Questions about shaping, spackling, and coloring 1.5 lb (or lighter) foam...

[magentawave]

This video shows how to seal EPS foam with Solarez Zerovoc UV cure epoxy resin mixed with 25% microballoons. You'll see that the Solarez is really flexible after curing and makes the foam a lot more resistant to dents. It costs about $22 per pint or $33 per liter. I'm thinking that unlike regular epoxy, which takes a long time to cure, not much resin would get absorbed into the foam because it cures in 3 minutes.

Here is a comment at Amazon about it in response to a bad review from a misinformed user:

"The primary purpose of this formulation is to coat raw styrofoam with a durable, non-yellowing, flexible coating so that a FINISH resin can be applied over it. i.e. ZEROVOC is not a finishing resin. Some people choose to use Spackle over raw styrofoam and although this works, it does take a good 24 hours to cure dry and when it does, it has about the same tensile strength as Parmesan cheese. In assessing the strength of a composite, it is only as strong as its weakest link. ZERVOC's strengths are as follows:
1) it does cure quickly, like in 3 minutes yet with a slightly tacky surface which in turn is designed to be hot-coated. If you were to judge a laminating polyester with the same scrutiny, Silmar 249a would have never have made it off the ground - it is a LAMINATING RESIN and it is designed to be tacky when cured.
2) ZEROVOC provides compatibility to an EPS (styrofoam) lamination. The modulus of styrofoam is very dissimilar to that of a hard-shell finish polyester or epoxy. When EPS boards are laminated directly to rigid finishes, something has to give when the board flexes (unless you want a perfectly rigid board which is like surfing a board with rigor mortis). ZEROVOC "compatibilizes" the EPS to the exterior finish so that you will get flex in your EPS board without delaminating it.
If you write a negative review of a product, you should really know what you are talking about because it is very similar to pointlessly defacing property. I have worked for 28 years developing products to aid surfers. View the videos FIRST and understand HOW to use the product and view the positive results by surfing professionals before making an elementary review.
Thank you."


Have you used this to seal EPS?

[wildman]

Tried everything. Shaping any EPS is super easy. Just need the right tools. Never ever ever use spackle. It always turns to mush and delaminates!!! Squeegee on the same epoxy you use for laminating to seal the board.
 

[magentawave]

Do you mix microballoons with the epoxy? How much epoxy do you think would be needed to "spackle" a board thats about 7'-6" long?

Tried everything. Shaping any EPS is super easy. Just need the right tools. Never ever ever use spackle. It always turns to mush and delaminates!!! Squeegee on the same epoxy you use for laminating to seal the board.

[55NSup]

I just sealed a 10-6 blank of 1 lb. Eps . I used 350 grams of epoxy and unknown amount of micro balloons.  Enough balloons to make mayonnaise thickness.  Not all of it ends up on blank, probably 80% of it. Squeegie it on with medium pressure.  Don't leave any on except to fill the little voids. Sanding only to take off any small excess bits.the blank is significantly harder than when I used the latex spackel last time.

[supuk]

What I found was that when using epoxy micro mix that it needed to be sanded very well before laying the glass as the microwave little hard bumps stopped the cloth from laying on the foam a left little air voids. Vacuum bagging would probably solve this as sanding it back is very hard without damaging the blank

[PonoBill]

ZeroVOC is a nice product, though kind of overkill if you're using epoxy. I haven't done any polyester/vinylester glass work for about 15 years. For a board the size of a sup I think you'd be adding a few pounds for not much gain. We really don't depend on styrofoam for much more than holding the layers apart. If it does cut down on pressure dings then it might be worthwhile to replace one layer of glass, but you'd need to experiment a buch to see where you came out. If i was doing production stuff then that might be worthwhile, but Spackle is easy and I know it works.

[magentawave]

And how much weight is added or not when sealing with epoxy/microballoons verses spackle has been the question I've been trying to get an answer to. Since the epoxy/microballoon mixture is put on super thin and then mostly sanded off, how could it add a "few pounds" to the board? What am I missing here guys? 

ZeroVOC is a nice product, though kind of overkill if you're using epoxy. I haven't done any polyester/vinylester glass work for about 15 years. For a board the size of a sup I think you'd be adding a few pounds for not much gain. We really don't depend on styrofoam for much more than holding the layers apart. If it does cut down on pressure dings then it might be worthwhile to replace one layer of glass, but you'd need to experiment a buch to see where you came out. If i was doing production stuff then that might be worthwhile, but Spackle is easy and I know it works.

[wildman]

Never use dry wall spackle. It always delaminates! Only use epoxy to "cheater coat" the foam. Then scuff the surface and laminate. Epoxy will never delaminate!

[surfcowboy]

Great thread over on Swaylocks with Greg Loehr. He still says spackle after a lot of years and a lot of boards but I agree that it does seem/feel like epoxy would be less likely to delam. But then again, why wouldn't the epoxy just pull up from the foam, which is the weak part of the bond? But maybe that epoxy is making the skin more stiff which would help too.

I'd assume that the new eps, vents and epoxies are less likely to delam and that a lot of the fear around spackle is based on "the old days" of eps and epoxy.

Wildman, just curious, when were those delams? How long since you did one with spackle or saw a board delam from it? Also, was that 1lb foam or heavier? I'm not disputing what you say, just wondering if things have changed recently.

I might have to do some dark test panels when I do my next project and leave them in the sun.

[Biggreen]

There are MANY who've built more boards than myself, but I've only ever used spackle and never had a single delam. Course I do vacuum bag also, which I would imagine helps.  Each to his or her own, but spackle has always worked for me. That said, I just recently purchased some UV resin and UV eps sealer, so soon I'll be using a microballoon slurry to seal my blank. Just wanted to give the stuff a try. Curious to see how it works out.

[Dwight (DW)]

Keep in mind when reading Gregs comments on Swayloks he's talking about prone boards. SUP is still new by comparison. Experience based on SUPs only is tiny by comparison.

There are SUP guys who swear spackle increases risk, due to some bad experiences.

I never had problem, but I don't spackle anymore either.

I know a big time SUP shaper who won't even paint a blank due to some past delam. He only does resin stains now.

The rules are different with huge volumes of foam.

[magentawave]

And what about you, DW...  do you paint the blank or do you spray the glassed board with LP?

I know a big time SUP shaper who won't even paint a blank due to some past delam. He only does resin stains now.

The rules are different with huge volumes of foam.

[Dwight (DW)]

I tint my resin

[supuk]

Just thought I would do a test although I kinda new the answer but here is the result. I dried a pice of spakel for 48hours and then put it a glass of water for another 48hours and even now the spakel is still quite brittle and does not spear to be effected by the water atall. I have a few other tests I am going to try to try and get a bit more I depth info on what's realy happening with the various ways of sealing blanks.

[surfcowboy]

Excellent UK, keep us posted. I'd love to do some peel tests myself.

DW, I hadn't considered the extra foam and therefore more potential for gassing.