Cleaning catalin

[wildtubes]

I have acquired an Addison model 61 portable radio which I believe is made
of Catalin. The plastic is a light brown marbled material which is the same
throughout (i.e. not painted on. I did not pay very much for this so I am a
little dubious about whether or not is Catalin (in any case this is a nice
little set and I like it). Questions:

1) Is it possible that it is catalin ?
2) If so, there is some dirt and what appears to be a tar stain on the
back - how do I clean it safely - i.e. is Windex OK ?

Thanks for your help

[Peter Wieck]

Post by wildtubes
1) Is it possible that it is catalin ?
2) If so, there is some dirt and what appears to be a tar stain on the
back - how do I clean it safely - i.e. is Windex OK ?

Possible, yes.

Catalin was a simple thermosetting phenolic resin without any aggregate. As it
was cast as a liquid, it tended to take less "sharp" shapes after casting, and
was typically less able to be machined to take threaded screws and such. There
were, often, variations in thickness of the casting as the molds, legend has
it, were destroyed at each casting. If the lost-wax-gauging plaster method were
used, this makes sense and would be well adapted for the catalin material.

Bakelite came in various colors and degrees of marblization, is also correctly
described as a thermosetting phenolic resin, but was cast as an aggregate of
semi-set catalin and (usually) very fine sawdust, carbon-black or any of
various other materials to add color and stability. The molds used were
therefore able to be used many times, so were "proper" dies with very sharp
edges. Bakelite could also be machined, drilled, tapped and carved, unlike
catalin.

Bakelite is stabile under most solvents, however they will often dull the
surface. Windex, being a combination of alcohol, ammonia and soaps does attack
wood aggregates somewhat. Paint-thinner (Naptha) is good on tar. Wood alcohol
(methanol) will also attack aggregates and dull the surface. Try any solvent
you choose on a blind spot first and see how the material reacts. You may have
to repolish the surface when you are done removing the tar.

http://members.aol.com/pfjw/page1.html

Peter Wieck
Al-Khobar, KSA

[Michael Jack]

Post by wildtubes
I have acquired an Addison model 61 portable radio which I believe is made
of Catalin.
1) Is it possible that it is catalin ?

The Addison 61 was not made of catalin. Catalin has a more translucent
or glass-like quality to it, as it started life as a clear liquid
resin with dyes added. You should be able to "pass" light through it.
Although I'm not certain what plastic the 61 is made of, I know for
certain it ain't catalin.

[Phil Nelson]

Not Catalin if that is an American model number. Only models 2 and 5 were
Catalin, according to my books. Your email address suggests that you're from
Canada; some manufacturers used different model numbers for the same radio
in Canada & the US, but I don't have any good references that would sort
that out.

In any case, Windex won't hurt any plastic that I've seen. You can also use
Novus Plastic Polish. If you're very worried about hurting the plastic,
start with Novus #1, which is the gentlest. I use Novus #2 for
cleaning/polishing virtually all plastics, including delicate dial covers,
and have never regretted it. This polish is available from Antique
Electronic Supply, http://www.tubesandmore.com/ and many other outlets.

Happy holidays,

Phil Nelson