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dsterli1
07-03-2008, 07:44 AM
I am painting the bottom of my brand new to me 1967 Thompson. I noticed on spot at the keel where there is minor damage to the plywood. The very outside layer has worn through. Structurely it is not rotted and is still solid. My question is; should I just paint it or should I apply a coat of epoxy to the affected area?

esingleman
07-03-2008, 08:10 AM
Can you post a picture?

JimD
07-03-2008, 11:08 AM
Welcome to the forum, dsterli1. In general, I would treat it the way the rest of the keel is treated. If there's no epoxy on the keel anywhere else no need to start now. If its a noticable gouge you may want to fill and fair it, though.

thebrushand
07-03-2008, 11:17 AM
Judging by what I have unearthed on our boat in the last couple of days, you will need to do more than just brush a lick of epoxy on your troubled area for a professional long term solution. From what I can see of repair work done recently for us, the penetrating epoxy looks nasty but doesnt penetrate worth a light if brushed on to damaged wood.

I suppose if you could drill holes and inject it to saturate the troubled area, (like the sample pieces in West Marine) you may be on to something, but I am looking at a treated piece of wood that should be in the trash, not on my boat - behind the thin layer of epoxy the wood is untouched and still as spongy as - a sponge?So instead of solving an issue, it gives a false sense of security and lines you up for a lot more work later on.

In fact, poorly applied epoxy may make the problem accelerate quicker than if it weren't treated. ie From what I have seen of a "treated" frame (where epoxy was ladled on to 3 of the 4 soft sides), what I am looking at is a rotten piece of timber coated with a hard sealant on 3 sides, and the untreated side is like a door left open for dry rot to enter in and progress in comfort away from prying eyes.

Todd Bradshaw
07-03-2008, 04:32 PM
I don't believe he mentioned anything about the wood being rotten or otherwise structurally unsound. You have to figure that if you have worn either deeply into, or through one or more of the veneers making up the plywood, then you have almost certainly exposed some end grain in that area which was never meant to see the light of day (or water) and which becomes a liability. This needs to be sealed whether or not you choose to replace the worn-away portion. The original finish of paint or varnish is one option, but there is no question that the best moisture barrier that you can apply to seal this plywood end grain is epoxy resin. A couple of thin coats of unfilled resin is generally adequate for doing this, but some woods will take more coats as it really just keeps sucking the resin in. This is your chance to make sure that it's truly sealed and not going to be sucking in water later. Once sealed, if you have some sort of crater which needs to be filled, it could then be done with either a resin/filler mixture or possibly wood glued-in with more epoxy. Fair the patch level with the surrounding good wood and finish it to match the rest of the hull. It's probably also worth trying to figure out what caused the initial damage and deciding whether you need some sort of abrasion barrier in that area to prevent the problem from recurring.