Repair or Replace Teak Coamings?

[MHBsailor]

I like the rod idea that adamganz posted, but I'm wondering if the teak coaming is clamped between top and bottom while the epoxy sets up? Also, is penetrating epoxy applied to the crack before clamping?

In a related post to that link, another solution was to drill holes from the bottom of the teak coaming and then use wood screws instead of rods along with epoxy. That sounds real interesting too. I'm also thinking maybe drill holes at the ends of the cracks on the back side of the coaming (assuming the crack goes all the way through) but not all the way through the coaming so they won't show up at all on the cockpit side. Food for thought indeed!

What would be a good adhesive to remount the teak coamings once they are repaired?

[jbenagh]

Two things:
1) it's pretty stratightforward to drill a hole in a thin board like a coaming. Use a stick clamped to the face of the board, and then use a long bit, preferably with a helper. I've done a lot of these in the course of wooden boat building and it is way easier than it seems before you start. Practice on $5 of pine before you tuck into an expensive coaming.

2) If you do this, use bronze rod, not stainless. Stainless, although a little bit cheaper (maybe 20%), will eventually suffer from crevice corrosion in this application. And the poor person who has to fix this 10-20 years from now will be faced with drilling out a really hard stainless rod (an impossible project).

Jeff

[MHBsailor]

Thanks Jeff! I forgot to ask at the beginning how to remove the entire teak coaming which was presumably set in adhesive at the factory without damaging it (after removing any screws or bolts first lol). What modern bedding compound would be appropriate for rebedding the teak coaming upon reinstallation?

[robh]

Thanks Jeff! I forgot to ask at the beginning how to remove the entire teak coaming which was presumably set in adhesive at the factory without damaging it (after removing any screws or bolts first lol). What modern bedding compound would be appropriate for rebedding the teak coaming upon reinstallation?

You were asking Jeff, but my additional 2 cents!

I had to use a heat gun, a scraper, and a lot of elbow grease. Having a lot of small wooden shims to place under doesn't hurt. My combings were adhesived in place, with I assume 4200, since 5200 would have required a chisel more than a heat gun. I'd go with 3M 4200 or 4000, since it is strong but can actually be undone when required. I just started near the stern (easier to access and slowly scrape it off the fiberglass back there than towards the front of the cockpit) and worked my way forward.

[John Stone]

I’m a big fan of 3M 4000. But...if you are going to varnish the coamings then I’d go with a teak colored bedding compound like Boat-Life Life Caulk. You will tape the coamings, but no matter how good you think you are you will get some varnish under the tape and on the white caulk. It’s unsighly to me. A brown caulk keeps any errant varnish from contrasting. I used 4000 on my coamings and boat caulk teak colored caulk on the winch bases and there’s is no comparison. I posted a picture under a similar thread a year or two ago. If I can find the picture I’ll post it again.

[John Stone]

Here is a picture of the two different colors of bedding compound juxtaposed. Note that I used white 3M 4000 along the bottom edge of the coaming. Crisp white and it matches the gelcoat. But, several years later, and an additional 10 coats of varnish--'cause you have to keep varnishing those coamings--there is some varnish staining on the bedding compound. And, I am very careful about taping. Plus despite the fact the 3M4000 has a UV inhibitor it still turns kind of chalky.

But, note along the bottom of the winch bases and under the bare teak pads on top of the winch bases and between the winch bases and the coaming. I used teak colored Boat-Caulk. You really can't see any caulk. It blends in. Imagine what the white caulk line would look like between the teak joinery. The teak colored caulk looks just as good today.

So, choose wisely. When I someday remove and recaulk the coamings, I'll use a teak colored caulk.

[jbenagh]

I can't add much except that I like Sika Flex 291 for this. It holds up well but can be undone. Even 3M 4200 grips too much for anything that needs to come undone. And coamings are not all that critical on leaks.
Thanks for the kind words.
Jeff

[MHBsailor]

Outstanding John - Looks better than new! Great observation about the teak-colored BoatLife caulk too. Thanks so much everyone for your contributions. I feel much more confident about tackling this repair now. JD

[adamganz]

[quote="NarragansettSailor"]I like the rod idea that adamganz posted, but I'm wondering if the teak coaming is clamped between top and bottom while the epoxy sets up? Also, is penetrating epoxy applied to the crack before clamping?

In a related post to that link, another solution was to drill holes from the bottom of the teak coaming and then use wood screws instead of rods along with epoxy. That sounds real interesting too.

Hey there, NarragansettSailor: I did all of my drilling/epoxying, etc with the coamings in place. I clamped the boards, inserted epoxy in the crack with a syringe. My coamings are in rough shape so I didn't feel that they would survive removal. That said, the crack on mine was toward the bottom of the coaming, like yours, so if you are able to remove the boards, I think drilling from the bottom would work even better.

[John Stone]

You are much better off removing the coaming. Doesn't mean it has to be removed just that it will permit a more thorough professional result.

Re penetrating epoxy. I have talked with the tech branch at West Systems regarding the claims for penetrating epoxy. They say it's a fallacy...it's not how epoxy works. They have run tests that penetrating epoxy is much weaker than unthinned epoxy. They state the best way to thin epoxy is gently warm it before mixing it. It will kick faster however. Also, warming the substrate then turning off the heat and allowing it to cool as the epoxy flows in will draw the epoxy a little further into the wood cells.

But, they also told me you can thin epoxy with up to 5 percent acetone. I have done that on occasion for sealing plywood endgrain though I don't think it really changes the results much.

If you go to the West Systems website they have links to the performance data on penetrating epoxy.

[jen1722terry]

I've used denatured alcohol to thin epoxy for decades. Not sure if this is recommended (I never asked), but all the joints seemed to hold up. Handy, as we have it on board for the galley stove.

Good for cleanup also and not as nasty as some of the other solvents.

Cheers!

Terry