Maybe you can help

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Janne

Sent off - Not allowed to play
Feb 10, 2016
12,330
2,293
Grand Cayman, Norway, Sweden
This is a bit of a long shot, but I have this problem.
I need to remove a coat of sticky paint ( oil paint?) from a piece of plastic looking eye piece.
I say plastic, it is hard, so could be Bakelite, or Cellulose or something?
What solvent should I try?
Acetone might be to strong. I must not destroy or damage it.
It is manufactured in UK in WW2.

Any ideas?
 

Broch

Life Member
Jan 18, 2009
7,981
7,757
Mid Wales
www.mont-hmg.co.uk
If it's military I doubt it's oil paint as even in WWII the MOD required petrochemical resistant coatings (you should see the hoops we have to jump through now to get surface coatings accepted). If it is oil paint I would try turps or a white spirit first - that shouldn't damage plastic at all. Bakelite can handle most solvents in my experience.
 

Tengu

Full Member
Jan 10, 2006
12,776
1,510
51
Wiltshire
Humph. You have a problem in two parts;

What paint?
What thing painted?

Old plastics is a nightmare for museums; its frangible, complex, and often the recipe is long lost so you dont know whats in it.

https://www.modip.ac.uk/

Have some guides as to dealing with old plastics. I frankly doubt they will be of use but you might like emailing the staff; they may have some suggestions.
 

Janne

Sent off - Not allowed to play
Feb 10, 2016
12,330
2,293
Grand Cayman, Norway, Sweden
I do not know what kind of paint it is.
It is black (matters not:) )
Sticky surface, but hard underneath. I think the stickiness is an age thing. Does not leave any black residue on your fingers.

It is a part from British made ‘ Telescope Stereoscopic No 1B MK1’ made in 1945. Reading from the ID plate.

It is a military device, called Donkey Ears.

The part is the ring which you put your eye against on the ocular.

The part of it which is not painted is hard and black.

I do not think it is original paint from -45 as it would not make any sense to paint a black part black.
The rest of the binos have been painted several times over the years, I could see at least 3 layers of slightly different shade ( of green) when I took it off with some nasty paint removal.

The problem is, I can not destroy it, it would be very difficult to make a new part. In the plastic there is a threaded brass ring incorporated.

Thank you for the link, much appreciated!
 

Tengu

Full Member
Jan 10, 2006
12,776
1,510
51
Wiltshire
One gets by.

Glad to attempt to help; I am very much afraid even MoDiP might not be of use; its a ticklish subject.

But if anyone knows about old plastics, its them.
 
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Fadcode

Full Member
Feb 13, 2016
2,857
894
Cornwall
Janne, when I was a kid and i would come in with tar or oil on my hands my Mother used to clean it off with margarine,( we couldn't afford butter), I would suggest scraping a bit off and then see what reaction the margarine has on it, also the margarine being smoot and creamy is unlikely to cause damage.
 

Janne

Sent off - Not allowed to play
Feb 10, 2016
12,330
2,293
Grand Cayman, Norway, Sweden
I will try that! Oil too.
I have browsed the ‘net quite a bit, and found that (during WW2) much ‘plastic’ was replaced by Vulcanite.

I have another pair of the Donkey Ears, I intend to keep those in original state, but with a slightly chipped eye piece. Same sticky paint.
Will scrape off some and experiment.

Wife bought back some truly exciting stuff, including two heavy duty ex mil ( Swedish or German) Zeiss tripods....

All other projects are now put away!
:)
 

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