Builders' Forum Archives
Re: one coat & outgassing
Posted by LeeG on Feb 11, 2008
Don't worry about it.
It's mostly a maintenance issue for people who leave their kayaks outside in the sun for a long time and forget to leave the hatches off while there's moisture on the inside.
I saw a friends Chesapeake 17 age in one year age about what CLCs demo boats did in four years primarily because his boat was outside all the time with closed hatches. He made his in a class with one sealing coat. On the side panels and deck the wood was a bit darker than the cockpit side.
Sitting outside in the sun with closed hatches any moisture in closed compartments will eventually steam through micropores into the wood and darken the wood with tiny black streaks. It's a cosmetic thing, not indicative of any kind of damage. You would hardly notice it except for the fact that the cockpit isn't closed and the compartments are so the compartment side is slightly darker than the cockpit side.
I had it happen to my first s&g a CLC Patuxent where there were no hatches or bulkheads but the underside of the aft deck was glassed for 16" behind the cockpit effectively making three sealing coats next to one. After a couple years the glass section behind the cockpit was lighter than the section further aft that just had one sealing coat. It wouldn't have been noticable if the slight darkening continued to the coaming.
On another kayak the "black ick" developed even though it had three thin fill coats on the underside of the deck. On this one it was from the kayak being stored with wet float bags inside the kayak throughout the summer. With hot humid 95 degree days and water trapped between the vinyl bag and epoxied wood the stains showed up through the wood. If I had pulled the float bags out after every use before putting it on the rack it wouldn't have happened.
The deck can go on with partially cured epoxy, it doesn't have to be wet. I would roll/brush or squeegee on two thin coats, one after the first was tack free. I think the old manuals said you had to put the deck on while it was wet or it woudn't go on. I never had a problem. On one I even glassed on 4oz glass on the underside and put it on while the epoxy was soft.
For sealing/laminating plywood it's better to apply epoxy in steady temps or slightly falling temps. Slightly falling because if it falls too much curing slows down a lot with slow cure then when you heat the room back up while the epoxy is still sticky it'll outgass like Toms boat.
I discovered this on one little wire hole at the chines that didn't quite get filled with epoxy. Last two fill coats were in the mornings and even though the entire hull had four cured coats there was this little 1mm bubble of epoxy showing up on the hole.
The short answer,,don't worry about it, two thin sealing coats is better than one thick one.
In Response to: Re: one coat & outgassing by Randy R. on Feb 10, 2008
- Re: one coat & outgassing by LeeG on Feb 11, 2008