Where are you located you can’t get higher quality foam? There’s gotta be a better supplier somewhere. I don’t mean to be negative but I wouldn’t waste resin on 1 pcf.
Speaking from experience btw. I made a board a long time ago when I started out with 1.5 pcf. It sucked. However I did a vented leash plug and it never delamed and I still have it today.
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This is making me optimistic about it thanks for the insight I’ll be looking into that.
Well I’m glad you’re being real about it because I am looking for advice. If I do a heavy glass coat and vent it do you think it’d be fine? I live in Arizona. Someone probably could find some better foam but from me looking around I couldn’t. I also got everything for free so far so worst case scenario I don’t lose any money I’ll just be disappointed. Do you think if I do the carbon vacuum bag thing that it would work and be fine? My board probably won’t be amazing even if it does work but it has been fun to work on and dream about. Thanks.
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I also used this foam because from my limited research I thought that it would be fine. I knew it wasn’t ideal but I’m still optimistic it will work.
I’d glass it heavy considering it’ll be pretty buoyant anyways due to the foam, when I did 1.5 pcf it was very floaty. I’d spackel the board as well prior to glassing and install one of the vented leash plugs.
I can’t speak to vacuum bag method I’ve never done it but I’m sure some of the vets on here can help you there.
I did a board with this. It wasn’t easy to work with.
It delammed pretty quick. I really should have used a vent, but even with that I have little faith in it. Did a normal glassing schedule.
Then I did one with pink xps. That was a lot, lot easier, but heavier, because I didn’t lighten it with holes.
The xps was easy to bind to the glass with a pin roller.
If I were you, I’d switch to xps. If this weak eps is already shaped, remember the vent and glass a little bit heavy I guess.
Thank you cjohnnymac. This stuff has taken me on a ton more research and I’m gonna keep learning about this stuff before I try anything. I am currently agree with you that if I spackle it and use heavy glass and vent it that it would hopefully be fine. I am also looking into the vacuum bag method. In the end I’ll do what I think is easiest because I’m not very skilled with this stuff. I think I’ll be able to figure the rest of this out I just needed a direction for more things to learn about. If I mess it up bad or am completely confused then I will ask more questions but hopefully I don’t need to. Thanks again so much for the advice.
ShaperSupplyCo’s recommendation sounded solid.
You could also use S-glass instead of E-glass for a stronger shell.
Do some testing on scrap foam first.
WMD/Compsand Tech
Thank you so much stoneburner I will look into the s glass and those videos. You guys have been so helpful.
If you don’t have all the materials for the vacuum bag, maybe you can try something like this
Hey, just to throw another option into the mix, instead of a wood veneer you could use cork or a thin layer of a high density foam to ‘wrap’ the shaped blank in before glassing with a more traditional schedule. I have made several boards with sub 1lb foam, wrapped in cork and glassed as normal. They hold up well.
Cork is a great impact absorber.
My concern would be that it has lower compressive strength than wood veneer.
I’ve done many EPS boards. I stay away from using soft foam and stringers because they always end up with problems along the stringer. The softer EPS tends to tear a lot when shaping and you have to put more spackle to fill voids before glassing.
I’ve made stringerless EPS boards with 1.5 pcf and 3 layers of 8oz glass and they had quite a few heavy pressure dings on the deck after the first use.
If you live in the US, or anywhere that Balsa is available, you can buy a couple of pieces of model airplane balsa about 1/8th inch (3mm) or 1/16th inch thick by 3" or 4" wide and lay that over the stringer to keep the stringer from breaking through the deck lamination. I use use Gorilla Glue or another foaming PU glue, tape and small bricks to hold down little pieces of balsa on the foam. You’ll hjave figure out how the edges are smoothed down to meet the foam. You could route the blank or smooth the wood down along the edges. That would be a problem if you are finished shaping.
You would need a vacuum system to do a full deck covered in veneer. I usually vacuum bag (with epoxy) a full deck veneer over softer foam and it’s very strong, no pressure dents.
