Posts: 202
Location: Angola, IN | When I drilled a test pilot hole in my transom, I could see that the wood core was wet, but it didn't appear to be rotten and/or disintergrating. Usually the wood appears to be turning to dirt when it's completely shot. Mine still looks like wood. Just wet.
So on the transom, there is a thick layer of fiberglass on the outside, a layer of wood inside that, and then usually a thin skin of fiberglass on the inside of the transom to act as a water barrier. I drilled my test hole through the inside, so that I went through the thin skin, and then through the wood, and stopped when I hit the thick fiberglass. You can tell by looking at the shavings coming off your bit.
You're going to do the same a bunch of times, so get a drill bit stop so you can drill the same hole depth many times quickly. Then I used a 1/8 or 3/16" drill bit and drilled a bunch of holes from the top to bottom, port to starboard on the inside of my transom. Two holes were never more than 1" apart. I drilled a couple hundred holes. Then I got a squirt bottle with a 90 degree neck on it, and filled it with 100% Acetone. I squirted all the holes full of acetone. Let the Heater work on evaporating all the solvent. Maybe wait a few hours, and re-fill the holes again with acetone. I did this about 5 times. The acetone will dry the wood out....getting rid of all the water.
Then I bought a gallon of West Sytem Epoxy and a pint of their slow-catalyst hardener. I thinned the epoxy out by about 20% with Acetone and I did NOT add any hardener. I think used a syringe and squirted all the holes fill of thinned out epoxy. Let it sit for about 30 minutes. The plywood core will soak this epoxy right up. Then I did it again. Wait a bit. Do it again. Wait. I did this until the wood was saturated with epoxy, or dang close. You can tell when you squirt the thinned epoxy in, and it immediatly runs out of the hole. But do this step at least 3 times and wait at least a half hour before repeating.
Then I mixed up a batch of straight epoxy and TWICE the amount of slow hardener (because it's gotta catalyze the epoxy in the plywood) and quikcly brush/spread the epoxy over the inside of the transom. Let it harden. You can drill a quick test hole when it's all cured near the top of the transom to make sure all the epoxy has catalyzed.
This is what I did. Worked great. However, if the core is all the way gone, I recommend Seacast and/or putting a steel/aluminum plate on the transom to shore it up.
Steve |
