes, and then setting in a cool dry area, like a refrigerator, to dry.
Larry
Larry,
Actually not a bad idea. I'll run down to Lowes today and get me a dowel.
I'll keep you posted.
Here are the results of my cloth cord experiment.
I originally wrapped it around a 3/8th inch Poplar dowel rod for 2 days to see if just doing this would have an effect. It did not (Rose Phone Cord 1).
I took it off the dowel rod and washed the cord with regular hand soap in warm water (my wife thought it might fade in too hot of water).
I rinsed thoroughly in cold water.
I wrapped it tightly around my 3/8th inch Poplar dowel rod and secured it at both ends with twist ties (Rose Phone Cord 2).
I allowed it to sit in the refrigerator for 24 hours.
The results were satisfactory.
As you can see in the picture, after I took it off the dowel rod, it was much improved (Rose Phone Cord 3), but I'm pretty sure if this were to be used more that a dozen times it would stretch back out pretty easy. There was no stiffness to it like a new(er) cord would have had.
My wife and I talked about starch, but decided against it.
Here it is mounted back on the phone (Rose Phone Cord 4). and ready to put in the display case.
I know that "Old Phone Works" uses a company in California to coil their cords. I think I will try to get the name of them and ask what procedure they go through and see if I can apply it. But for now I'm pleased.
Larry, Thanks for the refrigerator idea. I thought about putting it in a black bag and placing it in the car in the heat, but I went with your idea because it seemed less punishing on the cord.
I found that washing cloth covered wires with Woolite gives excellent results.
The cord looks much improved. A trick for tightening the loops is to reverse them. It's a bit tedious, but it can produce good results.
Larry
Woolite and reverse wrapping. I never thought of Woolite. I want to see if I can find that California Company "Old Phone Works" uses to see what tricks they suggest (if any), but I will likely be coming back to that reverse wrapping idea. Thanks for the ideas and comments.
I'm not sure they would tell you. I asked how they polished their bakelite and never got a response
I've used Woolite on several cloth cords, both Brown and Ivory. It really helps remove the dirt. I just soak the cords in a bowl containing Woolite and then gently scrub them with a tooth brush. Let them air dry.
I have not tried to improve the stretched coils of a cloth cord but have one that needs it. I'm anxious to see your results.
Quote from: Dennis Markham on July 25, 2011, 10:38:16 AM
I've used Woolite on several cloth cords, both Brown and Ivory. It really helps remove the dirt. I just soak the cords in a bowl containing Woolite and then gently scrub them with a tooth brush. Let them air dry.
I have not tried to improve the stretched coils of a cloth cord but have one that needs it. I'm anxious to see your results.
Dennis.....did you notice if your teeth were whiter after using the Woolite on your toothbrush? ;D.....Doug
Doug:
Oh, that's why! ;) ;)
Quote from: Doug Rose on July 25, 2011, 10:52:13 AM
Dennis.....did you notice if your teeth were whiter after using the Woolite on your toothbrush? ;D.....Doug
Doug, I don't know about my teeth being whiter, but my moustache hairs are softer.
Recoiling the lazy way:
I just had to try this, so I took a cord, coiled it around an 8 mm bolt (from the hi-hat to the drum set) clamped it and ran it trough the dishwasher at 70 deg C. When it was dry, and cooled down it looks great, and it was clean too :D
dsk
Quote from: Dan/Panther on October 17, 2008, 12:20:15 AM
If you have a distorted, or bent coiled handset cord, that is still in servicable condition, but frankly looks too bad to use. Try what I did.
Take a piece of wooden dowel, or steel rod, 3/8 of an inch in diameter. Find or cut a piece that is about an inch or two longer than the cord is when completely compressed together.
Secure one end of the cord to the dowel or rod, using duct tape. Then coil the cord tightly around the dowel, or rod. Secure the other end with duct tape.
Then secure the ends with tiewraps.
Now run hot water over the coiled cord, dry off with compressed air, or blow the water off, then let set until completely cooled. The coil will now be like new.
If the cord was dirty, you can also clean it before you wrap it around the dowel or rod.
Dan
Dan, I tried this method for the first time since it seemed to be a "quick and dirty" method that was easy to do with stuff I had on hand. I coiled the cord on a 3/8" wooden dowel and secured it per your instructions, poured boiling water over it, let is sit in the hot water for a spell (not real long) then ran it under cold water and dryed it off with a hair dryer. It worked fairly well. Only question now is will the cord stay that way? This was the latest phone I acquired, a 52 black 500. The cord was actually worse than in the before picture because I've been using it as my main work phone.
