How to know when your coating/potting is cured?

[BlaineW]

Not sure if this is the right subforum, but as a mechanical guy I was hoping someone could point me in the right direction.

When using a temperature cured two part silicone potting or 1 part conformal coating what methods can be used to verify/validate a cured state?

I've tried technical data sheets and manufacturers but they tend to stick to the "We recommend all customers test to their own specifications" mantra.

Most documents say it is considered cured when it reaches 90% of its optimum properties...but those properties tend towards tensile strength, dielectric strength, hardness...all which seem hard to measure and make me nervous.

Thanks for any guidance.

 

[Oingo1]

Hi - I think that the most accurate way is by chemical analysis, although this is not entirely practical as a quality control tool. Basically, you need to know the chemical reaction that occuring to cure your coating, and then analyze a free film for residual functional groups that haven't been consumed by crosslinking. There are many ways to analyze a free film, but most likely start with FTIR or similar. There are many ways to make a free film, but you generally do it in the lab not on line. So while this is generally accurate, it's not always practical. Hope that helps. --