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Old 19th Jun 2014, 9:31 pm   #1
Tractorfan
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Smile Bakelite - can it be absorbent?

Hi,
A couple of years ago I bought a new Edison screw to bayonet adaptor which was made from a modern bakelite type material. It was used in a brass lamp holder and had an LED lamp screwed into it.
T'other day I went to remove it and found that it was now a very tight fit in the holder. It was in an outdoor environment, but not exposed to the weather and has not been heated by the lamp.
I'm curious as to how it has expanded just a tiny bit, but enough to get stuck in the holder.
Can thermosetting plastics be absorbent?
Cheers, Pete.
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Old 19th Jun 2014, 10:09 pm   #2
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Default Re: Bakelite - can it be absorbent?

Bakelite has a wood powder filler added to it which swells when exposed to water and ruins the finish.

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Old 20th Jun 2014, 7:56 am   #3
mole42uk
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Default Re: Bakelite - can it be absorbent?

I have had the same effect with Weller TCP irons becoming a very tight fit into the holder on the stand. I thought it might be heat, but that part of the handle doesn't get hot.
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Old 20th Jun 2014, 8:10 am   #4
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Default Re: Bakelite - can it be absorbent?

Bakelite does swell if stored in a damp environment, I have a 1930's GEC radio that was stored for many years in a damp shed, the surface of the cabinet was no longer smooth, and I had a hell of a job removing the back screws due to the swelling.

As mentioned, this is due to the wood filler material expanding.
I had no other option than wet sanding the cabinet to get it smooth, but even after buffing with rubbing compound it would not shine, in the end I sprayed it with lacquer to seal it and restore the shine.

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Old 20th Jun 2014, 10:03 am   #5
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Default Re: Bakelite - can it be absorbent?

I have one of those mid '60s globe radios. The 3" x 3" battery compartment cover under the base plinth is about 3/16" thick bakelite. The base is flush with no feet so easy for damp to set in. It had swelled so much that it took great effort to remove it to fit batteries. Having got it out, I filed all edges to ensure easy removal in future
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Old 20th Jun 2014, 11:03 am   #6
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Default Re: Bakelite - can it be absorbent?

Quote:
Originally Posted by mole42uk View Post
I have had the same effect with Weller TCP irons becoming a very tight fit into the holder on the stand. I thought it might be heat, but that part of the handle doesn't get hot.
"A tight fit": ditto here. The sleeve of the iron will get hot, so the circular metal plate at the base of the handle will get hot, too. When the iron is resting in the holder, the iron will still be running hot, thus heating that plate, thus heating the holder.

Al.
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