Quote from: Dan/Panther on October 19, 2008, 06:15:53 PM
Here are the results, of the cord two days on the rod, in the sun, one day in the freezer.
The sun did work better than hot water. If the cord had been in the hot water longer it may have worked as well, but the sun method seems safer.
D/P
that cord really came out nicely, I will remember that trick.nice work dan/panther.
Quote from: Brinybay on September 21, 2012, 08:01:57 PM
Dan, I tried this method for the first time since it seemed to be a "quick and dirty" method that was easy to do with stuff I had on hand. I coiled the cord on a 3/8" wooden dowel and secured it per your instructions, poured boiling water over it, let is sit in the hot water for a spell (not real long) then ran it under cold water and dryed it off with a hair dryer. It worked fairly well. Only question now is will the cord stay that way? This was the latest phone I acquired, a 52 black 500. The cord was actually worse than in the before picture because I've been using it as my main work phone.
Here's a slight variation that work well for me today without using water.
Have a 1970'ish black Trimline that came with a distended coiled cord. Not real bad but had been stretched out in the past.
Wrapped it around a wood dowel the exact diameter of the inside diameter. Taped one end down with Painters tape and tightened the coils on the cord to the other end which was also taped down. To protect the old style connectors, I took a piece of soft foam and cut a slot in the center down the access so the foam could be slipped over the connector, both ends. Taped the foam to the dowel to keep it stationary and give the foam a bit of protection.
Placed the part of the dowel with the cord inside of a
3" diameter 4" ID by 24" long cardboard tube (1/8" wall) making sure the cord was centered length wise and also propped up or centered in the middle of the tube so the cord did not touch the cardboard tube. I blocked off about 75% of one end and stuck a hair dryer in the other making sure the air blew down the inner side of the tube allowing it to hit the blockage at the other end and some of the hot air return on the other side of the tube.
Put the 1875 watt hair dryer on low and checked the temperatures of the air on both ends and the exterior of the tube on both ends every few minutes until the temperature stabilized. I use a digital infra-red thermometer. I kept the hair dryer on for 30 minutes. The hair dryer end stabilized at 180 F and the far end, 175 F. The exterior of the tube hit 135 F on the dryer side and 125 F on the far end.
After 30 minutes, I took the dowel out and placed it in the coolest corner of my basement dungeon where it sat for several hours. Removed the tape and the cord from the dial and was impressed at the improvement in the coiled cord. If I have a before picture on my other computer, I'll add it later. For now, the first image below shows the set up and the second, the results.
Before using it, I did heat the yellow on high heat and it did not melt and stayed cool in the center - the effect of trapped air in a material like fire brick or shuttle tiles. The tape kept the foam from being hit by hot air directly.
Next time I do this, I'm going to make a smaller inner diameter tube filled with holes so the hot air is evenly distributed inside the larger tube, getting the temperatures at both ends the same. I may also let it go to 45 minutes to insure thorough heating of the cord.
If this can be duplicated, it, in my opinion, would be much more simple that borrowing the kitchen oven or dealing with the mess of hot water. I'm not sure what the effect of cooling quickly has on this rejuvenation.
John,
Now that's very clever!
Another entree into my list of tricks!
Thanks for posting!
Benny
The Western Electric manufacturing procedure was to wind the cord onto a steel rod and heat it for 8 minutes at a temperature of 268 ºF to make the coil spring permanent. After cooling, the coil was rewound in the opposite direction which provides uniformly tight spring coil.
Using flowing heated air is probably a good arrangement as that avoids hot spots by averaging exposure. In your tube gadget you could probably easily mount a thermocouple to control the power delivered to the heat gun.
How about using a piece of PVC instead of cardboard, making it a "permanent dedicated" tool?
I have a slightly different method for restoring cords. I wash them in warm soapy water which relaxes the corl somewhat. To get the tight curl back I reverse the twist one coil at a time. Have a look at the video link below to see how I do it.
https://www.youtube.com/watch?v=Mo3d3WgnoZc (https://www.youtube.com/watch?v=Mo3d3WgnoZc)
Quote from: Pourme on January 22, 2017, 11:42:53 AM
How about using a piece of PVC instead of cardboard, making it a "permanent dedicated" tool?
