Hello FWW readers,
Question on finishing a tabletop for a powerboat.
They say that when finishing a table top, it’s a good idea to put as many coats of finish on the top as on the bottom to keep a balanced moisture absorption/release.
I’m wondering if this applies to a marine table application. In this case, I’m using Total Boat Gleam II, 6 coats on the top, 2 on the bottom. Do I need to continue with the 4 additional coats on the bottom?
Any advice/guidance is gratefully accepted.
Cheers,
Erick
Replies
I'm not familiar with the products you're calling out, but pretty much all environments have moisture swings large enough to make wood move. For an average table I'd call it done where you are now.
You might find folks well versed to using your finish at:
http://forum.woodenboat.com/
You need a few coats on the bottom and as many as you want on the top. Written from my varnished cockpit table.
Are you STILL trapped off the coast? Big storm just hit here in NYC and headed North!
The storm will probably make a sharp turn East just enough to miss our area . In any case we are in a Safe Harbour (literally) and I am doing touch up on the outdoor teak trim after an active sailing season.
Sad that the season is over so early. Have fun on the brightwork!
Erick,
When I did a Furniture Finishing course in technical college (in Australia) we were taught to do the same number of coats on both top and bottom of table tops, and we weren't talking about a marine environment where the humidity would be much higher than on land. I'd do the same number top and bottom.
Cheers,
Ian.
Hi Ian,
My gut feel was to do as you say. Thanks for confirming.
Cheers,
Erick
I think the advice to apply as many coats of finish on the underside as on the top isn’t talking about high-solids sealing finishes, but rather, thin finishes that don’t easily seal all moisture out with just a couple of coats. Personally, I would say you’re done, or at the most one more coat on the underside. Both top and bottom should be sealed by the 2nd coat, or at most by a 3rd coat. My 1 1/2 cents.
Any of you has maintained varnished teak or mahogany on a boat ?
Me, for years, on my sailboat. Mahogany companionway and cabin table & trim. Teak grab rails on cabin top and stern trim. Not sure how relevant though. The reason a spar varnish like the one the OP used requires 4-6 coats has little to do with sealing and everything to do with UV resistance. The product says each coat will be 1-2 mils thick when dry, a large range of final thickness, hence the 4-6 coats, to be sure there’s enough UV resistance, and the underside doesn’t need any UV resistance.
Exactly, the top is exposed to abrasion and sunlight while the underside is not. I stripped and refinished this 1978 solid teak table 20 years ago and added a few coats since. When adding coats I mask the contour so the underside does not get brush marks or drips. It has over 10 coats by now but only the first few diluted coats on the underside.
Yes. It's not sealing the wood from moisture that makes the difference, it's the oxidation of the wood from UV light that causes film finish failure. The best marine finishes have the best UV blocking, where cheaper "marine" finishes do not.
Paint works really well in large part because it blocks UV the best.
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