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gray duck
09-28-2007, 12:50 PM
5200 vs epoxy for centerboard trunk and keel in small boat like the shellback I'm building???? if 5200, do you rec putting it on bare marine ply or sealed (ie coated with epoxy first)? input much appreciated.

Thorne
09-28-2007, 02:39 PM
Bonding what to what? What materials and coatings on the CB, CB case, and hull?

As far as I'm aware, you always want to seal marine ply with epoxy, particularly any part that will be exposed directly to water. The edges are of course the most critical part, as are any holes for fasteners. Then you can use whatever glue or sealant is correct.

The CB trunk in my dory skiff was built from oak, sealed with CPES and red lead. The CB is marine ply sealed with CPES and several coats of glass and epoxy. The hull is 7/8 fir, sealed with CPES and red lead.

I used large bronze screws through the hull into the CB case sides and ends, backed by a flexible sealant (Vulken116) between the CB case and hull, which seemed like a good idea at the time -- I was concerned about hitting something with the CB and cracking any hard glue fillets/lines.

However I get some leakage when the CB is down, so screws plus an epoxy fillet would probably have been a better idea.

gray duck
09-28-2007, 09:55 PM
thorne - thanks for the reply - the trunk bedlogs are WO and the plywood is marine mahog - You would screw and epoxy fillet or 5200?