Hi all,
I’m planning on doing a fabric inlay on the bottom of an EPS blank. Do you guys still seal the blank or not bother? Thanks for all the great advice! Cheers.
Seal it first !
Thanks Bill! Was 99% certain this was the case but good to confirm! Happy surfing 
I use spackle on light EPS. I have been using the DAP Fast n Final, but I don’t recommend it now. The formula was changed and it is not goo for surfboards now. It would be OK if you plan to cover up the lamination with paint, and it would be OK if you will do a fabric inlay covering it. The main problem is that is not white. It also seems rubbery in texture when you sand it versus a powdery texture. It could be that I didn’t let it dry 100%. I usually cover up my foam with pigments or paint them after laminations, so it gets hidden.
I get the spackle really thin then work it into the foam with a squeegee. Try to keep the layer as thin as possible, and lightly sand down till you can just see the foam beads. You just want to fill voids and make the surface smooth. You want have the foam exposed for a good mechanical bond.
I found that using epoxy resin with filler requires really good technique because sanding it later is a pain. The resin dries very hard, and sand throughs will be bad.
Good surfboard EPS doesn’t need spackle because the beads are really tight. You can get a clean, really smooth surface with good EPS.
With faster époxy in hot climate you can lam all eps without seal. À pré seal help to have a clean bubble free lam easily. If spackle work fine and is use by many, for me micro slurry give an harder coat better for cut laps, be carreful to scrap it well so there is only minimal sanding, juste to scuff the surface.