Epoxy sanding question

Im using RR on a 6’0" thruster.  Ive recently started to use this stuff. I really like it but Im hearing things like I should let the board cure in heat for a couple days after I hotcoat?

Apparently it is supposed to help in the sanding process. I really dont know, although I want to believe it because sanding this stuff is a b*tch. Not like the poly’s I used to do.

Can anybody shed some light on this, and possibly critique me a little?

I hard sand with 50, taking down the laps, finbox, leashcup etc (3" small soft pad)

Then I quickly hit the deck, bottom and in between fin slots with 50 (same pad)

Then 80 grit

Then wet sand with 220, 320, 400, 600, 800

The board does come out good, although Im not a pro so I have some wheel marks and lam gouges every now and then but nothing too major.

But I really feel like its too much on account of searching on some forums on here to see what other have to say.


I too have found epoxy a lot more labour intensive than poly, poly sands easily without clogging paper whereas epoxy dulls and clogs paper pretty quickly regardless of cure time. I have washed and cleaned prior to sanding and used slower speeds etc., still a lot more work. Mind you I started with 120 as the hot coat was pretty flat to start with, I think I’ll try with 60/80 to give it a quick rough up and remove shinies then go down the grades. there’s got to be a knack to this :slight_smile:

I’ve also got some 60 & 80 grit wet and dry I want to try but I’ll have to do this by hand.

The last board I blocked down by hand and it seemed relatively easier than machine in that the paper lasted a bit longer and didn’t clog as much but the finished product was nice and flat and didn’t take that much time really. Would still rather get the machine sanding thing down though :slight_smile:

Does anyone have any recommendations for sand paper type for epoxy?
I think a combination of the right paper and machine speed will be key, I’d love an 8" air powered DA to use wet and dry but that would require an industrial sized compressor.

might wanna peruse the archives on that one...


Low speed, and keep moving.  Epoxy softens and turns to rubber when heated.  I use a router to take down the fin plugs, then just lightly sand the last bit.  Never as course as 50 grit.  I also use a file to take down laps.  Get one at a body shop.

Epoxy must be mixed perfectly, and well cured to sand well.  I post cure by sitting the board in the car in the  sun for an hour.  But I use Poly blanks,  Dangerous to heat an EPS board.

There are some quick hints

use a bigger sanding pad

3 inch,,,,,, realy?

80 ,,120,,,220,,,,320 for the sand coat,,,why are you wet sanding below 400?

if glossing stop at 120 and shoot gloss unless your spraying then sand finer

read the archives

Completly cure epoxy is hard and don’t clog paper. Scrubb with water and scotchbrit before sand if there is blush (like oil on surface). Roto-orbital with slow roto and fast orbital are the more effective sanders, but expensive. Only orbital with big orbite (8 or 10mm) are good too, way better than roto only.

The way i do it:

lam, then when lam is set but still tacky, fillcoat with a smooth sqeegge then hard brush. Let completly cure, i have an oven to speed it, then sand flat with my orbital with 60 grit (very fast to do if good shape and tight lam, 20/30 min for a 7 egg), then finish coat with PE or hot epoxy. PE it’s easier to finish but lightly crack when ding, not a big problem.

Sorry for my franglish