|[AMRadio] Paint Filler|
jsternmd at att.net
Mon Jan 6 20:04:47 EST 2014
Perhaps there is a difference between catalin and bakelite used for common
vintage radio knobs and boards versus jewelry. Collector quality bakelite
or catalin jewelry - some which sell for more than KWS-1 -- can be polished
aggressively to restore the original colors which oxides dull over time. My
wife (the 40+ years of collecting expert ) claims never to have heard of
over-polishing any bakelite or catalin at risk of breaking through any
'thin' finish. Further you can buy on Ebay rods, blocks of various catalin
and bakelite and it is apparent that the "finish" and color(s) is through
and through these few inch thick blocks . Perhaps the phenolics used in
jewlry was of a different quality or process than radio knobs but I would be
surprised as bakelite and catalin jewelry were mass produced for the "poor"
folk. The phenolics absorb and release moisture during the process and are
more susceptible when exposed to heat as in radios. I found an interesting
article from a 1918 Aeronautical journal discussing the benefits of
manufacturing propellers with a bakelite veneer over wood. Real interesting
reading- can be found by Google.
Well let's go back to radios...
From: amradio-bounces at mailman.qth.net
[mailto:amradio-bounces at mailman.qth.net] On Behalf Of W. Harris
Sent: Monday, January 06, 2014 12:59
To: amradio at mailman.qth.net
Subject: Re: [AMRadio] Paint Filler
You say "Bakelite or Catalin". They are two different plastics. Bakelite is
a thermoset resin that is cured under heat and high pressure and does
contain fillers. The shiny finish on Bakelite is very thin and if you polish
through it it is gone. Catalin is a poured resin that does not contain
fillers. Catalin out gasses over time and shrinks. That is why you see
cracks in Catalin radios usually around the screws holding the cabinet to
> Message: 3
> Date: Mon, 6 Jan 2014 10:16:03 -0500
> From: "Jerry" <jsternmd at att.net>
> To: "'Donald Chester'" <k4kyv at charter.net>, <amradio at mailman.qth.net>
> Subject: Re: [AMRadio] Paint Filler
> Message-ID: <email@example.com>
> Content-Type: text/plain; charset="us-ascii"
> I use the lacquer sticks as well. One comment on the bakelite knobs
> as my wife is an expert bakelite collector. True bakelite or catalin
> has no "filler" it should be bakelite through and through as I believe
> Dakaware knobs are made. It would have been a difficult and expensive
> process to apply bakelite over a sawdust filler. There are lots of
> bakelite polishes available the best (also used for testing if bakelite)
is simechrome brand.
> I can take any Dakaware knob and polish it to any grade of luster usually
> with elbow grease sometimes a dremel buffer wheel. I think one problem
> that bakelite was replaced for knobs around the 1950-1960's so many
> later knobs were made of a duller non-bakelite plastic and given a paint
> final luster.
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