TOPIC: Sealing bolt holes in transom

Today was spent chiseling out a bit of rotten wood in my transom. It was an ideal day for working outside here in the Puget Sound area. No rain, 50% cloud cover and lots of sunshine as the clouds would drift by. The high temp reached 52°.

I removed the Aluminum trim on the top of the transom and spent a couple of hours chiseling out the soft plywood on the port side of the transom. Next, I intend to soak it with Copper Napthanate, then fabricate a custom-fit chunk of plywood to fill most of the void. Then I'll "butter" it with a mix of wood flour and polyester resin and drive it into position. That is, unless someone has a better suggestion. No, I am not removing the entire deck (or ever the stern portion) to do a complete rebuild. Let the next guy worry about that.

But, on to the point of this post. I want to seal the bolt holes which penetrate the transom and attach the engine bracket to the transom.

A few years ago, I built an airplane which has quite a few bolts through the main spar and hold both the wing to the fuselage and the landing gear to the wing. This being a life-critical attachment, I used a bottle brush dipped in epoxy resin to brush and coat the inside of the spar holes. The bolts were coated with PVA release agent, then inserted into the holes before the resin cured.

In the future, if I need to remove the bolts, the PVA ahould allow the bolts to come out.

Is this a similar problem? I think it should work just as well on my transom, except I will use Polyester resin.



Advice?

I've always used Life Caulk. Liberally spread inside the holes and on the shank of the bolts...

I guess it makes sense there would be a marine sealer developed just for that purpose. Expensive?

Clark, My humble two cents

If the transome you are repairing is all would, I'd recommend some different materials with the same approach.

Dig out as much of the rotted wood as you can. Treat all the newly exposed wood with Smith's Clear Penetrating Sealing Epoxy. This stuff is especiually made for the job, goes way deep, and 'kills' any left over rot spore by sealing it away from air and moisture. But also allows any good wood to breath. Also treat your patch before fastening it in place.

For the 'butter', use smith's marine filler. Excellent stuff and again especially made for the job. Really easy to work with, needs no fillers, dries fast, can be drilled without cracing, sands out great, and is designed for below waterline use. Prefill the area to be patched so that when you apply the patch, any area behind it is filled in.

Cheers!

I will definitely Google Smith's and check it out. Thanks for the lead - it sounds exactly what I need.