Polycarbonate top-sheet

PIPO · Post by **PIPO** » Wed Dec 24, 2014 3:04 am

Hi, has anyone tried using polycarbonate as a top-sheet? I've found a local supplier in my place that has 1,5mm thick UV treated clear polycarbonate sheets.

I found a couple posts saying PC bonds as well as ABS (or little better), so guess it could be a solution. Any suggestions?

Thanks for your time!

chrismp · Post by **chrismp** » Wed Dec 24, 2014 6:37 am

1.5mm is way too thick and heavy as a topsheet. Usually, topsheets are about 0.5mm. I think PC would also be too brittle and crack easily.

PIPO · Post by **PIPO** » Wed Dec 24, 2014 6:51 am

True... I was seduced by the idea of having UV treatment but yes, it's way to thick.

What about PET?

OAC · Post by **OAC** » Wed Dec 24, 2014 7:03 am

Polycarbonate is for hockey rinks!

If I were you I should start with varnish/laquer. 2-c polyurethane.

But, you don't have to fear that the UV dissolve your skis before you're tired of them and/or built new ones.

PIPO · Post by **PIPO** » Wed Dec 24, 2014 9:25 am

You mean no top sheet at all?
I was thinking in using screen printed graphics and another layer on top of that.
So you say press with fabric on top and then varnish once removed from the press?

skidesmond · Post by **skidesmond** » Wed Dec 24, 2014 10:44 am

If you're feeling real brave... I did some experiments with plexi-glass and acetone. It's in the forum somewhere. Not exactly sure what kind of plexiglass it was but it's the material used in screen doors, could have been a poly-carbonate.... Anyway, acetone melts the plexiglass. You could try coating your ski with that. In my experiments it would dry too fast. Then there's the dangers of acetone... Just don't get it on your skin and work in a well ventilated area.

Epoxy, poly-u or LPU (Linear Poly-u) al work over graphics or fabric.

PIPO · Post by **PIPO** » Wed Dec 24, 2014 1:47 pm

skidesmond wrote:If you're feeling real brave... I did some experiments with plexi-glass and acetone. It's in the forum somewhere. Not exactly sure what kind of plexiglass it was but it's the material used in screen doors, could have been a poly-carbonate.... Anyway, acetone melts the plexiglass. You could try coating your ski with that. In my experiments it would dry too fast. Then there's the dangers of acetone... Just don't get it on your skin and work in a well ventilated area.

Epoxy, poly-u or LPU (Linear Poly-u) al work over graphics or fabric.

mhmmm... sounds interesting, however it's gonna be my first pair ever :P how would you suggest doing that?

anyways, what I want it's just a transparent top-sheet... but not sure about the material and thickness.

OAC · Post by **OAC** » Wed Dec 24, 2014 2:30 pm

Agustin wrote:You mean no top sheet at all?
I was thinking in using screen printed graphics and another layer on top of that.
So you say press with fabric on top and then varnish once removed from the press?

Yes
If this is your first pair, focus on the basic parts like aligning the core, attaching the edges, getting the tip/tail spacers in place, wetting the fibers etc...
Top sheet sometimes adds unwanted parameters like extra weight, extra stiffness if you don't know your material and it dosen't hurt to start with the simplest. Believe me.

But if you feel for trying other material don't hesitate! Try and test that's whats alot of this is about!

Good luck!

chrismp · Post by **chrismp** » Thu Dec 25, 2014 3:29 am

If a transparent top is what you're after, either get one of the many varieties of ski/snowboard specific transparent topsheets, or press with no topsheet at all and add a couple of layers of two component polyurethane varnish.

skidesmond · Post by **skidesmond** » Thu Dec 25, 2014 6:35 pm

Agustin wrote:
skidesmond wrote:If you're feeling real brave... I did some experiments with plexi-glass and acetone. It's in the forum somewhere. Not exactly sure what kind of plexiglass it was but it's the material used in screen doors, could have been a poly-carbonate.... Anyway, acetone melts the plexiglass. You could try coating your ski with that. In my experiments it would dry too fast. Then there's the dangers of acetone... Just don't get it on your skin and work in a well ventilated area.

Epoxy, poly-u or LPU (Linear Poly-u) al work over graphics or fabric.
mhmmm... sounds interesting, however it's gonna be my first pair ever :P how would you suggest doing that?

anyways, what I want it's just a transparent top-sheet... but not sure about the material and thickness.

LPU from System 3 dries clear, not cheap, around $60 a quart. Dries extremely hard and dries quickly. Apply 3-4 thin coats. You can also use automotive clear coat spray. Clear top sheets can be expensive and some are not real clear to begin with. Keep it simple for the first handful of skis.

PIPO · Post by **PIPO** » Thu Dec 25, 2014 7:49 pm

skidesmond wrote: LPU from System 3 dries clear, not cheap, around $60 a quart. Dries extremely hard and dries quickly. Apply 3-4 thin coats. You can also use automotive clear coat spray. Clear top sheets can be expensive and some are not real clear to begin with. Keep it simple for the first handful of skis.

Keet it simple, that's what I want right now for my first pressings. I thought that a clear top-sheet would be a simple thing, but guess I'm wrong. So you say painting with polyurethane is my best choice right now?

Do you remember what have you used as top-sheet layer over your graphics in your first skis? Or you just didn't use graphics at all?

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Polycarbonate top-sheet

Polycarbonate top-sheet