How to use System Three Epoxy

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Gary Hartleben
Posts: 9
Joined: Fri Jun 13, 2008 11:12 am

How to use System Three Epoxy

Post by Gary Hartleben »

I have the motor running now and headed to the lake with my 1941 Thompson 14' TVT row boat. I spent the last winter scraping and sanding. I have 5 coats of varnish on the inside, and 2 coats primer oil paint with 3 coats of the finish oil paint on the bottom.

After about 5 min in the water the boat began to take on water around the transom area. More than normal leaking.

QUESTION: can I put system three epoxy over the paint? Is there a better way to keep the water out?

Thanks...
Phill Blank
Posts: 412
Joined: Thu Jan 05, 2006 4:20 pm
Location: Hurley, Wisconsin

Post by Phill Blank »

Gary,

Epoxy is not the right thing to use to seal a wood boat. It will not flex with the wood and will crack.
First determine where and why the transom area is leaking. Leaking can be caused by open seams between planks or the joint between planking and transom boards that where not caulked before painting. Also loose fasteners which are allowing a joint to open up enough to allow water to leak in. Bad wood with in the joint between hull members which is not visible when sanding can also be a cause.
Once you determine why the hull is leaking fix the cause do not just put a bandaid over it.
Any caulking used should be a flexible caulk design for wood boats. BoatLife is a good one that I have used with good results.

Good Luck,

Phill
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John Hart
Posts: 208
Joined: Sun Jan 29, 2006 7:26 pm

Post by John Hart »

Gary... I agree with Phil, that you should determine, or at least try to determine where the water is infiltrating... I did this on my Seacoaster, and did use a combination of caulk and epoxy to eliminate the symptom. I am not sure if your transom is painted or varnished.

In my case, I was getting about a cup of water that seeped in and collected around my drain plug, after the boat was in the water about an hour or so. I was surprised since I had a half dozen coats of varnish on the whole transom. However, I did not want ANY water at all to seep in. I had spent 600+ hours over several years redoing the 1960 boat, but had not removed and rebedded/caulked between the transom and garboards/planking. That may have been an oversite, but I had not even considered it. (See John P's posts of his Cruisers restoration... WOW.. if I had it to do over, I might have tried that, but I was inexperienced at the time)

Your situation may be way different, but here is what I did.

1) Used a bead of 3M adhesive sealant (black, very sticky, 4200 I believe) along the inside of the transom where it met the floor... and I masked above and below the seam on the outside, and tried to force sealant into the joint with a syringe and a putty knife... and wiped off the excess with denatured alcohol. Not much if anything went in, and I ended up with a line maybe as thick as a pencil lead or less.

2) I still got a little seepage, so I tilted up the bow to a bit of an angle, and brushed on and syringed in Clear Penatrating Epoxy sealer inside so it would run into any gaps not sealed tight by the inside caulking. (this will strip varnish so be aware and try to get it just where you want it)..

3) I still got a little water coming in... I wanted ZERO water seeping in. I was convinced it was this seam that was the location of the water coming in since I noticed that not much came in when the boat was going 30 mph and that seam was above water, and when I blew into the crack with my face tight against the transom, I could force air slowly through. I had some Smith's Laminating and Layup epoxy, which I have found to cure hard, but not brittle... it stays somewhat flexible. I put blue masking tape on the transom about 1/16 or 1/8 in next to the joint between the transom and planks ends (outside), up to the spray rails or so. then I put clear tape over the blue tape. Then I used an small brush to put a thick pass of L&L epoxy over the ends of the planks, including that 1/8 area bounded by the tape. I think I did several passes... After a few days, I brushed on three or four coats of varnish (maybe several hours apart) over the newly coated area.

This worked for me... As I said, I am a bit compulsive about keeping water out of the boat, to minimize any rot. I boated several hours last summer, and maybe two times this summer of a couple hours each.. I have checked repeatedly, and there has been ZERO evidence of any water coming in. ... Dry as dust.

My logic for choosing this approach includes the following.

1) I was not going to disassemble the boat and reassemb with new caulking

2) The only thing I had to buy was the caulk

3) It was fairly easy to execute

4) The L&L epoxy dries as clear and glossy as varnish, so while you can see a thicker coating over the seam, if you are not looking for it, you don't notice it

5) Nothing was done that prohibits future disassembly... the 4200 is less permanent than 5200... the CPES soaks in vs. Gluing things together like with a lot of 'hard' epoxies.

6) If I didn't like it, or when I revarnish the transom, the bead of L&L epoxy will sand easily.

So I saw no downside, and a potentially good upside...I had also bought Boatlife Lifeseal clear caulk and considered bounding the seam with tape and putting a band of caulk, but I choose the epoxy instead since I knew it was compatible under and over varnish, and would sand for future varnish applications. I figured a silicone caulk might gum up sandpaper and be harder to deal with.

I conclude that it was the right thing to do in my case, but may be way off for your situation... I just wanted to give you some options, so you can manage against the level of time you want to spend. If your transom is painted, you might just use clear caulk over the seam, if you think that is the main location of infiltration. I am also presuming that you are just facing a sealing and not a structure issue.

Good luck.

John.
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