What are the respective benefits to the different methods of sealing EPS blanks? I have heard of a couple that I am considering using on this board, these being 1.the microballons/epoxy mixture and 2.a lightweight spackle. I see where the epoxy/microballons would give a better blank/glass bond, but might be harder to sand? The spackle would probably be easier to work, but I’m concerned about the bond when I get ready to glass… Don’t want any delams for that reason. Also to consider, the board has plenty of little BB-sized voids I need to fill as well as some chunks where I’ll need to fill and reshape little bits of the rail, so I need to think about that too.
So, to those who have done EPS/Epoxy before, what is your best advice for a fill/sanding coat?
I’d say use the epoxy slurry but use Peelply for ease. For Peelply get some “Breathable Nylon Taffeta Uncoated” from your local textile district for a buck a yard. Same stuff they use to make jacket linings with. You MUST make sure it uncoated or the resin will not bleed through. Also get it in pure white, cuz colors will bleed off. Use a squeegee on it to smooth things out. Pull it off after the gel, not to early but not too late. You’d might have to sand just a tad to get rid of all the amine blush. This is from boat building experience with epoxy, but I’m sure it would work with this application.
I use lightweight spackle mixed with distilled water. This is Loehr’s suggested method, no delam problems, lightweight, cheaper, and easier. Do not use tap water!
I like using an epoxy to seal with, it bonds with the surface and gets into the pores. I don’t blow off the blank before sealing and the dust in the pores become an EPS putty that is soooooooooooo easy to sand. Then I squeegee coat it again and that looks like a gloss, light sand and you’ve got the super thin/lighweight lamination
Yeah, after my last post I found Greg Loehr’s suggestion and since I’m going to be using his epoxy, I figured I’d do it his way. My spackled board is drying as I type, but I am afraid I do have one question…
What happens when you use tap water to thin it out?
The minerals and other impurities can cause a little yellowing or strange patterns. Any grocery store will have distilled water. Another tip: let the spackle dry completely or you will have lam problems.
You are saying two coats of epoxy sealer, drying between each and sanding after both? Can you airbrush on top of that, or should you airbrush the foam before the sealer?
From your current post and your previous, I am gathering that even with 6 to 9 more oz’s of epoxy, the net result will be a lighter board since it won’t soak resin during the lamination?
Yeah, I did tape off the stringer… At least I didn’t screw that up! Got to keep that 3/4" red cedar lookin’ clear!
This whole board is pretty much an experiment, this is my $16 blank, so no biggie if the tap water discolors it a little. Just as long as I don’t get delams.
On short boards I am using 3 liquid ounces per side for the first coat, the second side uses so little with it being alrady so smooth. I think you could do a spray on top of the second sealer (Greg sprays cheap enamel over the lam and it sticks). I use a drop of white in my sealer, it make the look of bead foam vanish. My goal has not been to build pretty boards from bead EPS, so I haven’t been on a color trip. Right now I am trying to get as light and strong a board as possible. Some of the boards I have done have weighed out at 4-1/2 & 5 pounds for 5’8"s. 6 pound 5’10’ @ 2-3/4" thick and a 9’0" @ 12 pounds and a 4 stringer 9’2" @ 14 pounds. I just did the glass on fins on 2 Lost boards for Matt Biolas, they are doing tests to see how strong they will be. They had the boards rocker down and were standing on them, with the rocker flattened out, no fractures or stresses
if your not vacumning , peel ply can be a bit hit and miss, you can get areas where it gets to dry , plus you have difficulty seeing your work ,
in a vacumn your work is automatically quality controled , as the even pressure will wet out dry spots and even out wet spots …
jim … eps is good like that … it can bend along way , tolerate a huge range of shear movement and not do any lasting damage …the secret there is not penatrate the foam to deep , then you allow more shear movement, if you allow more resin to soak in , you get slightly better dent resistance , but the less range in shear movement means it becomes more brittle and snaps easier…
that fact you keep resin penetration to a minimum is one of the biggest reasons they can bend further without breaking…
regards
BERT…
glenn im going to your thread now …
it could take a while to answer all those questions …