Clear topsheet and Veneer

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Gumby
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Clear topsheet and Veneer

Post by Gumby »

First post on this site, have spent ages reading posts.

Have successfully pressed my first set and now want to press a set with a clear top sheet and veneer underneath.

Do you guys that are pressing sets with a top sheet and veneer subtract the thickness of the veneer from your cores.
gozaimaas
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Post by gozaimaas »

I say no. A veneer will add something but its more like dampness than stiffness. Stiffness comes from how much thickness there is between the sheets of fibreglass and the veneer adds nothing to that.
Dtrain
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Post by Dtrain »

The veneer will add a tad stiffen in my opinion. I just tried to do a clear isosport nylon topsheet over veneer. I got a little delam in the tips when I flashed them. I then processed to rip the entire Clear Topsheet off with a pIr of plyers. I suspect you need a veil or some other layer in there to hold epoxy.
Twizz did beautifull pair with no issues mentioned. Cosurfer has done the same and mentioned getting air pockets of some sort.

Mine looked rad. But when I can grab the tip with plyers and peel it off completely with arm strength, that is clearly not good enough. This was def. not a bonding, corona treatment, flame episode.

Just a straight up.....two hard surfaces. Where's the resin go?
gozaimaas
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Post by gozaimaas »

Maybe you need the felt backed stuff Dtrain?
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vinman
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Post by vinman »

veneer will add stiffness to your laminate vs using a plastic topsheet. I'd say decrease core thickness by .3-.6mm to compensate.
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Gumby
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Post by Gumby »

Thanks for everyone's opinions. I have clear Isosport to use on top as well Dtrain so thanks for your results.
twizzstyle
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Post by twizzstyle »

I suppose it depends on the veneer you use. I've done two pairs like this, both using a 1/40" bamboo veneer. I did no compensation in core thickness, and I personally wouldn't recommend it. Any stiffness added from the veneer is going to be negated by decreasing the thickness of the core inside your fiberglass layer.

It's not as simple as just saying, my veneer is X thick so I will remove X from my core. You would need to know the modulus of elasticity of your veneer, and do some proper composite beam bending math to figure out how thick to make your core. I don't think you can precisely remove the correct amount of material to make this worth the effort, its going to be a TINY amount.

Both times I did this, I put nothing between the veneer and the topsheet. The bamboo veneer does soak up some amount of resin. Dtrain - was your veneer "dry" after you ripped off the topsheet?
Gumby
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Post by Gumby »

Decided to do a test piece last night to see if my veneer wet out like Twiz said.

My veneer wet out as it seems very porous, with veneer and top sheet bonded to some glass and left over bamboo from previous cores, bonding seems to be no issue.

Will press a set next weekend with the veneer and top sheet (Isosport) and see how it goes.
twizzstyle
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Post by twizzstyle »

Great!

Keeping bubbles out seems to be an art form. The two times I've done it, I had no issues with bubbles under the top sheets, but I have seen other people with lots of bubbles. I try to lay down the topsheet very carefully, almost rolling it on, to push the air out. Any bubbles left over, I'll use something round (like some scrap steel pipe) to roll the bubbles out.

Good luck!
Gumby
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Post by Gumby »

Thanks Twiz, have a sign guy at work doing a mural on our wall and a heap of new signage, noticed a squeegee type thing he uses when wet applying vinyl asked him to where he got it from he said he would give me one as he had a spare, I was thinking this would be gold for the top sheet to remove excess epoxy and remove bubbles.
athapoto
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Post by athapoto »

Planning to use poplar wood core profiled to 2.5-11-2.5 and a veneer topsheet sealed with marine varnish (maybe more than two hands) is that going to affect my core flex ? the veneer has 0.6mm thickness
pmg
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Post by pmg »

If it is going do affect it, then only very minimal. What really changes your flex is the core profile - the further away the fibres above and below are from each harder, the harder the ski gets. Whats on top of the top fibres doesn't make much difference.
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falls
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Post by falls »

Dtrain: Did you apply epoxy to the underside of the topsheet before layup or apply dry? I think that helps with topsheet bonding.


I usually roll the topsheets down after I lay them on with one of these. I wet the bottom side of the topsheet before applying to the layup, but I don't think they do this is production.
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PTTR
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Post by PTTR »

Ive done a few pairs with veneer and top sheet. No bubbles since I started using the "alotofextraepoxy" technique. I wet out the veneer and then add an extra 200 g of epoxy down the middle. When the extra epoxy is pressed out it seems to bring all of the bubbles with it.
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Post by victim of abuse/bullying »

I use DuraVision 50/50, and I get super clear pressings and high clarity into the lamination level, like this one--uses carbon and Innegra, w/different weave architectures:

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