Subject: Outboard Bracket
Date: Thu, 24 Oct 2002
I am installing an outboard motor bracket on my new boat. My question is?
There will be several holes drilled into the transom for the bracket
mounting, plus larger holes for the controls, steering, fuel, etc for
I would like to treat these holes to protect the the layers of
plywood prior to installing the bolts. Any suggestions for treating
the wood before anything is mounted to keep out moisture down the
After you drill the holes, treat the exposed wood thoroughly with CPES (Clear
Penetrating Epoxy Sealer). Dab it on the wood and allow the wood to
absorb all that it will. Our smallest unit of CPES, the 2-pint unit
should be sufficient. The CPES will coat all wood fibers with epoxy
resin. The wood will not rot in the future. If you wanted to be obsessive
about it, you could wait a few days and then come back and re-coat the
wood surfaces with our Layup & Laminating Resin to totally seal it off.
All our testing, however, shows that wood treated with CPES alone will
If there are mounting brackets that are tight-fastened, we suggest using
a 100% polyurethane sealant, such as 3M™ 4200, to seal the
enclosure. Ideally, you apply the 3M™ 4200, then screw the bracket
down to about 80%, allow a few days to pass, and then screw the bracket
down the remaining 20%. This in effect creates a gasket that will not
Hope this is helpful. The application of the CPES is the most important
step in protecting your wood. Come on back if you have additional questions.