Subject: Boat Deck Restoration
Date: Fri, 31 Mar 2006
I purchased a used boat and tore out a lot of the decking due to rotting. I purchased Marine Grade Plywood and painted it with a water sealer. I am worried the oily feeling that is left behind will hinder my sealing the wood to the remaining deck. I have been considering fiberglassing where the edges of the new wood meet the old wood to create a waterproof seal. Will CPES penetrate the water sealer and allow an adhesive surface?
You're going to have a problem getting any resin, including CPES, to get through the water sealer. The water sealer was probably a petroleum-based sealer and these always cause problems with penetration/adhesion of the polymer resins, such as epoxy and polyester. I'd suggest asking the manufacturer of the water sealer how they suggest you remove it from the wood, at least in those areas where you want to fiberglass.
So, the answer to your question is no, CPES will not effectively penetrate through the water sealer. You need to remove the sealer and get to a clean wood surface.