The authoritative public forum
  for Metal Finishing since 1989
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How to prep and bond Invar to epoxy panels

Q. I need to bond an Invar plate to carbon reinforced epoxy blocks.This is for a thermally stable platform I'm building for a telescope. Can anyone tell me the proper surface prep for the Invar plate to maximize adhesion using room temperature epoxy adhesive ⇦this on eBay or Amazon [affil links] ? If chemical treatment is the best method, I would appreciate a description of the procedures, chemicals, and pitfalls.

Thanks,

Chris Dumlao
engineer/hobbyist - Pleasanton, California, USA
2000

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Q. I recently found a product called "Caucciu" in Italy, that translates as "Invar Rubber" and on doing a web search I found you and I am hoping that you may be able to direct me as to what sort of manufacturer/company I should be looking at to obtain this product. I live in Sydney, Australia. Any help you can give would be most appreciated. Regards, Peter Kissner - Sydney, NSW, Australia 2002 A. Hi Peter. I don't think "Caucciu" has anything at all to to do with the metal "Invar" :-) I believe the word just means "natural rubber", but that what happened is that in Italian it is an 'invariable' noun (same in plural form, as in the singular) noun ... and that someone may have just seen the abbreviation "INVAR" when they looked it up in the dictionary. Good luck. Regards, Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey February 2014

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Etching Super Invar 32-5 for Bonding

Q. Does anyone have suggestions on an etchant solution for super Invar 32-5? If so, please include solution composition, immersion time, and temperature of the solution.

Greg Wasielewski
Aerospace - Palo Alto, California, USA
2006

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Prep before BR-127 Primer on Invar

Q. We recently received 2 RFQs from different companies to apply BR-127 over Invar.
One vendor wants us to clean the parts in an alkaline cleaner and apply the BR-127 afterwards.
The other vendor, wants us to use the FPL etch and then apply the BR-127.
We are used to applying BR-127 over aluminum and other substrates, however, I believe that the proper procedure should be grit blast at low pressure with aluminum oxide media, followed by sol-gel treatment and then BR-127.

I would like to hear from the forum their opinion

Martiroz Avoyan
- Los Angeles, California - USA
July 2, 2020