The Rot Doctor


Subject: my old Chris Craft (plywood problems)
Date: Sun, 01 Oct 2000

I was just given a '67 Cavalier and I convinced that your product line is the means to make it seaworthy again.

The main issue is this: The above-waterline hull was sanded to bare plywood two years ago and then left exposed to weather. It is basically sound, but the plywood surface has a porous raised grain and there are even a couple places where the corners of plywood edge are staring to delaminate. I believe it to be worthy of salvage though. I haven't actually discovered any serious rot yet, but I think your product is the best pre-emptive move I could make.

So, I apply the CPES and then do I need to cover that with a layer of Lay-up resin or do I go straight to the hull paints? Should I also be considering CPES on the interior of the hull?

On the general flat surface, I'd suggest sanding it down smooth first, and then coming back and applying 2 coats of the CPES. On the first coat you can figure on coverage at about 200 sq ft per gallon, and on the 2nd coat at about 400 sq ft per gallon. Where there is delaminating on the ply corners, I would poke a little of our Layup & Laminating Resin in there after the CPES (flow as much CPES into these delam areas as you can) and then, if possible, squeeze them shut, maybe with a clamp, small brass screw, or brass brad.

Then paint the whole surface with a one-part polyurethane paint, a couple or more coats. There is no need to use a primer over the CPES, unless you want a sandable build so that you end up with that glassy smooth surface.

The L&L Resin over the whole surface is probably not necessary, unless you find some evidence that the ply is actually too thin. If this were the case, I'd suggest that you apply one thin layer of glass cloth (say, 8 oz) bedded in the Layup & Laminating Resin. Then you'd have to use an epoxy primer to build the smooth final surface for painting.

The deck is covered in a heavily textured paint that is starting to peel back at the edges. I cannot tell if it was original issue for the boat or if it was simply a shoddy maintenance tactic. My inclination is strip that off and go with a clear varnish sequence wherever possible. (I love the warmth of wood over painted surfaces) Do you have any resource people in Portland Oregon that I might be able to pick the brains of?

Lastly, can you recommend a brand and quality level of hull paints? I expect only to take it on the river here, but it might be good to have salt water resistance anyway.

As noted above, we believe the one-part polyurethanes adhere particularly well to a CPES-treated surface. There are several available in marine stores, and we have no special preference between brands.

Looking forward to joining your family. Thanks for your time. Marshall C.


I do think the CPES will solve your problem. It will give a very superior base coat for paint and will give the wood good protection against rot in the future.

Come on back if you have additional questions.