Well, I had the 4" ID heavy duty mailing tube and PVC in large diameter is expensive and heavy. I think the cardboard is a better heat insulator and would also stay cooler on the exterior with room air keeping it cool. It is also lighter in weight but may dry out over time. PVC might heat up more and stay hot longer after use.
I'm thinking of making a permanent tube by putting 1 1/2" or 2" PVC perforated tube down the center of the cardboard tube (they sell perforated drain tubing but it's 4" in diameter - way too large) so will have to drill it myself. In doing so I would not drill 6" on one side of the middle of the smaller tube and I would put a 2" "T" fitting on the center of the cardboard tube for the hair dryer. I'd leave the ends of the smaller tube open but seal off the cardboard tube thereby forcing the hot air to travel through the perforated pipe in a more uniform way before exiting. The undrilled area in the center would be in front of the "T" which would prevent air from the hair dryer directly hitting the cord in the middle.
The important two things is mounting the dowel in the center of the tube so it does not contact the PVC and making sure there is good air flow with no back pressure which would over heat the hair dryer and cause its internal breaker to open. Spacing of and increasing size of the holes moving away from the center could provide a fairly laminate flow of heat over the cord, similar to the WE hot rod method (the reason why the inside of a coil is is flat), and as long as the holes could handle the hair dryer's CFM output, all should work well.
This is 4" drain pipe.
Home Depot sells 2' long 4" diameter (pre-cut) sections of PVC pipe for about $7 - not bad. Yes, they could be used as the outer pipe in stead of a cardboard tube. If doing so, it might work well to wrap the exterior of the 4" pipe some sort of insulating material, (corrugated paper, for example) to keep the tube cool to the touch. The 4" tube is much heavier than cardboard and will retain heat a lot longer, but would work fine with taking precautions.
I also found that a 4" PCV coupler just fits over a 4" mailing tube so I can use that to put around the middle of the cardboard tube and be a firm support for the 2" PVC "T" that will hold the heat gun in place.
I have my drilling guide done so next step is to drill the 2" PVC pipe, assemble all parts and check the heating distribution over the length of the 2" pipe. If uneven more hold can be drilled and other sealed up to get the temperature over the whole 2' pretty much even.
More to come.
Finished construction on the hot air chamber and tried it using a somewhat bent and stretched modular handset cord (yes, no before pictures).
The first picture below is a 44" long, 4" diameter PVC pipe drilled to convey air into and around the inner cord chamber evenly. Half of the very center area was not drilled so the heat gun would not directly enter the inner tube. I used 1/2" holes, then 3/8", then 5/16" and finally 1/4" holes moving away from center.
To come up with a drill hole pattern, I first had to figure out how much air the heat gun was creating. I used a 50 gallon garbage bag to capture the hot air and timed it from start to completely full. Did that a few times to get an average fill. Converted that to cubic feet per second and used that to determine how many square inches in holes to pass the air without backing up and causing the heat gun to overload, to flip its circuit breaker open. The resulting drill pattern is what you see in the first image. Larger holes near the center moving to smaller holes at the end causing most of the air to enter near the middle but letting hot air enter directly at the ends to even out the temperature.
The top of the second image is the completed tube. The 2" diameter drilled tube was placed inside a 2' long 4" diameter heavy cardboard tube using rings on each end to center and hold the tube in the center and to force all hot air through the holes. The center is a 4" PVC connector drilled to accept a 2" PVC T. A 2" diameter hole was drilled in the tube allowing air to enter the cardboard tube where no holes were drilled in the inner tube. The bottom is the end view.
After inserting the cord wrapped on a wood dowel, with the modular connectors covered with soft foam, the dowel was centered using 22 gauge wire run through 1/8" holes in each end, enough to allow centering of the dowel.
Put the hair dryer in the "T" and turned it on low, same setting as my above experiment. It took about 5 minutes for the air coming out of the end to stabilize at about 145 F. At that point, the cardboard tube stabilized at 120 F near the "T" and 110 F at the ends. After 25 minutes from stop, I realized using the low setting with this air tube resulted in a lower temperature than forcing the air into an end - probably better air flow. At that time, I turned the heat gun on high and in about 5 minutes, the temperature reached 185 F. At that time, I put a rag over each end, turned off the heat gun and securely covered the ends to keep the hot air in the tube.
