The Rot Doctor


Subject: engine bedding (transom rebuild)
Date: Wed, 31 Jan 2001

dear dr.rot,
i have just about completed my transom rebuilding job, just waiting on the chemicals i ordered from your website. i have replaced most of the rotten wood with new wood and i plan to use the 2 part method to bed the new wood in (cpes and l & l resin after) my question is, after everything has cured and i'm ready to drill my new holes, is there something i must do to prevent water intrusion again? this boat had 4 bolts mounting the motor to the transom, no seals, just some silicone which obviously didn't work very well.
can you help
dave c.


After you drill your new holes, immediately treat them with CPES by just swabbing it in there. Go ahead and bolt things down, using as a sealant a polyurethane sealant. Apply the sealant, and then bed things down to about 75%. Wait for a few days (if you can) while the sealant firms up, and then bolt down tightly. This way the sealant acts as a kind of gasket.

Don't use a silicone sealant! We don't like silicones because we don't think they seal that well. They dry quickly and are cheap to make, so they are heavily promoted. We sell a 10 oz cartridge of pure polyurethane sealant 3-M's 4200.

Okay? Come on back if you have more questions.