Author Topic: Rubber Cord Rejuvenation Attempt  (Read 1036 times)

Offline WEBellSystemChristian

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Rubber Cord Rejuvenation Attempt
« on: September 05, 2016, 07:17:25 PM »
I will be attempting to restore a stiff handset cord by soaking it in olive oil. I know that Mineral Oil restored a shrunken Ivory 302 cap for another member, and I will try it out on a rubber cord with damaged conductors. If all goes well, this could work for early coiled cords and straight cords permanently bent out of shape. Heck, it could even bring some of the shine back!

I only left the center section of the cord in oil, for comparison later.

Wish me luck!!
« Last Edit: September 05, 2016, 07:27:40 PM by WEBellSystemChristian »
Christian Petterson

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Offline Pourme

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Re: Rubber Cord Rejuvenation Attempt
« Reply #1 on: September 05, 2016, 07:45:48 PM »
What issues are you attempting to address? Flexibility, shine and richness of color, perhaps?
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Offline WEBellSystemChristian

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Re: Rubber Cord Rejuvenation Attempt
« Reply #2 on: September 05, 2016, 08:30:28 PM »
What issues are you attempting to address? Flexibility, shine and richness of color, perhaps?
Mainly flexibility, but shine would be a nice bonus... :)

Making the cord supple would be nice, too, and would make it look new again!

The only issue that could happen is the outer jacket itself becomes like-new, but the conductors inside would remain stiff, and the extra flexibility from the cord could cause the conductors to break.
Christian Petterson

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Offline Pourme

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Re: Rubber Cord Rejuvenation Attempt
« Reply #3 on: September 05, 2016, 08:46:38 PM »
Good luck....We will be watching!
Benny

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Offline WEBellSystemChristian

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Re: Rubber Cord Rejuvenation Attempt
« Reply #4 on: September 05, 2016, 09:23:45 PM »
Good luck....We will be watching!
If this works, I'm going to try a 1951 straight cord that's badly misshapen, mainly because it stiffened while sitting wrapped up in a box most of its life.
Christian Petterson

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Offline Pourme

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Re: Rubber Cord Rejuvenation Attempt
« Reply #5 on: September 23, 2016, 12:20:53 PM »
How did the experiment go, Christian?
Benny

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Offline WEBellSystemChristian

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Re: Rubber Cord Rejuvenation Attempt
« Reply #6 on: September 23, 2016, 07:31:46 PM »
Well, I let it sit for a week or so, and I don't think it changed at all. At first, I thought it looked glossier, but it was just excess oil, and it wiped off.

In a PM, Teleplay recommended that I use a lighter oil mixed in to penetrate the surface. I may try that!
Christian Petterson

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Offline Pourme

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Re: Rubber Cord Rejuvenation Attempt
« Reply #7 on: September 23, 2016, 08:00:34 PM »
I have a cord that is stiff on a AE jukebox phone...I don't know if a cord like that can be made playable though, it's not just the outer cover but the covered wires inside that have aged and dried out as well...
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Offline TelePlay

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Re: Rubber Cord Rejuvenation Attempt
« Reply #8 on: September 23, 2016, 09:35:21 PM »
This is what I found on an antique radio site.

"Got me interested in this again. A quick Google search for softening rubber got lot of hits and the most common method seemed to be mixing one part wintergreen oil with thee parts 91% isopropyl alcohol. After soaking the alcohol evaporates leaving the thin oil in the rubber. Wintergreen oil is used for body massage so it is light and non toxic."

Wintergreen oil (methyl salicylate) is a bit pricey

http://www.ebay.com/itm/111823289099

 so not in my experimentation budget right now.  Also, in its concentrated form, it is an irritant. When diluted, not so. It is also soluble in the alcohol so you don't get the oil and water separation problem.
            John . . .

              

Offline Pourme

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Re: Rubber Cord Rejuvenation Attempt
« Reply #9 on: September 23, 2016, 09:56:15 PM »
That is pricy...wow

What dangerous wild animal do they have to wrestle to the ground to extract that?
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Offline TelePlay

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Re: Rubber Cord Rejuvenation Attempt
« Reply #10 on: September 23, 2016, 10:15:38 PM »
That would be wild plant, the one with the round, red berries.

I think it's made synthetically these days. A little goes a long way in most applications, but not this one.
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Offline TelePlay

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Re: Rubber Cord Rejuvenation Attempt
« Reply #11 on: January 18, 2017, 04:32:16 PM »
There are two other, probably more, topics about softening stiff cords (not cloth). I have them and had an idea early this morning. Did a test on two short segments of the cord and since it showed promising results, I did a long section today. I had tried other methods but they did not work. This treatment seems to work.

Straightening straight rubber cords

Softening hard Neoprene cords

Test #1): Soak a section in hot mineral oil for 5 minutes - after cooling, the cord was more flexible

Test #2): Soaked a section in hot mineral oil for 10 minutes and after wiping off the mineral oil, while still hot, covered the section with a thin coating of Skin-So-Soft. After it cooled, very good results - straight and flexible.

Test #3): Soaked a long section in 2 cups of hot mineral oil containing 2 Tablespoons of Skin-So-Soft for 20 minutes, wiped off the mineral oil and covered the section with a thin coating of SSS while it cooled. A paper clamp was attached to the bottom restraint and a household scissors stuck through it to keep it straight while cooling, a few ounces at most. After cooling, very close to new with respect to flexibility.

The oil mixture can be saved and reused. I suspect 4 to 6 cups of mineral oil with one Tablespoon of SSS per cup would be needed to submerge a whole cord, except for the ends.

The mineral oil I used was the farm non-edible stuff available from farm supply stores in their animal health section.

I heated the oil in a steel pan sitting inside another steel pan with water. A larger in diameter pan would be best to treat a very stiff cord in that it should be treated before bending to prevent cracking in the inner sides of the bend. In other words, the pan/oil should be big and deep enough to cover the cord as is (cord should not be bent to fit into the oil pan).

Once brought to a full boil, the heat was turned down to a simmer. The water at the surface stayed about 205 degrees. The oil stayed at about 195-200 degrees.

I'm not sure if more or less SSS would work better or worse or if something else, such as Wintergreen Oil, would work better. Mineral oil is safe to use. Other oils may be better but from what I have read, mineral oil seemed like a good thing to try and it is the main ingredient of SSS. I chose 20 minutes, 30 may be better or worse.

The blue and green circles show the hanging points between photos, should have hung them from the same point but didn't.

The purple box is after the first test (no before photo). The purple circles are before and after of Test #2.

The red arrows show the two places where the cord was broken. I used electrical tape to secure these breaks while treating. Test #3 above covered the length of cord between the red arrows.

While to treated cord is now flexible, the one major problem is that if the stiff cord was in any way tried to be bent straight, small cracks in the cover appear and 1/8" apart on the inner side of the rounded bend. After treatment, the cracks were there but the cover was not so brittle as to crack fully and fall off.

If someone else would like to try this to see if it can be replicated, please post your results, good or bad, here.
            John . . .