Let it cool naturally for about a hour. The cord, when removed from the dowel, looked like NOS. The bottom image shows the cord on the phone and as it looked after taking it off of the dowel.
Next time I'll take before pictures, now that I know this will work as planned. Total cost, less than $10.
Pretty impressive John! Are you going to be the "coil cord restoration guy" like Steve Hilsz is the dial guy?
Are you using a hair dryer or the commercial type heat gun?
Terry
Quote from: AE_Collector on February 08, 2017, 04:13:29 PM
Pretty impressive John! Are you going to be the "coil cord restoration guy" like Steve Hilsz is the dial guy?
Are you using a hair dryer or the commercial type heat gun?
First, thanks. Much more controlled than using a kitchen oven. Then, . . .
1) No.
2) Using a 1875 watt hairdryer that was extra so ended up in the dungeon. On the low setting, it should last for some time at a half hour per cord. Will get a commercial type when this one gives out.
One thing that this method has going for it is that the cord was once coiled so it's not like turning a straight, round cord into a coil. The coiled cords still have a good percentage of coil in them so this is more of a touch up, a get it back to near original fix.
Have to do a few more cords before I become convinced that this is better, or easier, than sticking it in an oven - which also works.
Had anyone else tried just twisting it backwards rather than going to the teouble of heating it up, because this definitely works well on UK cords.
Andy
Quote from: andy1702 on February 08, 2017, 05:29:13 PM
Had anyone else tried just twisting it backwards rather than going to the teouble of heating it up, because this definitely works well on UK cords.
I did twist it backward first, before heating, and all I got was the same issues in reverse - gaps, bends, big coils.
That all went away after heating on a dowel. Next cords I do (I'll take before and after), I will twist one before heating and the other not to see what difference that makes.
The heat method has been proven to work for cloth and non-cloth cords. Some reverse twist after heating. Reverse twisting won't fix an elongated coil or group of coils. Reverse twisting can help with spacing of the coil but does nothing for bends and stretches. At least, in my experience of working with cords.
Just adding a way to heat should anyone care or want to do the same. It's a lot easier to stick a wrapped dowel inside a tube and turn on a hair dryer for a half hour than deal with a hot oven.
That's very interesting because stretched cords on UK phones (plastic cords) always seem to go back into a tight coil just by reversing them.
Here too but I think the problem is when a cord has a reversal of the coils somewhere in the middle that has been that way for a long time. Up to the point of the reversal may have tight coils and then loose coils from there on. There is no way to remove the reversal in the cord as one side will always be loose and the other tight.
A cord that is simply stretched out without any reversals in the coils can be wound backwards to tighten it up though it always seems to me that it then comes out of the handset facing the wrong direction initially which makes it likely that the coils will reverse there with use.
Terry
Had a coiled cord from a 1500 which had tight, uniform loops but 2 in a row were bent at a 45 degree angle. Didn't take a before photo but after heating it up to 150 over 15 minutes and then turning the gun on high to get the temperature up to 190, I covered each end with a rag, turned off the gun and let it cool naturally for about an hour. Kink is gone, cord looks like NOS. The coiled cord "oven" works well. Will take before photos next time.
Yet another great set of posts Teleplay!
Quote from: TelePlay on February 08, 2017, 06:15:45 AM
The first picture below is a 44" long, 4" diameter PVC pipe drilled to convey air into and around the inner cord chamber evenly.
I had a hard time visualizing your description until I thought that your reference to the 4" PVC pipe should have said 2" as is mentioned later in the paragraph. Is that correct or am still confused?
Thanks!
Tina Loyd
Quote from: cloyd on September 04, 2017, 10:10:35 AM
Yet another great set of posts Teleplay!
I had a hard time visualizing your description until I thought that your reference to the 4" PVC pipe should have said 2" as is mentioned later in the paragraph. Is that correct or am still confused?
Thanks!
Tina Loyd
It's made from 2 different pipes. The 4" heavy cardboard tube is the "outside" of the "oven" with only one large hole in the center to allow the hot air to be blown in.
The 2" PVC pipe had many holes drilled into it to allow the hot air entering the the 4" tube to pass through or enter the 2" pipe evenly so one part of the cord does not get hotter than the other parts.
