FCS plug on PU/epoxy

I’m going to try the PU/epoxy combo in the next days. I usually go with the FCS plugs (X-2). I plan to go the way i’m used to with poly: once the hot coat is done i plug the board. The board being glassed with epoxy i could do it with epoxy but don’t want to get any problem with exotherm, so i’m going to use poly resin+ “FCS powder”+ white pigment. Any advice?



If you have epoxy left, you can fill it bit by bit and use the freezer technique (so you don’t have to buy extra resin).

I would advice to mix everything first in one cup and then fill several small cups you put in the freezer and then fill it cup by cup (so you don’t have to re-freeze the resin).

I don’t know how exotherm your resin is so maybe a test could appropriate. But it should work because polyurethane is a thermosetter and will not melt.

Use epoxy. No worries with exotherm and PU, as it won’t melt like EPS. You can use wet rags under the plugs to absorb any unwanted heat, but I do it all the time and never have any problems. If you use PE, you might have an issue with the resin around the plug bonding well to the lamination, which it HAS TO DO to ensure the best possible install. There’s a lot of force on the plug… maybe enough to cause failure between the plug resin and the lam/hotcoat. Then you get leaks.

Hi NJ Surfer,

PU or EPS, you still need to worry.  I learned the hard way about setting plugs and exotherm.  EPS melting is one problem.  Epoxy boiling and bubbling is the second worry.

Even in PU, I do a three step application.  First, without the plug in place, fill the H pattern, cover the foam, but below the plug.  Second to half way up the plug.  Third to the top.

Fusion are faster, but I like a direct connection to the deck.

Boiling epoxy sounds like a disaster! Fortunately, I’ve never had that happen to me with a plug install. Better safe than sorry, though… Wet rags have always done the trick for me with PU foam, and always at least a two stage pour for EPS.

Mmmmh, thanks for the tips but i’m not convinced with the epoxy formula! If i use poly there is no problem, sure! The main question is the quality of the bond with epoxy. I think it’s not a problem with the “H pattern”, good mecanical bond with the deck layer once “the round scratch” is done. Not sure about the bond on the bottom. What do you think?