MAS epoxy 2nd coat

Builder's Forum
1

I have read several different things about when to apply the second coat of MAS epoxy. An article on the CLC website says it can be done up to 30 hours after the first coat. I added the first coat about 24 hours ago. The epoxy still feels a little tacky. I did a “cotton ball test” (although I use a Q-tip) yesterday and it failed. Should I add the 2nd coat in the next few hours or wait until it is no longer tacky?

2

If in doubt, a light sanding will sort it out.

3

Jon,

Should I just go ahead and sand? I just check and it is now tack free.

Rob

4

If its tack free you are ready to go. For me, the sanding is only to address knocking down runs or drips or other edges like along the edge of the tape.

5

Howard,

I can coat without sanding even if I am over the apparent 30 hour limit?

Rob

6

I probably would sand if I had any doubt that one coat would adhere to another. But I’m no expert, just another builder.

7

Jon,

I think that would be a good idea. No big deal.

Thanks.

Rob

1 Like
8

you can use sandpaper to knock down drips, runs, and edges. scotch brite pad to scuff up the rest if you want. 30 hours is not a ‘hard’ number especially for an overcoat on a plywood panel…where the first coat is inevitably rough by nature if you only put a thin coat down.

you just don’t want to sand you first coat off…its very thin to start.

howard

9

Howard,

Thanks. I lightly sanded and added the 2nd coat this morning before it got too hot. I did sand down (or at least smooth down) a large drip but It is just the bow section. I am getting a little less perfectionist as I progress. I’ll save that for the exterior.

Cheers,

Rob