The handset cord is wrapped tightly around a dowel and place inside the 2" pipe as close to center as possible. I use station wire and holes drilled into the end of the 2" tube to do this.
Over all, this setup allows hot air to evenly enter the 2" pipe and exit out the ends.
Picture from the end shows all except the center dowel that would hold the handset cord.
Thanks, that helps!
Did you drill holes through each end of your dowel for the wire to suspend it and the cord? I'm guessing you don't want the cord to rest on the 2" PVC tube when it is getting so hot.
I'm going to put this on my list of things to make!
Well done!
Tina Loyd
Quote from: cloyd on September 04, 2017, 04:56:05 PM
Did you drill holes through each end of your dowel for the wire to suspend it and the cord? I'm guessing you don't want the cord to rest on the 2" PVC tube when it is getting so hot.
No, I run the station wire through the holes in the end of the 2" pipe and around the dowel. Do that from 3 different angles and I have a way then to adjust the dowel, to get it centered. That's a temporary thing. Now that I know the oven works, to both hold and center the dowel I had planned on drilling and tapping 3 holes, 120° apart in the 2" PVC and then using thumb screws, like in a Christmas tree stand, to center and hold the rod. I'd epoxy glue a nut and washer on the end of each thumbscrew to provide a larger surface to engage the dowel. Plans in the works, no time to do that yet. Next time I need to tighten a cord, I will get to that.
I have since purchased some smooth, round aluminum rod 4' long by 3/8" diameter. Wood is an insulator. Aluminum will allow the handset cord to heat all the way through. Haven't had time to try that yet.
It's been some time since I found 3/8" round aluminum rod in a 3' length but I finally got a change to use it today.
Did everything the same as I did with wood dowel and it turned out well. Once again I forgot to take a before photo but I do have the first image from the eBay listing. The handset cord really is matching beige, just dirty grey. You can see it was not in the worst shape but it was stretched out in the usual places.
After cleaning, wrapping on the aluminum rod, heating, cooling and unwrapping the cord, it turned out nice.
One thing I did notice was the cord stuck to the aluminum meaning the whole cord was heated. One thing I learned is before doing this, reverse twist the cord so it is back in the original position it was when made and then reverse twisted by WE. I get a better coil when doing it that way, reproducing the way it was done by we when they made these from round cords.
By the way, the phone had 4 sticker areas, glue only, and the one in the box was removed with a wood chisel - left gouges in the plastic which took a half hour to sand out.
It's a bit dis-colored, some of which came out in bleach, but leaving it as it for I know where it is going and how thrilled the guy will be to get it for free. A favor for a favor, not a collector's level phone.
Quote from: cloyd on September 04, 2017, 04:56:05 PM
Thanks, that helps!
Did you drill holes through each end of your dowel for the wire to suspend it and the cord? I'm guessing you don't want the cord to rest on the 2" PVC tube when it is getting so hot.
I'm going to put this on my list of things to make!
Well done!
Tina Loyd
Regular Member Post (http://www.classicrotaryphones.com/forum/index.php?topic=20151.msg206412#msg206412)
To complete this project for those who are interested in physical phone restoration work, I installed my idea of how to hold the cord carrying rod in the center of the inner tube.
After drilling 3 holes 120° apart in each end of the inner PVC tube, I tapped the holes and screwed 1/4" NC 20 machine bolts into the inner PVC tube. They meet in the middle and hold the rod, a 3/8" aluminum round, in the center keeping the coiled cord on the rod from touching any part of the inner tube during heating and allowing an even hot air flow around the coiled cord. The bolts are easily turned into and out of the PCV threaded pipe by hand and quickly place the rod in a centered position.
The aluminum rod replaced the wood dowel originally used because wood is an insulator and keeps the inside of the coil cooler and not heat treated as much as the outside of the coil. The aluminum rod attains the same temperature as the cord and as such, heats the inside of the coil to the same temperature as the outside of the coiled cord. This provides a much better reforming of the coil than when a wood dowel was used.
This set up has always worked well for me to turn a cleaned, stretched out handset cord into a tight, like new coiled cord.
