In september I’ll start making board #4 and 5. I’ll make it in XPS and epoxy (stringerless).
Is it a good idea to use microballons in the sandingcoat for better sanding? I’ll also use white pigment in that sandingcoat.
And is it possible to use ricepaper logo’s on te sandingcoat under the glosscoat?
about the shapes:
I’ll make a copy of ci’s “eagle’s wing” 6’7" for myself. I’m 6’2", 183lbs and will use this board in france’s summerwaves and the better belgian/dutch days. Any remarks about this one?
#5 will be a copy of ci’s M4 for my sister.
Ow yeah had a little stupid question too: Is the entry-rocker the same as the nose-rocker?
why microspheres? They are great for sealing but I fail to see why you would want them in the layers above the lamination, do they give compression strength or flex?
horrible idea. no microballoons in the sandcoat. the point of sanding is to get things flat. can’t do that if you keep sanding into microballoons. save the microballoons for sealing eps before lam.
I have thought about adding a little thickener to a hotcoat from time to time… true you’ll use slightly less resin, and I don’t think it will impact board strength enough to matter.
However, microballoons and similar products are silica, and sanding will produce a dust with cancerous capabilities. Maybe you’ll be properly protected by your respirator (and then again maybe not!), but where does the dust go? There have been threads which discuss the composition of Qcell, microballoons and the like, which I have not looked up for this reply. Let’s just assume that the stuff is silica.
About that respirator: in the USA, respirators are rated by NIOSH with with a Protection Factor, defined as the concentration of a contaminant outside the respirator divided by the concentration inside the respirator. Okay, the typical half mask respirator with cartridges gives you a protection factor of 10 (assuming it fits well and you’ve shaved recently). Without checking what the allowable level of silica dust in breathing air might be, my experience sanding plain old polyester boards tells me that you will probably need a much higher Protection Factor. This will require a positive pressure respirator or supplied air system, which is unlikely to be found/used by us backyard types, and it still leaves open the question where the dust-laden air will be sent.
Overall, my suggestion is not to add microballoons, for the sake of your own health, those of others around you, and the environment generally.
Is it because sanding microballons leaves holes? Does it matters if you do a glosscoat afterwards? edit: okay I’ve read charlie’s post and am convinced about the danger of microballons.
And how about the ricepaper under the glosscoat? Or is glass over it nessecairy?
Ricepaper graphics really need to go under the glass. If they are in the hotcoat or directly under gloss there is a high probability that when sanding or polishing you will go right through it. Yup, I’ve done it, and it sucks to consider repairing it.
Microballoons won’t leave visible holes, they’re too small.
yes, sanding microballoons leaves holes. and you shouldn’t do a glosscoat over a hotcoat that isn’t flat. it won’t come out right. and don’t you think a good hotcoat and a thin gloss would be better than a thick hotcoat will microballoons plus an uneven gloss to fill in the mess left behind?
rice paper in the lam. between two layers of glass, or if only one layer, then between glass and foam. put some resin down under the rice paper before setting it in place and laminating over top. it’s possible to do it under a hotcoat or gloss, but chances are that it will get screwed up. it won’t lay flat, the resin won’t go down evenly, and you’ll probably sand through it.
depends on the logo. if you’re tinting, and it’s a light tint that won’t effect the logo, then no worries. otherwise, i’ll do the tinted lam, and then put the logo over it with a 2-oz or 4-oz patch clear. if doing two layers, though, i’ll only tint one layer, then do a whole second layer in clear with the logo underneath. i’m still refining my glassing technique, and i find it much easier to get a good tint with only one layer than with two.
microballoons are glass and designed to be more transparant but it adds more weight than using qcell or something lighter.
If it’s just a fairing compound you’re trying to create I believe qcell might be a better choice…
Herb’s famous diaper dust is another wonder filler option for a fairing compund as well.
If you want to do your graphic on top of your sanded smooth hotcoat then print the graphic on transparancy film like you would onto the rice paper and lay it on a ultra thin coat of epoxy to smooth out the air bubbles and secure the image to the surface. when it’s dry peel off the plastic and seall the image with your gloss coat.
I picked up this hint from the archives from a post by speedneedle
another lamming hint if you’re going the XPS route as indicated…
get a super stiff but not too dense wire brush and whack the entire surface you plan on laminating before glassing the XPS or leave the surface roughed out no greater than 60 grit to “help” reduce delams
we do it with the blue dow xps to improve the mechanical bond and hopefully reduce the out gassing.
also don’t squeeze as much of the resin out of the lam like you would normally on an PU or EPS glass job.
That wire brush is a superb idea! I was thinking about making cuts in the foam because I had some delam problems (solved it by making holes in the skin :P) with my first 2 boards. I still have some XPS, thats the reason of using it. But I’ll do the wirebrush trick! I’ll also wet out the foam under the glass when laminating. I think that helps the bonding too.
And yes it is the one and only dow’s blue styrofoam
MrJ used phenolic microballoons in the “bog” fill coat he used on at least some of his boards. His theory was that it reduced the weight of the fill coat slightly. He squeegeed it on if I’m not mistaken. He also said it made sanding easier.
His boards were quite light. He really didn’t give a shit what they looked like. I give him lots of credit for developing his own methods from scratch and getting good results. He also experimented with offset fins and asymmetrical outlines to an advantage.
Here is a pic of one of his bog coated boards with offset fins…
