Rot Doctor


Subject: CPES + Topcoat? Follow-up (CPES under Sikkens Cetol)
Date: Mon, 10 Jul 2006

I’ve got a follow-up question to the Q&A from the “Homes” FAQ section of your site (CPES + Topcoat? posted 25, Oct. 2003). It talks about a redwood table. Instead, I’ve got a vertical surface - a southern exposed Honduran mahogany front door and want to apply the lowest maintenance, clear sealer available. I already bought one: Sikkens Cetol Door & Window exterior coating because I have heard good things. Is there one that better? If you had one I’d buy it and be done!

Sikkens says their product is a “high solids alkyd”. Will it work better with a base coat of CPES? This is my guess but I don’t know what alkyds are. Are high solids alkyds the same as urethanes? Will you share any opinions you have on Cetol and tricks to working with it?

I have used your epoxy filler and CPES to restore the decorative window trim on my historic Capitol Hill house in Washington, D.C. I have been so pleased with the results - the filler doesn’t separate from the wood as Bondo or other wood fillers always seem to do.

Many thanks.


CPES cannot be used under the Sikkens products. They must establish their own penetration of the oils/alkyds (no, they are not the same as a urethane). The big advantage of the Sikkens products is their ease of application, and the relative ease of recoating. The alternative, which produces a more lustrous and beautiful surface, are the marine-grade varnishes. But the varnish must be at least 5 coats and, generally speaking, should be lightly sanded and re-coated annually. CPES is often used as the prime coating for the varnishes. It increases the durability of the varnish.

The Sikkens or varnish issue is a subject of discussion among the boaters. Some can live with the diminished appearance of the Sikkens because it is easier to apply/maintain...others insist on the deep, shiny tones and gloss of the varnished surface.

You take your choice.