(http://www.classicrotaryphones.com/forum/index.php?action=dlattach;topic=20168.0;attach=183499;image)
The last 3 or 4 coil cords I've had to clean and put a permanent in, I have used a plastic coat hanger with the section cut out at the base of the hook to the end of the horizontal section. I can thread the coil onto it, twist tie one end below the hook and snug it up and twist tie the other end at the cut end of the horizontal. I give the cord a good saturating spray of scrubbing bubbles bathroom cleaner and rinse with hot water. I give a wipe off, then run the hair dryer over it and let it set awhile to finish drying. It just hangs up like a normal hanger.
Quote from: TelePlay on April 22, 2018, 08:51:13 AM
The aluminum rod replaced the wood dowel originally used because wood is an insulator and keeps the inside of the coil cooler and not heat treated as much as the outside of the coil. The aluminum rod attains the same temperature as the cord and as such, heats the inside of the coil to the same temperature as the outside of the coiled cord. This provides a much better reforming of the coil than when a wood dowel was used. This set up has always worked well for me to turn a cleaned, stretched out handset cord into a tight, like new coiled cord.
Regular Member Post (http://www.classicrotaryphones.com/forum/index.php?topic=20151.msg206412#msg206412)
My tube furnace continues to turn out fantastic results, even better since I started to use an aluminum rod.
I usually forget to take before images but did so this morning. The cord wasn't "that" bad but it needed recoiling.
After 45 minutes in the furnace with the hair dryer on high (and letting it cool naturally over time - about and hour), the cord coil was restored. The aluminum rod lets the inside of the coil in contact with the aluminum rod and attain the same temperature as the outside of the coil when on the rod, something wood could not do since wood is an insulator. The cord is fully heated with the metal rod.
(Note: the color difference is due to the background used; the before was taken on a grey cloth and the after on a white board - shows the iPhone camera has a problem, or is given a problem, by using certain colored backgrounds, the dark red is more accurate).
Amazing results. Like new. :)
Here is another restored cord. After cleaning the cord and getting the coils all going in the same direction, the cord showed a bend near the middle which did not look good when handing from the handset. 45 minutes in the furnace and it's near NOS.
Nice! They do come out looking like new! Great job! Thanks for sharing with us. I seem to be working on all cloth cords right now so I have not needed this yet but I am excited to try it out. Have you had one done long enough to tell if it is a permanent repair or not?
Quote from: HarrySmith on July 12, 2018, 12:28:16 PM
Have you had one done long enough to tell if it is a permanent repair or not?
The beige 554 (above) was done 3 months ago and is still in the same condition.
(http://www.classicrotaryphones.com/forum/index.php?action=dlattach;topic=20168.0;attach=183499;image)
With normal use, they don't return to the "before" state. Any coiled cord can be wrecked by overstretching, I suppose.
I clean the cord with a mixture of 10% Acetone, 10% MEK and 80% Denatured Alcohol (really take off any hard fast grim better than soapy water, soapy water left crud this mixture then removed quickly so I start with the mixture) and after I put the cord on the aluminum rod, I go over the outside of the rod mounted cord with that same mixture. It tends to make the rubber cord a bit soft and going over the coils with a wet cloth of the mixture, some of it gets between the coils and along the rod. This, of course, evaporates off but seems to leave a better coil restoration. Can't prove anything since I would need two identical cords and treat one with the mixture to see the difference.
After 45 minutes with the drying on high, the aluminum rod on the ends outside of the furnace are too hot to touch so the inner coil has to be equally affected by the heat. Just my observations from doing them.
The next time I post a before and after cord will be of a badly distorted cord. Did one once successfully but, as typical many times, no pictures.
That beige 554 looks like it has just been taken out of the box. :)
If anyone is still trying to restore distorted coiled cords, heat is still the answer. A 3/8" aluminum rod is used to distribute the heat applied to the inner side of the coil. The metal acts as a heat sink and becoming hot itself, slows the cooling process to insure annealing of the heat treatment.
Using a new dry heat source that takes about 3 minutes to heat the cord evenly to a temperature above 190° F but not over 200° F (anything over 200° F runs the risk of melting the cord). I use a digital hand held infrared thermometer to check the cord temperature during heating.
The process steps are to first wash and dry the cord, coil the cord tightly on the rod, heat the cord to the above stated temperature range and allow it to cool slowly, for at least 30 minutes (I actually let it sit for hours before taking it off the aluminum rod).
Can do a cord from washing to treating in less than 15 minutes - washing takes the longest time.
