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Restoring a WECo pink 500 Set - Sanding and Solvent

Started by cihensley@aol.com, July 01, 2011, 02:45:30 PM

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cihensley@aol.com

Fixing the crack. Strip of plastic blister packaging super glued to shell for crack reinforcement. One of the ribs removed to make the liquid plastic patching material. The crack grooved with a Dremel tool.

Chuck

LarryInMichigan

What are you using to dissolve the plastic to fill the crack?  My AE80 shell is ready for the procedure.

Larry

cihensley@aol.com

Larry:

A few drops of acetone. I have the small pieces of plastic and the acetone in a small bottle with cap. I let it sit overnight to dissolve fully. It should be the consistency of heavy syrup when it is ready. I am assuming the AE is Tenite or ABS like the WECos. Jorge or someone else may know for sure.

Chuck

LarryInMichigan

Chuck,

Do you use pure acetone, or will nail polish remover work?  The AE80 shell I have to fix is tenite.  The later ones were ABS, I believe.

Larry

cihensley@aol.com

Larry

I use pure acetone. I get it at the hardware sore. I don't know what is in nail polish remover.

Chuck

AE_Collector

Quote from: LarryInMichigan on July 06, 2011, 08:32:00 PM
The AE80 shell I have to fix is tenite.  The later ones were ABS, I believe.

Larry

There are early soft plastic and later hard plastic AE shells. I have always assumed that they were pretty much the same plastic as WECo shells but am not positive about that.

Terry

LarryInMichigan

The AE80 shell definitely appears the be the same sort of tenite as the WEs that I have.  The phone was made by Leich, and it has "3-59", which i assume is the manufacture date, stamped on the bottom.  The finger wheel is the early type with the chrome card retainer ring.

Larry

cihensley@aol.com

Initial crack repair and repair sanding. A couple of low spots and air pockets to touch-up yet.

Chuck

old_phone_man

Very Nice Work!  I'm impressed.  So will you do the same thing to fill the air pockets and low spot?  Do you anticipate needing to Dremel again?

cihensley@aol.com

old_phone_man:

Thank you. I doubt if I will use the Dremel again. I may try to liquify the plastic with methylene chloride rather than acetone to see if it dries without the air bubbles.

Chuck

TelePlay

Quote from: cihensley@aol.com on July 07, 2011, 09:00:32 PM
old_phone_man:

Thank you. I doubt if I will use the Dremel again. I may try to liquify the plastic with methylene chloride rather than acetone to see if it dries without the air bubbles.

Chuck

DCM may be the better solvent so I look forward to hear how that works for you. It's not as safe as Acetone but being a more polar chlorinated hydrocarbon closer to the chemical components of ABS than a ketone, it may both dissolve the rib material more homogeneously, preventing bubbles, and bond the paste better to the shell itself. If using DCM as the solvent, it would also make sense to soften the cracked area with DCM as well before applying the paste. I've used Acetone on a rag to clean stuff off of my hands - I would not do that with DCM. Have you tried exposing Blue-Tak to DCM to see if DCM dissolves the Blue-Tak, which would not be good? I'm not set up yet otherwise I'd be experimenting with you on this right now.

cihensley@aol.com

Teleplay:

No, I have not tested Blu-tack sensitivity to the methylene. I always soften the area to be patched first. That is what I have used the Blu-tack primarily for. To contain the solvent. The use of it is a balance. It contains the solvent. But you have to remove it carefully when the plastic is not fully solidified. Because the touch-up work is not extensive I may forgo the Blu-tack this time. I don't know what "polar chlorinated hydrocarbon" means, but I hope the methylene eliminates the bubbling problem.

Chuck

TelePlay

Sorry, I typed the wrong word. I wrote "It's not as safe as Acetone but being a MORE polar chlorinated hydrocarbon closer to the chemical components of ABS than a ketone" but typed "MORE" instead of "NON" in that DCM is a non polar chlorinated hydrocarbon -  CH2Cl2.

Polar just refers to the dielectric constant of a molecule, it's electrical charge if you will. How it reacts with other chemicals. Water, alcohols and ketones (acetone) are polar and mix with water. The chemicals below are non polar and do not mix with water.

Chlorinated hydrocarbons such a methylene chloride, trichlorethane, perchloroethane and carbon tetrachloride as well as benzene, hexane (rubber cement thinner which works well to remove glues) do not mix with water but work well at mixing with or dissolving similar substances such as plastic, some to greater degrees than others.

Chlorinated solvents (DCM, TCE and PCE) were used as degreasers for years to clean oils and greases off of metal components. Plastics are made from hydrocarbons, crude oil products. The non polar methylene chloride is more similar to the plastic than acetone and as such was probably why WE used DCM to reflow the surface of warm shells.

I have a feeling that while acetone dropped on plastic leaves a rough finish, DCM dropped on plastic may leave a smooth, reflowed finish. Uniform application of DCM would result in a uniform smooth surface - hence the method of misting the warmed shell surface with DCM. If they used acetone, I have a feeling it would just frost the surface, as we all have discovered by getting acetone on plastic by accident.

Once I get set up, I'd like to do some experimenting to see if my feelings are factual.

jsowers

Wow! Thank you, Mr. Wizard! Seriously, you make me wish I'd taken Chemistry in college rather than Physics.

I have a question or two. Is soft plastic, sometimes called Tenite,  also derived from crude oil products? Isn't it cellulose acetate? More of a "green" product, to use today's vernacular? I wasn't sure, so I thought I'd ask. It would probably behave totally differently under those chemicals if that's the case. So in your tests, be sure to try some of the chemicals on soft plastic if you can. It would be interesting to see a crack repair on soft plastic.

This is a very interesting experiment. Thanks, Chuck and John, for your input on it.
Jonathan

TelePlay

Tenite is a cellulose based material made from soft wood. Wood is also a hydrocarbon - carbon based. To make the desired product, they add plasticizers to get the properties they seek. Plasticizers are generally exotic carbon based chemicals and make the final product soft, stiff, flexible, hard at working temperatures. The difference between "soft" and "hard" plastic shells would be the chemical plasticizers added to the ABS before forming. BTW, they even add plasticizers to concrete these days, and have for years. As I think first said in "The Graduate," plastics were the future. It's a very large and wide industrial field. A research chemist working with plastics and a chemical engineer with a plastics specialty would know the many, many details of what used when and what for. BPA is a plasticizer in the news these days. That "new car" smell is plasticizers out gassing from the plastics used to make everything from seat materials to dash boards. So, the scratch and smell test on old shells has merit as does the finger nail tap for hard vs soft plastic. Finally, since the base material for hard or soft plastic is the same, I would expect methylene chloride to work about the same on each. Just a feeling, agian.