View Full Version : Best epoxy for the job.

03-09-2009, 12:04 PM
I have a 63 "White" lapstrake runabout that leaks. She's pretty tight but I trailer this boat she never really gets the chance to swell up ,although I don't beleive this boat relies on swelling as much as some other wood boats do. I have replaced almost every frame "rib" from stem to strern and as I said shes pretty tight. I can't afford to have the bottom replanked so I'm going to do what I'm sure will get me in some hot water with a few of you on this site. I want to glass the seams from the stem outside just to the water line.This boat flex's quite a bit I'm sure. I have used the west system before with great results in a very ridged fixed application but am I correct that it is one of the more ridged epoxies curred and would I be better served using a different product for this applicacion. Plus it's exspensive as heck. I'm sure I'm going to hear it on this one but I think this is the lesser of two evils if I'm going to keep this boat alive. Short question is :What's the best epoxy for this application. Thanks in advance and I look forward to your input.

Bob Cleek
03-09-2009, 12:31 PM
None at all. Wood shrinks and swells. Epoxy don't. Your boat will still leak, and be full of epoxy. When the planks push against the hard epoxy, they will spread even more and it will leak more. If your boat is riveted, you may be able to tighten up the seams a bit by tightening up the rivets. Just back the heads and give them a few taps. Alternately, if you must put anything in the seams, you should use a decent polysulfide.

Mad Scientist
03-09-2009, 12:40 PM
Gosh, I looked, left, then realized that I was 'viewer #1', so I felt compelled to help...here goes, until the experts arrive!

My understanding is that epoxy is incompatable with traditional lapstrake (but works perfectly with plywood lapstrake).

How is she fastened strake-to-strake? Might be a possibility that fastenings have worked loose over the years.

One last thought - is she leaking between the strakes, or through some other area? Is there a keel/garboard strake seam, or a transom/hull seam?

If you need to resort to 'goo', I suspect that something less rigid than epoxy might be appropriate.


(and Mr. Cleek responded before I finished composing my response...)

03-09-2009, 12:45 PM
If you need to resort to 'goo', I suspect that something less rigid than epoxy might be appropriate.


Ditto this suggestion. There is a local trad lapstrake builder who uses a polysulfide caulk - I think - for his lapstake dinghys that spend a lot of time out of the water.

Scott Rosen
03-09-2009, 03:30 PM
I've never done this before, but it seems logical to run a bead of polysulfide along the seam on the outside of the hull. But wait until the boat is good and dry. It's a temporary fix at best.

03-09-2009, 08:11 PM
This is a plywood lapstrake.I understand wood swells and shrinks as it gets wet and dry's but if this boat didnt leak it wouldn't get wet right? And as I said this boat is trailered and lives in a building when on shore so it's stays dried out most of the time.What is "polysulfide"?? If it's some product like sekaflex 5200 I already tried that and it didn't work.I have seen other lapstrake boats that have been glassed over and they seem to be fine.They dont leak and there not rotting either.They are also trailered boats that don't live on the hook.I have made small repairs elsewhere on the boat the epoxy seemed to bond well.None of them have failed and it's been several years.Maybe i'll just stick with the West System as it hasn't failed me yet.Also this boat swims in salt water only if it make a difference.

03-09-2009, 08:18 PM
Jeff, didn't realize its plywood. Doubt if other posters did, either. In that case can't think of any reason why you shouldn't epoxy glue all the planks together at the lands. That's how the vast majority of ply lap boats are held together. Add fiberglass if you like. My favourite epoxy is RAKA but I'm sure WEST or any of the well known brands would do fine.

03-11-2009, 04:15 PM
simply paint it with sanitred permaflex.
Permaflex is a flexible rubber polyurethane
It wont leak anymore.


I coated my boat and it has worked out fine.

since it is a runabout, you could easily flip this boat and the permaflex will easily soak into all the seams.
The boat will also be much stronger.