Great site... Great info...
I am going to design my skis today.
Two questions
1. I want to use a simple wood core with fiberglass topsheet, is it possible to extend the fiberglass down the sides to protect the wood or must i leve the wood bare (aside from epoxy or ABS methods).
2. How do you determine the amount of camber? I know the amount of camber I would like in my finished ski, but I would asume that you would need to over-exagerate this in the mold due to the finished ski not holding the exact form of the mold......
Any advise would be great.
fiberglass top sheet
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
1. the easiest way is to use a vacuum press and angle the sidewalls before pressing. The fiberglass won't conform around sharp corners. If you are using a pneumatic press, then you would have to make a topmold that fit perfectly over your core and layup.
2. I think we lose about 10-12 mm of camber when you take it out of the mold.
I'd like to see your skis, send us some pictures when your done
-kelvin
2. I think we lose about 10-12 mm of camber when you take it out of the mold.
I'd like to see your skis, send us some pictures when your done
-kelvin
If you want to protect your sidewalls with fiberglass, you can also try laminating a thin strip of fiberglass to the wood sidewall after the ski is pressed and the sidewalls are trimmed, beveled, etc. After the fiberglass is cured you'll have to trim it up a bit and do some finishing work. And make sure you mask off the topsheet and base material so that the epoxy doesn't stick to them. I'm sure the fiberglass will bond well enough to the wood to protect it, but I'm not sure how this will look.
Another option is to simply put some varnish on the sidewall. I know Igneous, ScottyBob, and Volkl do this for their wooden sidewalls.
Another option is to simply put some varnish on the sidewall. I know Igneous, ScottyBob, and Volkl do this for their wooden sidewalls.
- Kam S Leang (aka Little Kam)
-
teleottley
- Posts: 2
- Joined: Wed Mar 23, 2005 1:32 pm
thanks for the beta...
More questions...
1. Is it requisite to use a top sheet or can I just use the fiberglass, if so, how do I keep the glass and epoxy from adhearing to the press above them.? ...Or is it easier to use a top sheet? If so would you recomend using P-tex base material for my top-sheet as you did with the 'red-october'?
2. Also... I have noted that all of your skis have tip spacers, what is the downside of not using them... or possibly using extra glass in the tips?
Thanks for the info...
I will keep you updated as they progress.
More questions...
1. Is it requisite to use a top sheet or can I just use the fiberglass, if so, how do I keep the glass and epoxy from adhearing to the press above them.? ...Or is it easier to use a top sheet? If so would you recomend using P-tex base material for my top-sheet as you did with the 'red-october'?
2. Also... I have noted that all of your skis have tip spacers, what is the downside of not using them... or possibly using extra glass in the tips?
Thanks for the info...
I will keep you updated as they progress.
I don't think you need a topsheet, although you probably need something to protect the fiberglass from getting cut up by the edges. What you can do is after you take the skis out, sand the top (don't cut into the fibers) then paint/roll a thin coating of epoxy over that. Do that a few times and you should get a nice smooth layer on top. Do one last sanding and protect the epoxy from scratches and UV with either a spar varnish or a polyurethane. I've used system three's wr-lpu (http://www.systemthree.com/p_wr_lpu.asp) on a kayak and it looks great and seems to hold up to rocky beach launches and such, but i'm not sure how well it'll work on a ski top. Let us know if you try it.
To keep the epoxy from sticking to the mold, line it with painter's plastic or a thin sheet of UHMW. Line the top and bottom, because epoxy gets everywhere.
The ptex top seems to bond very well and should be very durable, however it is a little more expensive and heavier.
The tipspacers needs to be something that bounces back on impact. We've never done them out of wood so we don't really know if they make a huge difference, but our skis haven't exploded yet and I know I've hit plenty of trees and rocks.
-kelvin
To keep the epoxy from sticking to the mold, line it with painter's plastic or a thin sheet of UHMW. Line the top and bottom, because epoxy gets everywhere.
The ptex top seems to bond very well and should be very durable, however it is a little more expensive and heavier.
The tipspacers needs to be something that bounces back on impact. We've never done them out of wood so we don't really know if they make a huge difference, but our skis haven't exploded yet and I know I've hit plenty of trees and rocks.
-kelvin
I'm actually riding a pair of skis that was made without a topsheet (the black Ahmo's on the gallery page). I did what Kelvin said and put several layers of varnish on top for some added protection. I know a lot of snowboard companies do this but I'm not sure exactly what type of coating they use. So far I've had over 100 days on them and the topsheet is showing a lot of abuse. Parts of the varnish are scratched off and the parts near the sidewalls are chipped badly. I would recommend using a topsheet. It makes the ski look a lot nicer.
- Kam S Leang (aka Little Kam)
-
Guest
Just use base material for a topsheet if you're doing a vertical lam layup.
It doesn't chip, but rather shaves. Flip a black base over and it's a nice shiny finish. UHMW sidewalls, just rout after cutting off thre excess glass, etc with a jig or band saw. Check Crown Plastics website for their clear Durasurf bases, which they are also touting for topsheet material.
It doesn't chip, but rather shaves. Flip a black base over and it's a nice shiny finish. UHMW sidewalls, just rout after cutting off thre excess glass, etc with a jig or band saw. Check Crown Plastics website for their clear Durasurf bases, which they are also touting for topsheet material.
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x_freeride
reading this, without ski-building experience, but with surf-board building experience I am thinking of pressing your ski's and building the sidewalls using a hand-layup method. It would be a bit more messy, but you don't need a vacuum press and when everything decently rounded I can't see a problem. 2 layers of fine non woven glass with epoxy would make a strong sidewall.