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Basalt lamination for foilboard - tensile strength with solid balsa core

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Created by Samuellae > 9 months ago, 3 Mar 2021
Samuellae
NSW, 57 posts
3 Mar 2021 11:41AM
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Anyone had experience with laminating with Basalt fibre? I'm looking at using the Basalt Double Bias 4.5oz Cloth on a DIY solid balsa wood core foilboard, about 130x45x3.5.
Was thinking of trying to get away with just one layer all over plus 2 layers around the foil Mount boxes (will use futures strong box).
Eye-balling the numbers it looks like this might be enough given the solid wood core and dimensions....but I'm also thinking I should probably do an extra deck layer to be safe....or some carbon uni tape. trying to keep it eco, so not wanting to go full carbon, but also not wanting to go too heavy. also thinking of using Sicomin GreenPoxy 56 if anyone has experience using this with basalt fibre and hand lamination only - did it go alright?
maybe I'll get into the vacuum bagging one day but trying to get by on hand-lam for this one.

cheers~

CJ2478
NSW, 482 posts
3 Mar 2021 2:23PM
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i have used the double bias 4.5 oz basalt in several surfboards. It is very good for ding resistance but not what I would be going for with the design you have described. because the weave is not tight like regular fabric it takes alot of resin to wet out and you need a layer of 4oz over it to finish it. It will take 3 rounds of filler coat and sanding to finish it without that layer of 4oz over it.

I havent worked with the regular weave basalt but I understand this takes more resin than regular glass as well. when i have used the basalt fibre i have found it quite difficult to wrap tight radii.

I would recommend two 100mm carbon strips on top, one on bottom, 1 full layer 4oz s-2 glass bottom, 2 layers top, then a patch top and bottom of the regular weave orientated at 45 degrees to spread load.

the s-2 glass is also made by colan and available through sanded australia. in terms of value for money, performance and workability i think this is the best fabric out there.

Samuellae
NSW, 57 posts
3 Mar 2021 9:24PM
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Thanks CJ, that's really helpful, I took a look at your photos posted - I see what you mean about the carbon lay up, that looks like a good way to do it. I think I'll definitely add that in then.
Do you notice any flex difference between your wood core lay ups and a Branded factory carbon foilboard?

dbabicwa
WA, 805 posts
3 Mar 2021 6:32PM
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Solid balsa?

Overkill for 3.5cm. Do yourself a favor and use Paulownia. 12mm core with 200g glass and carbon strip 30cm wide on bottom does not bend at all. 120/42 cm 2.4kg

Basalt is heavy as.



CJ2478
NSW, 482 posts
4 Mar 2021 9:40AM
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Samuellae said..
Thanks CJ, that's really helpful, I took a look at your photos posted - I see what you mean about the carbon lay up, that looks like a good way to do it. I think I'll definitely add that in then.
Do you notice any flex difference between your wood core lay ups and a Branded factory carbon foilboard?


I have made 2 foil boards - one with 16mm paulownia core and layup similar to what i described, another with 25mm thick PVC foam core with 5oz twill weave carbon each siide, 2 x 4oz s glass top, 1 x 4oz s glass bottom and 2 x 100mm carbon uni top - both have pretty much no flex (none that i can feel). I have never ridden a branded factory carbon board so dont have anything to compare it to.

on the pvc board i lay the top layer of twill carbon first (on its own without any vacuum) and stuffed up hard trying to wet it out. didnt realise you need to apply resin to the core first because its so hard to wet out. it ended up with lots of bubbles and i peeled about 1/3 of the total surface area off and am unsure about how the strength of the lamination of the rest of it. i patched that area with carbon and did the uni and glass layup seperately which is held to the board by the bond with that first carbon layer (which i am unsure of). so far it has held up fine with no signs of flex. the 25mm pvc is the way to go, very easy to work with, can bend some rocked into it using a heat gun, no mold required.

Samuellae
NSW, 57 posts
4 Mar 2021 11:08PM
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dbabicwa said..

Solid balsa?

