So Im starting to notice on all my EPS boards that there is major separation between the glass and the foam. They look like big fat air bubbles, its god aweful.
I seal the foam with DAP fast and final spackle which was recommended to me to use. Then to sand it down with 220. Im assuming the reason why the glass is separating is because of the spackle? Obviously its not strong and could act as a bad buffer between the cloth and foam.
Has this happened to anyone before? Really need help on how to prevent this. Maybe its my sealing techniques or what Im using? Thanks guys.
Has anyone here used PU moisture cure? That's the pourable one… not the white one out of a caulking gun.
On a modeling project we did this. We made the PU brushable by diluting with Acetone 10% all with the concent of the manufacturer of the product. Worked like a charm but then agian we did not intend to cover it in resin. However I have little doubt epoxy would bind to it nicely, although the colour might be an issue as the PU glue looks the colour of Poo. That's what we call it … POO Glue. LOL. But seriously this shit you can paint… Now the paint? hmmm another issue entirely. I just wish I had more time to experimentate!
What density foam and glassing schedule? Is it happening deckside / bottomside / both?
Stringered or stringerless?
Where are you?
What kind of temps and treatment are the boards seeing?
For what it's worth, I have a stringerless fish (2-lb EPS with fully lapped 6/4 top and bottom + deck patch) I sealed with the same spackle. As an experiment, I have left the board in the back of my pickup truck (with a cover) for like the last year here in Florida. I figured I would try to mimic the worst abuse someone could throw at a board, should I make them one. So far, near as I can tell, nothing. I'll bust out some soapy water one of these days and see if it's blowing air around a fin box or something, but I haven't experienced the dreaded delam.
That said, I can not disagree with the logic of sealing with epoxy slurry.
I've spackled a few boards… Can't say I've seen a difference. I just make sure I mix up plenty of epoxy and and lay it up wet so the EPS can soak it up.
I've done 10,000. No problems but like Barry said, put it on thin and sand most of it off. You just want to fill the spaces between the beads. 220 sand is also overkill. Your reducing the bond by not allowing the resin to key into the surface.
Thanks for all the input. My temperature is 75-78 pretty consistently with my heaters.
I took into consideration of applying a very thin coat just to pour over the beads. It makes sense for that considering the spackle can act a weak buffer between foam and glass. I will try to get some pictures tonight. I'll also try upping the paper to 320 or 400.
PS to Greg, I want to wipe my board with asetone to clean the deck and bottom before applying a pinline. I use your resin for the glassjob. Is this a nono? Considering I know epoxy doesn't go well with asetone. Is there a difference if its cured?
he said "sanding to 220 is overkill" so, sanding to 320 or 400 is ridiculous overkill. you need to go the other way with the numbers. 100 is good IMHO.
Also, you are letting the boards completely dry before you glass right? I let my boards dry for a minimum of 3 days inside the house after spackle and before glassing.
100 is what I always used. 100 screen on a soft pad to be exact. I always let mine dry overnight and never had any issues. I would use denatured alcohol to clean where the pins are going. With acetone if you have just a little pin hole you could be looking at a big problem. Denatured won't hurt EPS.
