Using Spackle on a Clark Blank and Poly Resin

Aloha, I looked in the arcives … There’s some scratches/grooves on the Blank that were a little too deep to sand out and still keep the shape I want . Is it OK to use lightweight spackle to fill them or should I just let them fill with resin on the lam coat??? These grooves are about 1/16 to1/8th of an inch deep and the same width, also their 2-3 ft. long … On the rail from when the blank was made . I’m going to use Poly Resin … if it makes a difference… Thanks in advance … Board #2 Don J…

try a heat gun first, or hair dryer. Dents will lift out, tears will not - so it depends if the foam is pushed down or gone. Just don’t overheat it or the foam will melt.

ive used spakle but really try to avoid it …it fills the gap and seems plenty strong if used in small areas…but you can see the color difference a little…

Arrrrgh! Don’t spackle. Go the heat gun first, almost melting the foam, should pop out any compressed areas. Don’t over-heat as the foam will char to a yellow color (and give off toxic fumes). There was only one kind of spackle that will stay white when you use polyester, I think it was called MicroLight but I can’t confirm. Just avoid the headache and heartache of using the wrong spackle…

so then what would you use if you got those worm hole looking things (see picture below) that pop up from time to time… I use to use the light weight spackle stuff but I find it is harder than the foam and sands out weird…plus it doesn’t take paint the same as the foam…

Those pock marks are from the blank manufacturing. While pouring the foam sometimes the worker will take too long or spread a layer of the expanding foam back on itself, trapping air. I get those from time-to-time as well, and I have been just building them right into the character of the board. I explain to any concerned customers that their board is hand-built and much like patterns/knots in wood those marks are a thing of beauty. If I get one over the size of a dime, then I try to get comped from our blank supplier and make the board anyways, seeing if the customer even cares. With all that said, if I am seeking perfection, then it is possible to use some very clean/fresh foam dust (not off the floor/very clean hands) to fill the voids and just lam right over them. If I use resin tint, then I just build the thing with “character” as much as I want the thing to be insane… Good Luck.

Thanks PlusOneShaper… that was helpful… I will try the super clean foam dust in the holes method…

There is some stuff made specifically for filling voids in the blank… see our friends at Fiberglass Supply. Finish sand the blank, fill the hole just flush (use a credit card, razor blade or something to smooth it out) and glass it. Don’t try sanding the “repair”, it will only make matters worse. A bit of foam dust, resin and white pigment will do the same thing.

<img src="" alt="" class="bb-image" />         <div style="text-align:center">Item #</div>  <div style="text-align:left">Solarez Microlite-White, Clark Foam Repair Putty, a white putty of high strength U.V. cure resin and super lightweight additives that effectively repair Clark Foam.  Gels in 30 seconds, curing in 3 minutes, but only when exposed to sunlight.  Upon hardening, it provides excellent sanding and fairing properties. </div>  <div style="text-align:center"> Each </div>   <div style="text-align:center">E32-2517</div>  <div style="text-align:left">2 oz. Tube, Solarez Micro-White (77420)</div>  <div style="text-align:right"> $     8.00 </div>   <div style="text-align:center"> </div>  <div style="text-align:left">Contact us for quantity pricing.</div>  <div style="text-align:right"> </div>

Check the archives…Herb Spitzer has a fix using sugar and something that works for him…

I am reshaping an old board I had made from a clark blank in 2001, I was able to take all the glass off with very limited damage to the foam. But theres still a few areas that could prove to create a few issues while glassing. I am going to glass with poly resin and do a dark blue resin tint.

Can I use fast and final to fix the little voids, if I glass with poly?

Will the dark resin tint cover over any color diferences in the foam?


A dark blue tint is only for the very best glassers to tackle.  using  old recycled blank with holes in it, then doing a dark blue tint…will not work, and will not urn out like you are anticipating

 Dis-similar materials will have dis-similar results, you can’t use fast and final on poly, they absorb resin at different rates. if you use fast and final, the poly will soak into the spackle and will be really dark.  There is really nothing you can use to fill a poly hole in a blank, it will always look like a hole filled with something and then turned out dark…or light, or smeared, or whatever. Always looks like crap, always looks like you filled a hole with crap then laminated over the crap.

Just go with the holes, or make the board clear.  You should know better than to use bad foam for a pretty board.

The only option is to use opaque resin, that will black out the problem, but i’m assuming that since you are reusing a blank, then this is your first attempt at board building.  if you go the opaque route, make sure you use enough pigment.  Put in 2x the amount you think is right, and it might black out the worm holes.

The heat gun works well on dents and impressions, where the foam is still there but puched in.  Otherwise — If it is a scratch or worm-hole;  Liteweight spackle is a good option.  Buy the stuff that is so puffy and lite, it feels like there is hardly anything in the can.  Here’s the trick;   Dab it onto the hole or scratch very lightly with your finger and DO NOT SMEAR it.  Do not spread it to the adjacent surface next to the hole .  Just lightly dab on the hole or scratch only.  Let it dry COMPLETLY overnight at least.  Then lightly screen it with screen and a block.  Bring the spackle down flush with the adjacent foam.  On a Clark; only a trained eye will find it.  If you do it right it will show only so slightly on a painted or tinted blank.  Used this trick alot after Clark closed on Elova Foam Blanks that were being brought in from Argentina to Maui.  Full of “Worm holes”.  More noticeable with super white blanks like Arctic, US and Millenium.   Tints(especially dark blue) should never be done over some old recycled blank that was stripped leaving pock marks.  It will look flat out shitty.  Spackle is for minor stuff.  Always use a first class blank, screened until it feels like silk for tints.  No Scratches, worm holes etc.  Nada.    Lowel

Thanks for the help guys. I would normally start with a new blank but this one has a lot of sentimental value.

The more I think about the discoloration issue the more I like the idea of a resin splash. Seems like to me with all the different shades going one you would never be able to spot the issues.