Overkill for 3.5cm. Do yourself a favor and use Paulownia. 12mm core with 200g glass and carbon strip 30cm wide on bottom does not bend at all. 120/42 cm 2.4kg

Basalt is heavy as.






Yeah solid balsa, I've got some off cuts around 35-40mm thick, so by the time I plane down will probably get to 29mm which is the same as the depth of Futures boxes. I agree that paulownia/carbon/glass is the superior material combination, I'm just interested to experiment with these alternative materials as a concept board~ There are some trying 100% basalt laminations over EPS core for surfboards, ( instagram.com/rocketace_eco_surfboards?igshid=1txp341ydb1ls ) ....and I'm thinking with solid wood core we would be in the ballpark of strength enough for foiling. With the basalt weight, do you mean the fibre itself is heavy, or the weight of the resin required to wet it out? im thinking of trying some vacuum alternatives such as solid weighed pressure to assist in the laminate surface and resin thickness which I've seen used on some test pieces with good outcomes (might be good for a deck layer before the rail wrapping layer).
All in all though I think im just gona have to make this thing with the base layers and then set up a foil mock-up to stand on it and see if it bends too much then go from there with any extra layers needed. If it needs anymore than 2 I'll reach for the carbon. Have you both just been drilling out the wood and filling with epoxy then re-drilling for the foil bolts? I think I have enough for another smaller tray and I'll try a thinner design without the track mounts on that one.
Also wondering if anyone has tried leaving off the filler coat to use the fibre weave as deck grip? Was it enough grip? And/or will deck pads stick to non-filler coated deck?
And- does a filler coat contribute to the strength or is it just for texture? Usually I've made surfboards and always done it without questioning the need....

CJ2478
NSW, 482 posts
5 Mar 2021 9:28AM
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Samuellae said..

dbabicwa said..


Solid balsa?

Overkill for 3.5cm. Do yourself a favor and use Paulownia. 12mm core with 200g glass and carbon strip 30cm wide on bottom does not bend at all. 120/42 cm 2.4kg

Basalt is heavy as.







Yeah solid balsa, I've got some off cuts around 35-40mm thick, so by the time I plane down will probably get to 29mm which is the same as the depth of Futures boxes. I agree that paulownia/carbon/glass is the superior material combination, I'm just interested to experiment with these alternative materials as a concept board~ There are some trying 100% basalt laminations over EPS core for surfboards, ( instagram.com/rocketace_eco_surfboards?igshid=1txp341ydb1ls ) ....and I'm thinking with solid wood core we would be in the ballpark of strength enough for foiling. With the basalt weight, do you mean the fibre itself is heavy, or the weight of the resin required to wet it out? im thinking of trying some vacuum alternatives such as solid weighed pressure to assist in the laminate surface and resin thickness which I've seen used on some test pieces with good outcomes (might be good for a deck layer before the rail wrapping layer).
All in all though I think im just gona have to make this thing with the base layers and then set up a foil mock-up to stand on it and see if it bends too much then go from there with any extra layers needed. If it needs anymore than 2 I'll reach for the carbon. Have you both just been drilling out the wood and filling with epoxy then re-drilling for the foil bolts? I think I have enough for another smaller tray and I'll try a thinner design without the track mounts on that one.
Also wondering if anyone has tried leaving off the filler coat to use the fibre weave as deck grip? Was it enough grip? And/or will deck pads stick to non-filler coated deck?
And- does a filler coat contribute to the strength or is it just for texture? Usually I've made surfboards and always done it without questioning the need....


if you look in the table you posted earlier, basalt has a higher density than most of the other fibres so there is this. I have only worked with the bias weave and found that takes a good >20% more resin to wet out than regular weave s or e glass. Feedback i have from people who have used regular weave basalt is that it is harder to wrap edges and may require more resin to get it to stick.

The poor mans vacuum you describe could be effective but I would not personally bother. I have vac bagged at 10 inches of mercury with good results. this is about 5PSI = 35kpa ~ 3500 kg / m2, so you need 3500 kg / m2 to get similar results to vacuum and on this basis i wouldnt bother and instead focus on getting a dry laminate with the squeegee.

