EPS surface smoothness and rails

Hi All,

I’m a big fan of this forum and read plenty of threads… Now, I need your advice. This is my first self-made board. I built it from EPS 30 (i think this is the #3 EPS) and did cut it out with a hot-wire cutter. So far everything went astonishingly well. However, next Wednesday I will get the the fcs fusion plugs and I wanted to make everything ready until then. As soon as I have them, I’d like to glass. My question is now, how far should I go with sanding the EPS? I’ve read a lot of different stories about how rough or smooth it should be as some stated to bond with the epoxy will be better if the surface is more rough. I first sanded with,40,60,80 and now 120. I posted a picture and I’m asking for your advices, if I should proceed with sanding untill 240 or not. 

The second question I have is about the rails. This board should be for small waves. Its size is 5’3 x 23 x 3. I am 5’4 and about 145lbs. I want to be able to make some turns (sanding the rails down more), but I’m afraid to take to much off. Any suggestions?

first and second images show regions sanded with 120. The rails are sanded with 120 too, but they look more rough.

the other images are showing the rails…

Thank you very much in advance!

Regards from Switzerland


I wish I could help you out, but I think 220 is what a friend uses on final touches. Anyone? I think he uses red devil brand light weight spackling w water to squeegee it on? Then fine sand w 220?

I am not sure if it is of any help, because i made only three boards up to now , all were eps.

I dont think it is necessary to sand finer than the 120 grit, an the spackling i did didnt bring much effort.

All the best




I finish mine to 220.

If done cleanly with no rips,

Spackle is not nessesary.

If you must spackle,

add  acrylic not water.

The acrylic serves as a binder.

Makes it stick.

Sand out with a soft block and some sanding screen.

Sand most of it off.

Back to bare foam.

Leaving only the holes and voids full.