how to sand epoxy surfboards

General Discussion
1

To get a board sanded good enough, it just takes me ages!

Going slowly with my Festool Orbital fine sander

To get it real fine without scratches, i start with 100 grit

Keep the sander flat best i can

Then go up 150, 180, 220, 320, 400 and it does look very nice, feels nice too

Costs me a lot in paper, about 12 bucks worth of paper, but if guys who don't surf say the board is well finished, i am happy for sure.

Start sanding the highs, let it slip to the low parts, middle towards rails.

Rails i try and sand only with the papers from 220 up and a super soft pad, or i will see fibreglass, and i don't want to see that no more!

Padwise... i try and skip the hardest ones, they bite into concaves and vees

I only sanded epoxy ones, so i don't know about poly [thank god?]

Epoxy can get a bit hot and deform if you stay in one place, so you need to move around

So how about your style, what machine or machines do you use? And what do i do wrong?

Woopsy from  Holland


2

well, for one thing, don’t use an orbital sander. I just doesn’t remove material fast enough. I’ve tried it and now I just wait for days when I can go outside and spin up my big one and let the dust blow to the neighbor’s yard. You may not be able to do that where you live.

Of course removing material faster means never taking your eye off the ball.

Good luck Wouter.

3

I don’t agree with you greg. I have and test many kind of sander, and after a bit more of 100 epoxy lam, for me orbital sander is the go for epoxy. At least a powerfull orbital with big orbite (5mm mini) or the top: roto orbital. I do my fill coat on tacky lam then let fully cure before sand “flat” with my orbital, hard pad with 60 grit, no more than 10 min for an 7’ egg botom, i sand a shortboard in less than 45 min now (rails by hand). Finish coat with poly iso and sand with orbital, soft pad, 180 and 240 grit the 320 scoth brit pad. That give a decent speed finish as good as many surfshop production boards, and more durable than lacquer.

Sorry for my frenglish

4

Lemat, maybe it is just my poor orbital sander.  Would you put up a picture of the one you recommend?  that would really solve some problems for me.  thx

5

Greg

try a festool Rotex Orbital sander

720 watts

rotary 330-660 rpm

orbital 3300-6200 rpm

dust extraction

switch between roatary and orbital 

change pads without tools,just clicks

very very slight chance of burn throughs, as it does not get hot with all the air moving through, and the dust being extracted

type is rotex 150 fe [q]

6

Well, it says right there on their website http://www.festoolusa.com/products/rotex-sanders/ on the non-orbital sander: “Pure rotary sanding action provides the most aggressive material removal”.Although rotation + orbital is better than plain orbital, It’s hard to beat the sanding speed of a large disc on a 2800RPM grinder.

7

Orbital mouvement give a lower relative speed of grain but a better cover of grain on surface .You can use a coarser grit that sand quickly and reduce/avoid surface temperature increase. Finally, for epoxy, a faster an effective flatter sanding with lower paper use. All pro composit boat builder i see use those sanders, and they sand a lot more than surfboards.

Greg this one is good too and lower price than Festool:

Bosch 150gex

I use this AEG too, low price, not as efficient but still correct with big orbit for epoxy and small for poly finish.

8

My brother has the festool sander, had it for at least 4 years now. I’ve used it a lot and the rotary mode will cut faster than the orbital mode. No comparison between how much more it cuts when in rotary mode.

 

9

80 grit then poly finish coat straight to 320 or 280 and your done