The Rot Doctor


Subject: Drying out a Crusader
Date: Sun, 14 May 2000

Hi Doc!
Back for more...ready?
I decided to de-tarp my 30' '66 Crusader. I have only a small tarp set up as a "sun"brella over her cockpit. That will keep 90% of rain out.
Although weather is still quite "iffy", I think the tarp is retaining moisture/humidity and detracting from getting her "dry" prior to CPES.
One side's bare wood now and, with a bit of rain, water seeps out, from the interior, after running down from her deck above. So, yesterday, in about 2 1/2 hours, I removed about 138 bungs and screws and removed the toe rail along her deck, exposing the top hull plank edges. That's were the water was getting in. The toe rail, it seems, was bedded with nothing but a strip of canvas. Well, at least nothing remains of any other bedding.
Item: I've seen in replys to others, that you have a favorite phrase: "As dry as possible"
Question: How can one determine that? Dry her for a couple of years? :-)

What we're really meaning here is that although the wood might contain some moisture, we don't want it wet. If you were to use a moisture meter we'd like the percentage under 20%, and definitely under 30%. In the real world, it means that if you can press hard on the wood and water seeps out it's too wet, if not it's okay.

Sometimes just uncovering as you did and then having a day of sun will dry the wood out a lot more than you think. CPES has some alcohols and acetone in it to drive out water.

No, seriously...I assume that CPES will not drive water/moisture out.

It will some, actually.

So, I need some advice. I was thinking about 3 to 5 days of no rain/dry atmosphere/sun before beginning...with as much moisture entrapping paint off of her gunwale deck.

That would be fine, I'm sure. Even 2 days would probably do it perfectly, and, as noted above, you might squeeze by with one. We're very good at this out here in Seattle!

Item: When I put in a foul-water pump out port, the side deck is at least 2 inches thick. During the installation, I hole-drilled down about an inch (maybe a bit less) before running into moist wood.
Question: Would CPES tend to get that deep anyway?

Not through good wood, but possibly through seams.

Assuming "solid" wood, what is the penetration of the coating?

CPES penetrates only about a mm through new solid wood. Through old wood it will penetrate different distances, depending on the absorbency of the wood. CPES goes where water goes, and where water goes rot can develop. This what makes CPES so effective: It follows the same paths and where it finds soft wood it is absorbed. It hardens the wood and reduces its ability to absorb again enough water to allow biological activity.

Item: There is a borate rot spore killer on the market (got some). Mixed with warm water, sprayed on and allowed to dry. Instead of encapsulating spore, it poisons the food source.
Question - Any problem using this first before CPES that you know of? Probably an un-needed extra step?

Yeah, basically you're right about it being an un-needed step. The borates will work but they are leached away over time by moisture, and, of course, they do nothing to restore any structure to the wood. We tell folks that if you feel you must use borates then do so first, allow the wood to dry, and then come back and apply the CPES. I DO think the borates are redundant when CPES is going to be used, but is you want to....

The borates are best when one has an extremely large area to treat, and one that is not subject to the same moisture conditions as a boat -- such as an attic. Or sprayed around the inside of a hull.

That should be about it. (Yeah, RIGHT!!!)


Hey! We don't mind answering questions. The more you know the better.