The Rot Doctor


Subject: More Transom Questions
Date: Sun, 18 Jun 2000

Hi Doc,

This is my fourth or fifth email. I purchased some of your CPES and L&L Resin to strengthen my transom. My original intent was to drill some holes in the top of the transom and inject the chemicals. However, after drilling some access holes, I found that the wood in the transom was much wetter than previously thought. As a result, I cut the top of the transom off with a Sawzall to expose the wood in side and gain a better idea of its integrity. I found that about half of it was damp and soft. Pretty sure now that this is the case for the underlying areas of the transom.

I began to hook out the soft, wet wood, but only went down a few inches (maybe 5-6). The wood seemed pretty much intact, meaning it appeared to maintain some structural characteristics, and was difficult to remove. The wood in the transom appears to be 1/4 inch plys laminated together with a glue; there are 8 plys. Much of it is no longer bonded together and is easily separated. However, each ply is difficult to remove because it still retains some integrity.

Right. What you've run into here is not uncommon. You just never know until you get in there.

Question: My thought now is to pump air in an attempt to dry the wood. Any tips on how to best accomplish this? Should I try to drill a few deep holes to reach the bottom areas? The top is drying fairly fast using the air from a 1.5 HP Shop-Vac.

What I would suggest here is drill a hole in the bottom of the transom (say a 3/8" down as low as you can get it) and tape your shop-vac nozzle to the hole first on suction to pull out moisture (this may take a day or more) and then on blow to move air from the bottom up. Then later I would pick a place on the inside or outside surface of the transom and drill into the wood and see how wet the wood is coming out with the bit. If it's still wet, tape it shut and continue the drying process.

If the wood is reasonably dry (that is, you can't squeeze any water out of it), then squirt CPES into the hole, wait a day or so, and then using a turkey baster squirt in L&L Resin, allowing the wood to absorb all that it reasonably will. Wait 24 hours and then close the hole with our Epoxy Filler. This can be sanded smooth and painted later if you wish.

This process may take some time if the wood is really wet, but the shop-vac can move a lot of air through and should do the job.

Also, because of the glue between the plys, will this affect the manner in which I apply the CPES and L&L Resin treatments?

No, the ply glue will have no effect one way or the other. After the wood is reasonably dry, you will apply the CPES from the top, and let gravity carry it down through the transom wood. Here the holes in the bottom can be an asset. At a certain point you'll notice the CPES dripping out the bottom. Catch it in a pan and then re-apply it across the top surface of the transom wood. Just keep doing this until there is very little bottom drip.

Then wait about a week.

Now, you go back with the pure L&L Resin and apply that to the top surface of the transom wood. This will be a fairly slow procedure because the resin will be absorbed much more slowly than the CPES. Just let it run through. You may or you may not see it appear at the bottom...kinda depends on how porous the wood is and how much resin you apply.

Also, the transom has developed a bow to it from the weight and force of the outboard motor. My guess this is due to the expansion of the wood from the moisture and delamination of the wood. I thought about trying to remove the wood only in the are where the jack plate (motor) mounts on the transom. After using the CPES and L&L Resin, will this result in a strong enough bond? Or is it possible that the bow will be reduced (or eliminated) after drying?

I don't think there is any doubt that the transom will be strong enough after the CPES and L&L application. But it won't remove the slight bow. Some folks tackle this problem by adding in inside 1/4" aluminum plate, through-bolted to the transom exterior. This can help remove the bow, and certainly adds strength to the whole structure. Metal fabricating shops can cut these out to you specified size.

Lastly, how wet is wet? Some of the wood is moist, meaning it will produce water if squeezed. How dry does it need to be before the CPES treatment?

Squeezed out water is too wet. If you can't squeeze out water but it's damp you're right on the margin. The dryer the better. A pain, I know, because drying takes time and you want to get going again. But a few extra days can make a lot of difference.

Now that I'm into this, I may call you next time if that's okay. Thanks once again.

Dan K.


Feel free to call. And come back with more questions if you have them.