News:

"The phone is a remarkably complex, simple device,
and very rarely ever needs repairs, once you fix them." - Dan/Panther

Main Menu

Finally working on Peking Red 302.

Started by Dan/Panther, May 30, 2014, 06:24:28 PM

Previous topic - Next topic

LarryInMichigan

I cleaned out the dirt in the crack and stretched two large rubber bands around the bottom of the shell to start coaxing the crack closed.  The plastic naturally wants to sit with the crack wide open at the moment.  I was thinking about possibly placing the shell with the rubber bands into the hot trunk of my car for an hour or two hoping that the heat would help the plastic settle in the closed position, but I don't want to warp anything.  It looks like there is just about no plastic missing from the crack area, but the edges do not perfectly meet when pressed together.

The rest of the phone is in decent condition.  It is surprisingly clean.  The middle of the handset cord is worn and covered with old tape.  The is a small gouge in the front middle of the handset, but it will probably sand out.  The front corner of one of the cradle ears is damaged a bit.  The phone probably fell and landed on it at some point.  The screw for holding the clamp over the condenser was missing, but I salvaged one from a spare 302 base.  So far, everything looks to be original with all dates from the Dec 1951 or Jan 1952.  The ringer gongs are steel.

I was somewhat apprehensive about paying well over $100 for a cracked phone, but I thought that I would take a chance.  Advice on repairing the crack will be appreciated.


Larry

WesternElectricBen

Quote from: unbeldi on May 31, 2014, 11:34:06 PM
Quote from: LarryInMichigan on May 31, 2014, 11:06:14 PM
Quote from: unbeldi on May 30, 2014, 08:32:41 PM
On the other hand, a red with a little crack sold for $140 this morning. That one could be repaired to almost perfection, I think.

Are you referring to this one: ebay link?  It arrived today and is sitting on my desk now.  The shell has a date stamp of "1 30 52" in it.  I may need some help closing the crack.

Larry
Ah...  you got it.  Great deal, I was even tempted at $190 in the earlier auction.

Yes, I have repaired a much worse crack than this on one of my reds.  Turns out the red is such an intense color, it helps making the crack almost invisible with experience. I have learned a lot from my first red repair. Since these are quite valuable, it is easy to be too cautious when working on them. I can put together a separate thread on my repair. The housing is the one I showed already in this thread; it had a long crack in the corner from the bottom edge going all the way up next to the dial.


Unbedi, could you please explain how you repaired yours or link me to a previous one? I have a thermoplastic black 302 that needs some work.

Thanks,
Ben

unbeldi

Quote from: WesternElectricBen on May 31, 2014, 11:58:00 PM

Unbedi, could you please explain how you repaired yours or link me to a previous one? I have a thermoplastic black 302 that needs some work.

Thanks,
Ben

I'll start a new thread, that's better than highjacking this one.
But... repairing black Tenite is a different story than the colors.  In fact I have had slightly different experience with almost all the colors.

unbeldi

#33
Quote from: LarryInMichigan on May 31, 2014, 11:47:26 PM
I cleaned out the dirt in the crack and stretched two large rubber bands around the bottom of the shell to start coaxing the crack closed.  The plastic naturally wants to sit with the crack wide open at the moment.  I was thinking about possibly placing the shell with the rubber bands into the hot trunk of my car for an hour or two hoping that the heat would help the plastic settle in the closed position, but I don't want to warp anything.  It looks like there is just about no plastic missing from the crack area, but the edges do not perfectly meet when pressed together.

The rest of the phone is in decent condition.  It is surprisingly clean.  The middle of the handset cord is worn and covered with old tape.  The is a small gouge in the front middle of the handset, but it will probably sand out.  The front corner of one of the cradle ears is damaged a bit.  The phone probably fell and landed on it at some point.  The screw for holding the clamp over the condenser was missing, but I salvaged one from a spare 302 base.  So far, everything looks to be original with all dates from the Dec 1951 or Jan 1952.  The ringer gongs are steel.

