Yes…diluted spackle, so it spreads and strikes off more readily with a squeege. Straight from the bucket and its an irregular patchy over build requiring excessive sanding or risk of delam especially if heavily painted. Although some contend tons a paint is just fine.


Rick, Before doing my first EPS / Epoxy board recently, I did a test on one of the cut-offs from the blank. I prepared four different sections. All were then glassed with one layer of 4 oz. fabric and RR epoxy (fast hardener). I then did my best to destroy each section to see what was the weakest and what was the strongest.


  1. EPS only. Sanded smooth. No spackle.

  2. Sanded smooth, no spackle, painted with water-based acrylic.

  3. Sanded smooth, spackle only, no paint.

  4. Sanded smooth, spackle, painted with water-based acrylic.


  1. Resin soaked in the most, fabric was the driest. Tear off of the glassed-on fabric was mildly difficult.

  2. Resin soak was moderate. More resin stayed in the fabric. Tear off of glass was harder than #1.

  3. Resin soak was minimal. More resin stayed in fabric. Tear off of glass was more difficult than #1 or #2.

  4. Resin soak was minimal. " " " " " . Tear of was hardest of all. The fabric ripped when pulled with enough force.

My conclusions are that the bond to the EPS is not so important since eps is so weak. When more resin stays on top, it creates a strong shell of epoxy resin and fabric. The bond to the spackle itself was good, since when the shell did peel off the spackle stayed stuck to the resin, and the eps broke off.

I think the spackle works good. My recent board had lots of clear resin areas, and the spackle made everything look nice and white.


So wouldn’t it be better to paint over the spackle with waterbased acrylic???

Even if you only paint it white???


I agree with all of the above, except the cosmetics… which you can get with epoxy/ballons if you do more than one coat (the second a bit thicker than the first) and add some white pigment.

The only thing I can say that slurry is better than spackle is that it increases durability, even if it’s only a little bit. Still, it’s worth it to me for my own boards.

MDS, In the test I did, the difference between the spackle only, and the spackle with paint was just a slight difference when it came to destroying the lamination.

Incidentally, I also took a hammer and gave each test area a good pop. The softest was the no spackle area. The hardest, once again, were the spackle only area, and the spackle with paint area.

One thing that hasn’t been discussed is this: The spackle is porous, and it absorbs resin. Even though the EPS is sealed from deep penetration of resin, the spackle has some resin in it. So there is a little thickening of the resin layer beyond the fabric thickness.

I still think the main point has to be: EPS is weak. Bonding to the EPS is not the main issue since the bond is only as strong as the weakest component. My conclusion is that creating a strong shell is the most important part of making an EPS / Epoxy board. Think of a hollow carbon fiber board. No bond at all, but a strong board.

I would love to hear from anyone else who has knowledge and/or experience in this area.


I get the best results when the mix is thinner than mayo if the epoxy is at room temperature. It should flow in the tray. The ratio should be about 1:1, epoxy/hardener mix : balloons. If anything, a bit more epoxy. And I use a nice, wide spreader.

If you do it right, there will be no beads of slurry from the edges of the spreader, and you only need to TOUCH it with 100 grit. I basically wipe the board with the sandpaper.

Protect yourself with a good mask. The balloons are nasty.

One of the problems I always had with epoxy/micro was the bond between that layer and the laminate. You can’t really go after a seal with a sander … just doesn’t work. You can’t use Additive F in the seal to eliminate the blush because you can’t airbrush onto a coat of epoxy with additive F because the paint beads. If the seal has significant enough blush to give you problems with recoating then your f#%ked. This problem doesn’t come up often but make boards long enough and it will. Spackle has no blush issues and the resin does soak into it making a better bond to the foam than anyone believes. Also, the exterior spackle is waterproof just like exterior water based paints are. Water the stuff down so that you get a nice thin coat and it doesn’t delaminate, not even with water intrusion. I also don’t have to worry about breathing microballoons or worse cab-o-sil.


Classic quote. Exactly, it’s not like Greg l has done any EPS Epoxy boards before. Maybe the problem is that people aren’t getting there Dap Fast n Final to the proper consistency?..It has to be mayonaise…Not honey, mustard, catsup, creamy peanut butter, Grey Poupon, motor oil, tabasco, Jergens skin lotion, Nacho Cheese sauce, Poi, or even Apple Sauce.

Greg said “Mayonaise”.

I don’t buy or eat mayonnaise. Have nothing to compare it to, what am I going to do?

Only works if mixed to a poi state in HI.

ACE … baby poop … perfect consistancy!

I’m going out on a limb here, but i don’t think ACE eats or buys baby poop either =)

And yes, of course,… Baby Poop!

But not to be mistaken with baby vomit, or dog poop. Or even cream of cow shit.

I just laughed so hard my face hurts!

Too much!

…freakin’ spackle threads…

Hey Greg

It seem that you get a better surface to do airbrushing/pinlines etc with spackle rather than epoxy/micro mix.

“Spackle has no blush issues and the resin does soak into it making a better bond to the foam than anyone believes”

Will the epoxy still soak into the spackle and bond properly if you have painted onto it??

With poly boards, I do pinlines and complicated art work on the sanded hot coat, then seal with a sanded gloss coat.

But you have to be careful not to sand into your artwork.

If I were to do my artwork onto the spackle, then lam over the art it would make things a lot easier.

Just worried about the bond of the lam to the spackle with paint on it.

The tests mentioned earlier suggests that it was the strongest combination, but I just want to be sure before I go ahead and spend hours on some artwork only to have problems later on.


Aloha Bammbamm:

I spackle sealed the 12 ft. SUP like you instructed me when I saw you at Fiberglass Hawaii. I was really surprised how light the board came out. I am using DAP fast and final on all my EPS boards from now one. Thanks for that great tip!


MDS, I did some rail painting on EPS after spackle. The only glitch I had was in some areas the spackle had been sanded through to expose some of the foam. Those areas had a texture in the paint. I was worried about it until I layed down the laminate. It all seemed to even out, and looked fine by the time I got to glossing it. I don’t know how it would look if you did some intricate work though.

Try an experiment on one of your cut-offs. Sure saves headaches later.

Like I wrote before, when I did some combinations of spackle and paint the bond to paint worked fine. I would recommend flat paint, not glossy.


Detailed art work and spackle is a no go. The same attributes that make spackle the wonder seal of the 20th century, are the demise and scrounge of it’s under doing. Spackle lets Epoxy soak in right?..Epoxy is prety thick right? Well just think how well paint will soak in. So if you laying down a super thin india ink pin, or doing panel and shooting between the tape, your going to get more and excessive bleed.

Ever wonder why most EPS boards are clear or have minimum art work? Or if they are colored it’s usually the whole board, and it’s done in a light color?

But that’s not to say that painting on the sanded hot coat is a bad chioce.

…do your art on rice paper and lay it under the cloth…you can get as intricate as you like and you’ll never sand through to it…

Is it OK to use house brand light weight spackle, the off brand stuff carried at Home Depot? or best to use the name brands mentioned here? And what exactly is the acrylic paint that always gets mentioned here? is it acrylic latex house paint? an exact brand name and product would be helpful to figure this one out, thanks.

That’s always been a great option. If you do the art mirrored you can then put down the paper paint side down which gives even a bit more sanding room.

I’ve used all kinds of spakle and they all worked but Dap Fast and Final has always been the best.