> Even the alcohol can leave impurities behind that will affect the epoxy.
> If you find a brand that works, stick with it.

Hi Don

Just a quick comment on "impurities" in our solvent cleaners (alcohol, acetone, whatever).

In a discussion with the technical rep from West Systems products, he pointed out that while it is possible to inadvertently contaminate a container of solvent by "backwashing" something into it, the major source of contaminates comes from the rags we use or the surface we are cleaning. Not the solvent its self.

Soap residues (which are lard based) get dissolved out of the "clean" rag and deposited on the surface being cleaned. Much of the cloth we use as rags is made with a percentage of synthetic fiber. Acetone has a bad reputation because it can dissolve many of these synthetics and the residue left on the surface can cause problems.

I have often wondered if I used enough cleaner to dissolve ALL the contaminate and a rag big enough to actually lift/carry the contaminate off of the surface I am cleaning or am I just spreading the dirt in a nice thin layer :-( Does the expression "fish-eyes" mean anything to you?

BTW, what do you do with the cleaning rag after you have used it? Use it again? Been there, done that - had the fish-eyes to prove it.

I have become much more careful (paranoid?) with my surface prep. I do an initial wipe down to remove the most of the contaminate and then go back with a fresh cloth a second time - results have been good.

While it is possible that there may be a chemical incompatibility between products, look at your process as well.

Hope this helps.

Hank