The Rot Doctor


Subject: question (CPES as a primer)
Date: Thu, 20 Jul 2000

Hello ,I just talked to a tech at Interlux paints . He told me if I use the cpes, everywhere I used it I would have to use a diff. primer than I would use on the rest of the boat. If not mistaken I read that paint would stick better to the cpes coated areas. Does this sound right? He said any where I used a resin I would have to use a product called epoxy barrier coat # 404-414. Hate to take up your time but I really want to do this right, thanks David M.


When the paint manufacturers hear the word "epoxy" they are thinking of a standard epoxy resin, which is thick and usually produces a "blush" (ours doesn't) that retards the adhesion of paint. Hence the epoxy barrier coat.

CPES, on the other hand is very thin (like diesel fuel) and penetrates INTO the wood. It leaves a slight sheen on the wood, but because this is the purest of the pure epoxies there is nothing there to retard the adhesion of paint.

We have done extensive testing and know that 1) there is better adhesion to a wood surface by ANY paint after the application of a coat of CPES, and 2) this adhesion becomes even stronger if the paint is applied while the CPES is still tacky (15 minutes to 45 minutes, depending on temperature and air movement. No prime coat is required, unless you want to sand the surface to get an absolutely mirror-smooth finish coat. It is my personal opinion (not tested) that the one-part polyurethane paints adhere even better.

You CAN use the #404-414 barrier coat if you wish, and it too will adhere strongly to the CPES-treated surface. But it's not required.

Okay? Hope this helps you. Come on back if you have additional questions.