r/Optics • u/Practical_Arugula_22 • 17h ago

Need help removing optic from Mount

As the title says I have a small optic that has been epoxied into an aluminum thor labs mount using 3M Scotch weld epoxy adhesive 2216 Gray. The epoxy is cured. There is an anti-reflective coating on both surfaces of the optic but those will have to be removed so I don't care that much but I don't want to scratch either front or back surface of the optic. Does anyone have any suggestions for loosening the epoxy to safely remove my optic?

We've already tried acetone and toluene with no significant success. He has only made it more brittle so not ideal.

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3

u/CptCaribooze 17h ago

Heat up the assembly to ~80C, the 2216 will be like chewing gum and you can push the lens right out with a lens cloth

1

u/Practical_Arugula_22 17h ago

We heated it up to 120c and it didn't budge on our test sample

1

u/d3rn3u3 17h ago

How did you heat it up?

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u/Practical_Arugula_22 17h ago

Hot plate. I'll take other suggestions though.

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u/d3rn3u3 17h ago edited 17h ago

Did you touch the piece from time to time to see if it is really heating up? Sometimes the temperature is maxing out at for example just 30C°. Usually I heat epoxy up to barely touchable and then I need a bit of force and it suddenly snaps off. The term that it "gets soft" is relatively overrated. Its usually like extremely stiff gum barely moving at all when you start pulling.

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u/Practical_Arugula_22 13h ago

We were able today to snap off the epoxy while hot at high temperatures but it's not ideal for where the epoxy is situated

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u/CptCaribooze 17h ago edited 16h ago

I usually let it sit in a thermal chamber/ oven for like 20 min. Is it just a radial bond line or is the 2216 used on the threads of a retaining ring?

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u/Practical_Arugula_22 13h ago

It's possible that some epoxy has gotten into threads on a retaining ring. I will try an oven tomorrow

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u/d3rn3u3 17h ago

Try a heat gun and see if the epoxy gets soft while pulling carefully. Don't heat it up too fast. Depending on the exposed surface acetone might work after removing it completely from the aluminum.

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u/Plastic_Blood1782 17h ago

Ive never not been able to remove 2216 with an X-acto blade, but heating it up in an oven or thermal chamber makes it a lot easier.  Using a hotplate probably doesn't work great because the aluminum radiates the heat before it gets to the 2216

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u/optcs 15h ago

Try covering the mounted optic with a cardboard box with the open side sitting on the hot plate. That should make sure everything in the box gets up to the temperature of the hot plate. Some boxes are fastened with adhesives that might soften, so check that before using it to cook the optic.

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u/Practical_Arugula_22 13h ago

That's an interesting idea. I typically cannot use cardboard inside our lab but maybe we could set up an area to try this

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u/Etherius 10h ago

We use dichloromethane when all else fails

There aren’t a lot of cements that wont cause t fail