I was somewhat apprehensive about paying well over $100 for a cracked phone, but I thought that I would take a chance.  Advice on repairing the crack will be appreciated.


Larry

The internal stresses that have developed in the plastic can be quite enormous, causing the cracks to stand wide open. Applying heat to relieve them is dangerous as it can cause and likely will cause warping without rigid support, and I don't know that keeping it in a trunk would be enough heat.  In my case I had to use large cable ties around the entire housing to keep the crack closed.

If the edges of the crack match perfectly, which is invariably only true for fresh cracks, then perhaps super glue alone can do the job well. But I am using plastic solutions in a mixture of acetone and ethyl lactate (~2:1).  Ethyl lactate also dissolves Tenite, but it has a lower vapor pressure, so it doesn't evaporate as quickly and makes it easier to work with the solution.  The plastic solution fills empty spaces and pockets with properly colored plastic.

continued here:  http://www.classicrotaryphones.com/forum/index.php?topic=11993.0

Dan/Panther

You will need to relieve the base or the inside corners of the shell. Otherwise, your crack repair will open up as soon as you try to put the shell back on the frame.
There are two ways to relieve the problem.

One-grind down the corners of the base plate.
Two-remove material from inside the shell.

Suggestion Two This is how I prefer to do it. Your case is already cracked, so removing material from inside the corners of the case won't matter. There are raised portions of the case at each corner. I remove those with a dremel tool. I think regardless of the shell being cracked or not, this method is better in my mind than to grind down the corners of the base. Removing material from inside the shell, is completely undetectable, whereas the grinding of the base will show. JMHO.
There is a thread about the process, I couldn't find it.

D/P

The More People I meet, The More I Love, and MISS My Dog.  Dan Robinson

LarryInMichigan

I have had success with most of my 302s by hammering the sides of the base with a plastic head hammer.  The lip of the base is bent inward, and this usually allows the shell to fit over it.  I think that I am going to let this shell sit for a couple of weeks with the rubber bands before I attempt to do anything with it.  I won't have time to do anything for a while anyway.

Larry

Dan/Panther

I don't understand why everyone chooses to deform the base permanently, rather then remove a slight amount of Plastic on the inside of the shell where it won't ever be noticeable. The base bending is permanent and noticeable. The shell has a raised spot at each corner inside, just flatten that out and you are good to go. All you do is make the raised part the same level as the rest of the case. It's not thinner than the rest of the shell.
D/P

The More People I meet, The More I Love, and MISS My Dog.  Dan Robinson

unbeldi

#37
Quote from: Dan/Panther on June 01, 2014, 05:14:42 PM
I don't understand why everyone chooses to deform the base permanently, rather then remove a slight amount of Plastic on the inside of the shell where it won't ever be noticeable. The base bending is permanent and noticeable. The shell has a raised spot at each corner inside, just flatten that out and you are good to go. All you do is make the raised part the same level as the rest of the case. It's not thinner than the rest of the shell.
D/P

I do disagree with that.  Modifying the base seems to be the more robust solution. Removing plastic from the most sensitive and high-stress areas in the housing just seems like asking for further cracking. We already know that's where they crack the most, and weakening the structure in the most critical points cannot be smart, IMHO.  Essentially you're creating 'a lens', focussing the internal stresses into an area with a high probability of strain (deformation) formation.  Repairing a broken housing is already enough work, I don't want to do it again soon with even less material to work with.

Authenticity here and there, but collecting purists have to make some concessions. It seems more prudent to preserve the integrity of the housing than the base.

In addition, I have had cracked housings where removing just plastic would probably not have been enough after the repair.

I don't think the assessment is quite right about the thickness of the shell in the corner. The edge in the front or back is a little bit thinner and it appears the corner is thicker, but that thickness is extended upward equally, so it is not that the corner is thicker, but the long edges are thinner for about a quarter of an inch on the vertical dimension.

