New Here and have a question about a core material.

[propellanttech]

I'm new around the forums, and I have a question.

I'm not going to build skis, but I am looking to build some snowboards.

I would like opinions on using polycarbonate for a core.

How can delamination be prevented?

I know the core will need some kind of longitudinal stringers to take out some flex.

Anyone??

James L

[twizzstyle]

Welcome! About half of the folks on here build boards, don't worry it's not just ski building!

What is the reason you want to use polycarbonate?? Are you talking about the clear stuff that is heat mold able? Because good luck bonding that to anything. I've used it as a mold surface before (non ski project)

[jvangelder]

Why polycarbonate?

I've never done any gluing with polycarbonate, however curbell plastics mentions that, with at least the material they sell, its bondable, which i find rather surprising

-Jacob

[propellanttech]

Welcome! About half of the folks on here build boards, don't worry it's not just ski building!

What is the reason you want to use polycarbonate?? Are you talking about the clear stuff that is heat mold able? Because good luck bonding that to anything. I've used it as a mold surface before (non ski project)

Well, I figure it is easily obtainable, and can be recycled.

Also, the board would be almost indestructible.

Yes, I'm talking about polycarbonate sheet, like Lexan, but I would probably use some other brand to save money.

James

[twizzstyle]

Well I've certainly never heard of anybody doing it, you'll probably have to do a few test pieces to figure out the stiffness, thickness, and weight. Seems like it would be incredibly heavy?

[propellanttech]

Well I've certainly never heard of anybody doing it, you'll probably have to do a few test pieces to figure out the stiffness, thickness, and weight. Seems like it would be incredibly heavy?

Yes, I do plan on testing, if I can overcome the lamination issues.

It probably will be heavier than a standard wood core. I hadn't thought of that. But the possibilities would be cool.

James

[propellanttech]

Just as a follow up:

I did some calculations, and the core would weigh: 5.66 lbs

I'm not sure, but that sounds very heavy for a core. I didn't calculate in the holes for the inserts, but the weight saved there wouldn't be much.

James L

[jvangelder]

It does sound very heavy, i belive my complete boards weight less than that

[propellanttech]

It does sound very heavy, i belive my complete boards weight less than that

If you or someone else has a core, a weight would be nice for comparison.

James

[MontuckyMadman]

figure 8-10 lbs per pair of finished skis depending on your core choice and composite and epoxy and pressing.
an acrylic core would also be very brittle, i would think.
Im sure its elongation at break is significantly less than say ash.

[propellanttech]

figure 8-10 lbs per pair of finished skis depending on your core choice and composite and epoxy and pressing.
an acrylic core would also be very brittle, i would think.
Im sure its elongation at break is significantly less than say ash.

I'm working with a snow board, but I understand your reference.

But to correct the brittle issue: I was discussing polycarbonate, not acrylic. They are worlds apart. Polycarbonate @ 3/8 is bullet proof. I shot a 12 x 12 piece of polycarbonate (0.375 in) with a 357 magnum, and it stopped all five rounds. It was less than 6 feet away. It probably wouldn't stop a shot gun slug or a 50 cal. It is far from brittle. I have actually tied 1/8 inch poly in a knot.

The idea here is to have a board which would be very tough. I probably wouldn't even use a top sheet, and use cap construction. That would lighten the board a lot.

Also....I have found a PDF which says 80 grit sanding before bonding is all that is needed.

James

[skidesmond]

Sounds like some testing is in order. I say lay up some material and run some tests. It may bond ok but wonder how well it stays bonded after repeated flexing and twisting. Also put your sample in a freezer or outside on a cold day, then flex. See if it becomes brittle or delams.

[propellanttech]

Sounds like some testing is in order. I say lay up some material and run some tests. It may bond ok but wonder how well it stays bonded after repeated flexing and twisting. Also put your sample in a freezer or outside on a cold day, then flex. See if it becomes brittle or delams.

I guess that is all I can do. I'll just go for it, when I get ready.

I have some other testing I must do before getting deep into the poly test.

Thanks for the idea, of the freezer or cold day. That would definitely be a good idea. I don't want the board to delaminate while I'm riding it.

James

[twizzstyle]

Yeah will certainly be interesting so go for it!

But I'm not sure you need to worry about having a bulletproof board, what kind of scary mountain do you ride at? Doesn't seem to common that cores are the weak part of a ski/board (I say that, while I just had a core failure on a ski... But that was my fault for using the wrong kind of bamboo)

[propellanttech]

Yeah will certainly be interesting so go for it!

But I'm not sure you need to worry about having a bulletproof board, what kind of scary mountain do you ride at? Doesn't seem to common that cores are the weak part of a ski/board (I say that, while I just had a core failure on a ski... But that was my fault for using the wrong kind of bamboo)

Actually, it's all about clear, not bullet proof. I'll just leave it at that.

I'm just thinking about options, and possibilities.

Can I ask, where you got the bamboo?

James