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

[magentawave]

I have a few questions about shaping, spackling, and coloring a 1.5 lb foam blank for building a surf sup please...

1) I want a light weight board but don't want a throw-away board. I plan on buying an off-the-shelf foam blank with the rocker built into it (as opposed to buying big foam blocks). Should I use a 1.5 lb foam blank, or do off-the-shelf blanks exist that are lighter than 1.5 lb foam? If so, do the lighter than 1.5 lb blanks hold up after glassing?

2) Can you use a normal power planer and sanding screens on a 1.5 lb (or lighter) foam blank?

3) Is the spackle used to seal the shaped blank so the foam doesn't absorb more resin than needed, thus keeping the board lighter? Can the spackle also be used for filling in little dings and dents that might occur before glassing?

4) What kind of spackle do you recommend?

5) I want the board to be bright yellow. What is the easiets way to get the color? Paint the shaped blank or add tint to the resin? When you paint the blank, how do you avoid irregularities in the color due to the spackle? (I'm asking because my last two boards had painted blanks with clear glass jobs and there were irregularities in the color on the foam in areas and I'm guessing it was due to the spackle job.)

6) Do off-the-shelf rattle can spray paints exist that are okay for painting the blank?

Thanks! 

[Jradtke]

Use Sherwin Williams light weight quick dry spackle in the green tub. It dries pure white. I also heard Red Devil light weight spackle from Ace Hardware works. DON'T use fast and final something changed with the formula and it is no longer white.

I just finished a board where I painted the spackle sealed blank with Liquitex spray paint from Michaels. $12 a can but with your receipt you should get a 50% off coupon that works for the second can. I think there is always a 40% coupon on retail me not app as well. Liquitex cans come in awesome colors.

[magentawave]

Thanks! A couple questions please:

- I can't tell if this is a green tub or not, but is this the Sherwin Williams spackle you recommended? http://www.sherwin-williams.com/homeowners/products/catalog/shrinkfree-spackling/

- And is this the Red Devil spackle you recommended? http://www.homedepot.com/p/Onetime-1-gal-Lightweight-Spackling-0541/100136499

- How large of a container of spackle will I need to do a 7'-5" ish long board?

- Great tip about the Liquitex paint too, thanks! I wonder if the irregularities I saw in the color of my last two boards was because they sanded through the spackle? Did you see any weirdness after painting the spackled blank?

Use Sherwin Williams light weight quick dry spackle in the green tub. It dries pure white. I also heard Red Devil light weight spackle from Ace Hardware works. DON'T use fast and final something changed with the formula and it is no longer white.

I just finished a board where I painted the spackle sealed blank with Liquitex spray paint from Michaels. $12 a can but with your receipt you should get a 50% off coupon that works for the second can. I think there is always a 40% coupon on retail me not app as well. Liquitex cans come in awesome colors.

[PonoBill]

The biggest benefit of tinting the sealed blank is weight, and perhaps the subtlety of the color. It is difficult to get an even job on a highly adsorbent surface like spackle. Your best bet would be water soluble paint in a HVLP spray gun, but that requires experience to work well. Everywhere you overlap the spray pattern will look darker. Let the painted blank dry a couple of days before glassing--longer is better. If there's any encapsulated water it will turn that area of glass cloudy, and could delam.

Much easier to spray over the epoxy, but you're adding weight with each coat. It can be significant. Pigment and the enamel body is heavy. Again, a HVLP gun with auto paint will work better than rattlecans, but I rarely bother. Good paint is expensive. Worthwhile for your $50K restoration, not so much for a one-off surfboard. Rustoleum works well.

[55NSup]

1. I used blocks of insulation eps less thsn 1.5 lb. And laminate with 200 g carbon twill and 165 g glass twill.  Super stiff and strong
2. Yes you can use planer and screens and 40 grit sandpaper glued to flat wood slats.. I use hotwire and templates to cut out my blank. Planer to cut so- called rail bands and sanding blocks and screen as final on rails.
3. I used light wieght spackel after a ton of research online. You cant imagine the debate over this. I dont have anything scientific, but gut and observations while laminating one board, tells me epoxy with micro ballon mix will be better and more durable result. Easier for me to source too.
4. Easiest way to get brightcolor will be to prime and paint it with International paints polyurethane . Not the lightest, but easy and super durable. http://www.yachtpaint.com/gbr/diy/products/finishes/search.aspx
Smells really a lot, dangerous stuff. Use a high quality carbon and gas mask. You can get a good finish with roller and brush if you have a dust free controlled environment.
5. Rattle can paints can melt eps. Make sure you test it. Ive seen inexperienced people paint a blank so heavy the lamination will delam.

[magentawave]

I'd like to avoid the added weight and extra cost involved in spraying linear polyurethane later so I'm pretty sure I'll just paint the blank.

You mentioned that rattle can spray paint can melt foam but that has to be oil or lacquer based paint, right? Am I correct to assume that acrylic paint does NOT melt EPS?

It seems to me that adding enough spackle or epoxy/microballoons required to seal a blank would add as much weight or more than it would be if I just glassed over the unsealed foam. Please tell me why thats not true.

Thanks for the tips guys!

[surfinib]

Magenta,
Spackle or micro balloons/epoxy adds very little weight. Greg Lohr of Resin Research put his $02. in on a thread about this earlier this year and voted for spackle. I've seen glassers do it both ways and they both seem to work well, the key being that the blank is completely dry before it goes to lamination. From the drift of the threads you've been posting it sounds like you are planning on making a board. If that is the case PM me and we can talk since we are in the same area I may be able to help.

[Jradtke]

That is the Sherwin Williams product I used. I thinned it out. You only need the 32 oz container. When you are done sealing the blank you'll probably have 20 oz left. 95% of what you put on gets sanded off. 

[magentawave]

Thanks everyone! 

What consistency should I thin the spackle to? Maybe if you could compare the preferred consistency to a food item??

[Biggreen]

I prefer to mix mine to a very thin pancake batter consistency. Definitely pours as a liquid. You'll find it'll start to firm up (not dry, mind you) pretty quickly and I like the thinner better because it spreads easy and less to sand off. Can't wait to see that new Vanguard take shape!

[PonoBill]

I like it a little thicker than that. When I thin too much the spackle seems to powder more--that is, after I've sanded and cleaned the board, if I run my hand over it I get a little powder. I like it to be like whipped cream--easy to spread and flatten, but won't pour.

[magentawave]

How many cans of yellow Liquitex spray paint do you think I'll need to paint everything (both sides) of a 7-4 x 27" board?

I just finished a board where I painted the spackle sealed blank with Liquitex spray paint from Michaels. $12 a can but with your receipt you should get a 50% off coupon that works for the second can. I think there is always a 40% coupon on retail me not app as well. Liquitex cans come in awesome colors.

[gorgebob]

I like the spackle like whip cream as well. Use distilled water so it won't yellow. Krylon after you glass is another option and it protects the epoxy from the sun a bit more.

[surfcowboy]

The spackle we're talking about is so light you will think the container is empty. If you pick up the light one and the regular one you'll see what we mean.

[PonoBill]

I added a little dash of vinegar to see if it would stop powdering. I think it helped.