Why this is thinner, is probably connected with the ease of fitting on the base rim, which is not entirely straight, but has some slight bulges toward the housing surface.

poplar1

If the lip on the baseplate is bent--and not ground--why is this not reversible? In any case, grinding the housing is certainly not reversible.

Also, the baseplates are plentiful from cracked black 302s in case someone wanted an unmolested base.
"C'est pas une restauration, c'est une rénovation."--François Martin.

LarryInMichigan

Well, I did alot of banging around the base, and it still will not fit, so I will probably grind the corners of the base.  I do not want to risk destroying the shell by grinding it.  I did have to grind out the dial opening in my ivory 354 because the dial would not fit and the plastic was starting to crack, but I was very nervous while doing it.  I have had to grind out openings for clock bezels on a few catalin clocks.  That is a messy process.

Larry

unbeldi

#40
Even bending the base rim may not always be reversible, sure with good tools this might be accomplished and the metal could be repainted.

On some sets it is entirely sufficient to slightly bend the rim.  On others, the rim needs to be bent inward so much that as a result the very corner is forced outward, creating a sharp point. This invariably needs to be ground down to avoid pressing a sharp corner into the plastic, which would create a dangerous breakage point.

A solution to this formation of the sharp point is to cut a slot into the metal rim exactly in the corner. This makes it easier to bend the metal rim on both sides of the slot and avoids the point. But in one case, I believe, I still had to do some grinding.

The grinding can be hidden quite a bit by applying some black paint, which should also reduce the danger of rusting in the future.

unbeldi

Quote from: LarryInMichigan on June 01, 2014, 06:42:30 PM
Well, I did alot of banging around the base, and it still will not fit, so I will probably grind the corners of the base.  I do not want to risk destroying the shell by grinding it.

I did not find hammering very effective either, at least not very controllable.  I use adjustable locking pliers to grip the rim very firmly to bend it. That also puts less stress on the entire base. They can warp easily when hammered on.  The ringer usually needs to be removed for my tool, or the condenser, or both, because of the geometry of the pliers.

Quote
I did have to grind out the dial opening in my ivory 354 because the dial would not fit and the plastic was starting to crack, but I was very nervous while doing it.  I have had to grind out openings for clock bezels on a few catalin clocks.  That is a messy process.

Larry

The cases of the ivory 354 have a tendency to shrink length-wise, creating a slight oval dial recess. I also had to grind out the opening after having let the case just sit around with its dial removed for about a year (hoping I would soon get to it). I don't recall how hard it was to remove it originally.

Dan/Panther

#42
I've done several 302 cases this way, and never had any further damage. The extra plastic at the corners is exactly the cause of the cracking. If by chance I purchased a phone with the base either ground, or banged in with a hammer, I would ask for a discount or refund. JMHO. In the future if you decide to put the shell on another base, you will have to modify that one also. The slight bit of plastic removed from the case will not take as much away from it's value, as the already present Crack will.
I don't think everyone realized exactly how little amount of plastic you have to remove to make a big difference in the case fitting easily or fitting very snug.
If you look at the photo, you can hardly see where the plastic has been removed. It sure looks less invasive than a banged in corner or ground off base. Neither of which is undetectable, or reversible, where the plastic is removed, unless you are told, you would probably never notice it. You would think it was simply wear from the case being taken off and put back on. In fact if I polished the spot, you would NEVER know.

D/P

The More People I meet, The More I Love, and MISS My Dog.  Dan Robinson

Dan/Panther

Here is another photo after a slight polishing.

D/P

The More People I meet, The More I Love, and MISS My Dog.  Dan Robinson

Dan/Panther

I finished up the Peking Red, and put Her into service this morning.
D/P

The More People I meet, The More I Love, and MISS My Dog.  Dan Robinson