On my paulownia board i did 20mm holes with a spade bit and filled with epoxy and milled glass fibre - do not use q cell because it has no strength.

i would do the filler coal because another function of the filler coat is to improve durability of the laminate and waterproof-ness by filling in little gaps where water can get in. on a small board like you're making it will only use another 100g or so of resin. water ingress not much of an issue with pvc foam or paulownia but with balsa you definitly want it watertight. i think you would be wasting money trying to stick a deck grip to raw fibreglass weave, water will get underneath it and by pumping mechanism it will delaiminate (similar to potholes in the road)

Samuellae
NSW, 57 posts
5 Mar 2021 5:40PM
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Select to expand quote
CJ2478 said..

Samuellae said..


dbabicwa said..



Solid balsa?

Overkill for 3.5cm. Do yourself a favor and use Paulownia. 12mm core with 200g glass and carbon strip 30cm wide on bottom does not bend at all. 120/42 cm 2.4kg

Basalt is heavy as.








Yeah solid balsa, I've got some off cuts around 35-40mm thick, so by the time I plane down will probably get to 29mm which is the same as the depth of Futures boxes. I agree that paulownia/carbon/glass is the superior material combination, I'm just interested to experiment with these alternative materials as a concept board~ There are some trying 100% basalt laminations over EPS core for surfboards, ( instagram.com/rocketace_eco_surfboards?igshid=1txp341ydb1ls ) ....and I'm thinking with solid wood core we would be in the ballpark of strength enough for foiling. With the basalt weight, do you mean the fibre itself is heavy, or the weight of the resin required to wet it out? im thinking of trying some vacuum alternatives such as solid weighed pressure to assist in the laminate surface and resin thickness which I've seen used on some test pieces with good outcomes (might be good for a deck layer before the rail wrapping layer).
All in all though I think im just gona have to make this thing with the base layers and then set up a foil mock-up to stand on it and see if it bends too much then go from there with any extra layers needed. If it needs anymore than 2 I'll reach for the carbon. Have you both just been drilling out the wood and filling with epoxy then re-drilling for the foil bolts? I think I have enough for another smaller tray and I'll try a thinner design without the track mounts on that one.
Also wondering if anyone has tried leaving off the filler coat to use the fibre weave as deck grip? Was it enough grip? And/or will deck pads stick to non-filler coated deck?
And- does a filler coat contribute to the strength or is it just for texture? Usually I've made surfboards and always done it without questioning the need....



if you look in the table you posted earlier, basalt has a higher density than most of the other fibres so there is this. I have only worked with the bias weave and found that takes a good >20% more resin to wet out than regular weave s or e glass. Feedback i have from people who have used regular weave basalt is that it is harder to wrap edges and may require more resin to get it to stick.

The poor mans vacuum you describe could be effective but I would not personally bother. I have vac bagged at 10 inches of mercury with good results. this is about 5PSI = 35kpa ~ 3500 kg / m2, so you need 3500 kg / m2 to get similar results to vacuum and on this basis i wouldnt bother and instead focus on getting a dry laminate with the squeegee.

On my paulownia board i did 20mm holes with a spade bit and filled with epoxy and milled glass fibre - do not use q cell because it has no strength.

i would do the filler coal because another function of the filler coat is to improve durability of the laminate and waterproof-ness by filling in little gaps where water can get in. on a small board like you're making it will only use another 100g or so of resin. water ingress not much of an issue with pvc foam or paulownia but with balsa you definitly want it watertight. i think you would be wasting money trying to stick a deck grip to raw fibreglass weave, water will get underneath it and by pumping mechanism it will delaiminate (similar to potholes in the road)


Awesome thanks again CJ, so good to save me figuring this out by trial and error haha.
I'll post pics when done~

dbabicwa
WA, 805 posts
5 Mar 2021 10:20PM
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dbabicwa
WA, 805 posts
5 Mar 2021 10:26PM
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The problem with balsa is dents. Youll spend a lot of time and money and effort for not so great result.




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"Basalt lamination for foilboard - tensile strength with solid balsa core" started by Samuellae