I have not used vents, except on hollow boards, and yes, I have had several bad delams. I think the delams on the EPS foam were due to poor work, but delams on my XPS boards were from heat.
Low cost materials will always require more work and creative ways to get good results. I think it’s best to get decent blanks if you are starting, and then get creative as you get more knowledge.
Except for the cost of the foam, resin fumes and clean up (acetone), a PU/PE build is still way easier than an EPS/Epoxy build.
Thank you all. I have a question about a potential plan.
I’m thinking that I spackle the current blank and fill in between the beads. Then I would get the 1/8 balsa wood and layer it over everything. Would it work to just use a wood glue like gorilla glue for that? I would clamp it down and apply pressure. Then I was thinking 2 6oz on top and 1 6oz of fiberglass on bottom. I would also make sure to vent it so it doesn’t delam. Do you think that would work?
Or would I have to have a layer of fiberglass in between the wood and the foam?
In my mind it seems like this plan would work and it would limit the complexity of the vacuum bag. I don’t have the stuff to do that currently and I’m not confident that I wont just mess everything up that way.
1/8” balsa would be too thick for veneering the entire surface of your blank. Shark was talking about a balsa strip covering the stringer on the deck side.
The old Bert Berger thread had the correct thickness for an entire balsa veneer cover.
The wood is mainly going to keep the pressure on the stringer from breaking through the glass. You don’t need to spackle before you glue the wood on. Use Gorilla glue or another foaming PU glue, but don’t use a wood glue, you can use an epoxy. Also don’t let the glue spill out from the edge of the wood. That will create a hard spot and sanding it will make an uneven area. You also don’t need to lay fiberglass under the wood. Once the edge of the wood is sanded smooth to the foam, you can glass with 2 layers of glass. I would do 2 layers on the bottom too, the foam is too soft to make a strong shell with one layer of glass. I also put wood in the foam where the fin boxes will be. I put 1/2" pieces running perpendicular to the fin box about 4 inches long. Sometimes 2 pieces to extra strength. This will keep the boxes solid. I have had boxes tear out from just making a hard turn without the extra support. Or, you can use boxes that are set before glassing like Futures or FCS fusion and FCS 2. I like boxes because I’ve had boards delaminate under the fin and then it’s a nightmare repairing that.
I just use small bricks like little paver bricks to hold down the wood for a single width of wood. When I vac bag wood onto foam, I put a layer of glass under the wood, but I create a skin to cover the whole top. I use thin masking tape to hold the wood pieces together. I tape all the edges tightly together and put the tape side against the board with a clean wood surface exposed. This keeps resin from going through the seams.
The vac bag opens a whole bag of tricks for making boards. Most high end wind surf boards are laminated in a vacuum bag for strength. You can get the resin to glass ratio down to 1:1 and many times you will have a nearly finished surface. I haven’t laminated a board in the bag, I just use it to vacuum wood veneers onto the foam.
One thing I do occasionally is to glass the board with just a single layer of glass on the deck, then add the wood skin in the vac bag, and laminate another layer of glass over the wood. For a true Composite Sandwich, you want fiberglass on both sides of the wood.
Now after all this, let me say that if you use too soft of a foam for the core, you will eventually have failure and either soft spots, or a broken board. The oldest of my soft foam core compsand boards have many soft spots. I don’t know if they are delaminations or just the foam being smashed down. But I made those boards in 2005 or 2006 and probably got more than 5 years of use before I noticed the soft spots. I still have those boards, but I rarely use them.
Good luck!
We use 1/8" Balsa as skins on our compsand boards, but they are full width/length skins. 1/8" is solid like having 20 oz of glass once the board is done, but much lighter. 1/16" is good if you have a heavier core like PU foam. I use 1/16" on 1.5pcf EPS.
Finish up as cheap as possible and it’s a practice board. Then spend on top quality materials next time. Your labor is the most expensive ingredient.