My first and second kitchen built skis

MaRuMo · Post by **MaRuMo** » Fri Oct 24, 2008 11:01 pm

I remember the last few pairs we used a black re-usable sticky strip to seal the bag, which was one of our Swedish friend's idea. I don't know what it's called but it was really effective and like plastic clay.

davide · Post by **davide** » Sat Oct 25, 2008 6:32 am

I saw you are cutting skis by hand. すごいですね。
私もスかたばでキーをきりました。

Just a question about the cores you got from me. What do you (and Idris) think about the flex? Tip is soft or hard?

MaRuMo · Post by **MaRuMo** » Sat Oct 25, 2008 10:09 am

初めまして。日本ののこぎりは子供の時に使って以来なので、なつかしかったです。

I found the ski overall relatively stiff to ski, as I guess I'm on the lighter side, and not aggressive skiing yet, but springy. The flex at the tip was softer than the overall stiffness. Somehow it all worked well, and the tip bend turned out nicely (wasn't able to replicate the same bend in the next pair) so the skiing on your cores were great. I'm appreciating it more and more as my skiing improves.

It's also a beautiful core. どうもありがとう。

skiingfreak · Post by **skiingfreak** » Sun Nov 09, 2008 9:46 am

Are you using the same method to bend your masonite that you've used to prebend your cores? I think that was you that steamed your cores and let them set in a jig right?
Do you have any photos of the bending process?
Thanks again. I'm pretty close to bending and want to make sure I'm using a good approach.

MaRuMo · Post by **MaRuMo** » Sun Nov 09, 2008 1:45 pm

Hello Skiingfreak,

Yes, we've bent the mesonite the same way using the same jig as prebending the cores, which is what I think you've seen. I have a few pictures, of the jig and with the mesonite in it, but it's the same as with a ski core in it. Just make sure the jig is wide enough for the mesonite to fit in, which is wide enough to comfortably fit two skis beside each other. The mesonite (or something similar) we used the second time didn't take the soaking very well and bubbled, cracked etc. when it was being put into the jig. The first kind mesonite we used was quite strong and didn't mind the water at all, and only got soft enough to bend into the rig easily. You'd like a material that will be nice and flat with a prebend in it.

Soak what you need to prebend a little beyond the point you want to bend to make sure it is warmed up nicely to become flexible. Wipe excess water off and leave it to cool gradually and dry out. Unless you're in a rush, I'd recommend leaving it in until it's gotten back to it's original character (dry and stiff). It may loose a little of it's flex once it's been released from the jig. You may want to round off the edges of the braces/bars as it may leave a mark/groove in the core, or make the section where you slide in the material wide enough to accommodate a thin continuous layer of something (plastic maybe) to keep the surfaces smooth (it's sandwiching the core/mesonite in the jig). This should also help support the material you want to bend, from cracking under stress and bending it into the jig.

Good luck.

skiingfreak · Post by **skiingfreak** » Fri Nov 14, 2008 9:57 am

Well, I sucessfully bent a test piece of masonite this week. I had it ready to go for a test layup which I ran into a problem with (plywood doesn't bend to easily...). Anyway, I let the piece of masonite sit for a few days while I was working on some other stuff and I noticed last night that it's lost about half of it's curve. I steamed it for probably 20-30 minutes over a pot of boiling water before clamping it down in my jig for maybe 18-20 hours. When I pulled it out it held most of it's shape for at least a full day. Two days later I went out to check it out and it was flattening out. Could this be because I didn't steam it for long enough? I was thinking about using the soaking approach but I read on some woodworking forums that it's the steam and heat that allows the fibers to relax in the wood, not actually the water. When you're soaking your wood are you using boiling water to soak it or something?
Here are some pictures: http://picasaweb.google.com/skiingfreak ... ngMoldTest#
Thanks again!

telexis · Post by **telexis** » Fri Nov 14, 2008 10:34 am

I had similar problem with 1/4in masonite...

I end up using an knife to cut lines about 1/32in deep on the back of the board. Then it bends pretty easily...

I had to glue it anyway on the mold, so I just put a lot of glue on the line that I cut and it is now pretty solid!! ;-)

I am not sure how masonite would react to that technique...

Alexis

skiingfreak · Post by **skiingfreak** » Fri Nov 14, 2008 12:34 pm

Good solution! The other part of my problem though is that I'm using it in a vacuum bag as my form so I need it to hold it's shape.

ben_mtl · Post by **ben_mtl** » Fri Nov 14, 2008 1:40 pm

What I did is to hold the masonite sheet to the mold frame with screws, i don't even pre-bend the masonite. 4 raws of screws with a 6in spacing and it's perfect, I just countersink the holes for the screws so everything is flush, then bond a sheet of laminate (formica) on top of the masonite. It works just well ! I made 2 molds that way and had no problem.

On the first mold, I tried filling the small gaps where the screw are with car putty prior to bonding the laminate but it's a pain to do and there is absolutely no noticiable difference compared the 2nd mold where I didn't do that.

skiingfreak · Post by **skiingfreak** » Sat Nov 29, 2008 1:02 pm

Since I'm using the masonite as my mold (nothing underneath it in my vacuum bag) anyone have ideas on how to do a better job of pre-bending it? Basically I need it to hold it's form on it's own once I remove it from the jig. My method was to steam it over a pot of boiling water for probably 20 minutes or so then clamp it down to my form. I tried again this afternoon by running it under hot water so it got soaked a bit as well.
How do those of you that use a vacuum bag rather than a vacuum table pre-bend cores?

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My first and second kitchen built skis