If doing it in an oven the way the article describes (268°F for 8 minutes), to get around the problem of the inaccuracy and hot spots of typical home ovens, you can put something heavy and dark-colored (so as to get an accurate reading off it with an infrared temperature gun), such as a large, well-seasoned cast iron skillet, in the oven and preheat it to say, 400°F. Then turn the oven completely off, leave the door closed, and wait a little while. Open the door briefly to check the temperature of the cast iron skillet periodically. When it gets down to 268°F, or whatever temperature you want to use, put the cord in for 8 minutes (still leaving the oven turned off).
The cast iron skillet helps retain heat in the oven (over a period of only 8 minutes the oven will probably only drop a couple/few degrees in temperature) and serves as a good temperature reference point (temperature guns are most accurate on dark surfaces, though if you have a good oven thermometer you wouldn't need the temperature gun). Preheating the oven initially to a much higher temperature than you need ensures that by the time it cools to the temperature you want, everything in the oven is at the same temperature.
If you have something even heavier than a cast iron skillet it would work to retain heat over that 8-minute period even better. For example, I have an 18" diameter, 3/8" thick mild steel plate, seasoned, that I use as a "pizza steel." It has a lot of thermal mass (it weighs 27 pounds), which is what makes it work so well for cooking pizzas. A 12" cast iron skillet usually weighs around 8 pounds. Bricks would work good too.
Old post but useful .. I use stick of wood with the hair-dryer without problem , of course I wash the cord before :) .
Quote from: Contempra on April 28, 2023, 08:37:40 AM. . . I use stick of wood with the hair-dryer without problem . . .
Both work but have limitations.
A wood dowel is an insulator, will not heat up and conduct heat. As such, the inside of the coils, those in touch with the wood, will remain cool while heating the outside of the coils. There is no way the inside of the coils will reach the re-forming temperature with over heat (and most likely melt) the outside of the coils. A metal rod will allow raising the temperature of both the inside and outside of the cord coils uniformly. Heating only the exterior works but the unrestored curl in the interior of the cord will fight against the exterior restored coil, won't be as tight and/or the restored coil won't last as long.
Hair dryers work but are relatively low temperature compared with the commercial shrink wrap heat guns out there. One one hand it takes a long time to heat the cord with a hair dryer but the risk of damage is low. A commercial heat gun raises the temperature of the coil faster and higher but the risk of damage is high if not heating the cord uniformly and evenly.
The commercial heat gun does a better job quicker (especially if using a metal rod) but must be done thoughtfully.
I have created a heating jig to heat coiled cords on a metal rod using a commercial heat gun. Once the cord is cleaned and mounted on the metal rod, it takes about 5 minutes to reform the cord coil, plus cooling time. When done correctly, the inner coil will be slightly stuck to the metal rod indicating the interior of the coil had reached the desired reformation temperature (the cord is easily removed from the coil metal rod).
If using a metal rod, it takes at least a half hour for the coil on the rod to coil, I look at the process as being similar to annealing heated glass.
I forgot to mention that I think the coiled cords were made by tightly winding a round cord around a metal rod.
The rod with the cord in place was electrically heated to a temperature that was just below the cords melting point, a temperature at which the cord touching the metal rod deformed and when allowed to cool over time, the cord stayed coiled.
If you look at a coiled cord, the inside of the coil is totally flat (from the metal rod) and if you look between the coils, the side of coils is flat near the inside of the coil, the side of the coil closest to the metal rod.
So, to create a coiled cord they heated the cord material from the inside to a point where the round cord "melted" and took on the shape of the hot, round rod - flat. The flat coil sides shows how much of the rounded cord was flattened.
They may not have heated the outside of the round cord and, in fact, heated the rod in a cold chamber to keep the outside of the soon to be coiled cord from deforming, to keep it round.
It would be fun to put a voltage across a metal rod having a resistance, say a NiChrom rod (I'd hate to see the price of 3 foot long 3/8" diameter nichrom rod), and using a Variac to heat such a rod with a distorted coiled cord wrapped around it to a specific temperature for a period of time to reform the distortion.
Then there's passing steam through a 3/8" pipe for a specific period of time to heat and thus reform a distorted coiled cord.
Might be other ways as well.
If anyone here wins this 1955 WE Mediterranean Blue on eBay,
https://www.ebay.com/itm/326027537038
I would be willing to recoil the handset cord, if not physically damaged, for free if the new owner pays for shipping both ways.