1
$\begingroup$

The reason for my question is I'm planning to use DAP Rapid Fuse general purpose (Ethyl Cyanoacrylate) adhesive on a few microscope components and do not want the outgassing to effect the glass optics. So knowing the outgassing characteristics of Ethyl Cyanoacrylate would be very helpful. Thanks

$\endgroup$
1
  • $\begingroup$ What does the data sheet say? Have you asked the manufacturer as this is a very specific use and they likely have a technical sales dept. $\endgroup$
    – Solar Mike
    Dec 9 '20 at 5:02
1
$\begingroup$

Almost all chemical processes slow down as you have less chemicals that can react. Same is true for CA glue. As it reacts with water, it becomes harder and less permeable to water and itself. You can speed up the process by heating, adding more water. Process does not hit a state 'all 100% components have reacted' once clock shows that 10 minutes have passed. It will never reach 100%.

Ideal preparation process would be to soak the part in warm water for hours. Then heat and dry it at temperature thats just below lowest plastic decomposition temperature in your assembly. Then put it in a vacuum for hours and allow most of the outgassing to happen there, rather than in your testing equipment. Outgassing, as all other processes, is fast initially and slows down as less material is left. You can also use dessicant (Si2O) or even getter (aluminium) in your testing equipment, to make the vacuum better.

$\endgroup$
1
$\begingroup$

It would depend on the precise mechanism of cure.

If the Gibbs energy crosses the zero line and reaction stops, then yes, outgassing will also likely cease.

If however, the reaction is limited by the availability of products, then the outgassing rate will tend to zero but never reach it as time moves to infinity.

You can use an instrument called a residual gas analyzer (RGA) to check for the presence of outgassing products.

If preventing outgassing is mission critical, then you need to verify with RGA, or some other means, that it doesn't occur, even if the manufacturer says it doesn't.

Regardless, I'd suggest the first step would be to call the manufacturer and see if you can talk to one of their scientists and see what they say.

$\endgroup$
1
  • $\begingroup$ Great answer. I've often found that contacting the manufacture is a great way of obtaining authoritative technical information. $\endgroup$
    – Eric S
    Dec 9 '20 at 17:45
0
$\begingroup$

I spoke with the manufacturer, telling them I’m using a very thin coating to join small mirrors and metal brackets and the amount of adhesive used for each mirror/bracket will be about .05ozs. They said if there is no hazing around the edges the outgassing will likely stop after about 45 minutes. I told them I could let it cure overnight If there is hazing. They said 12 hours should be sufficient to ensure outgassing has stopped.

$\endgroup$
1
  • $\begingroup$ So my original comment to contact them bore fruit... $\endgroup$
    – Solar Mike
    Dec 10 '20 at 6:30

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.