cheap molds / prototyping

[ben_mtl]

I've been away from skibuider for quite a while now (at least from my point of view) due to the building of my new garage/workshop and lots of other stuff I had to take care of.. The workshop is almost done, still ned to finish the vapor barrier and hang the drywall but as temperatures are slowly dropping my mind is more and more leaning to the ski / skibuilding !
My press and other tools are still in boxes for now but I'm already thinking about what's gonna happen to my "production" this year !

One of the thing I'd like to work on this year is to try a lot of different shapes. Even hough I have my templates CNC cut, it might not be a big deal to tweak my templates "manualy" to play with the sidecut/width/length/taper and so on.

What's more tricky I think is to play easily with the underfoot camber (or reverse camber) and differents shapes in the tip/tail rocker/early rise.

As some of you know I have a press with a large fixed camber mold and on top of which I put different tip/tail blocks depending of the ski I make.
Those blocks are made out of MDF and are solid blocks (profile is cut 15 times and all those slices and glued together). Making those blocks is not cheap as it takes quite some MDF and is really long and nasty (MDF dust) to make.

Does anyone have some suggestions on how to make "disposable" tip/tail blocks. I just need to make let's say 3 pairs of skis with each shape and if it's a GO I'll make one block out of MDF. Making one ski at a time to make is cheaper is definitely an option but I dont't know how I would do it in my press as the 2 bladders are inflating together.

In other words how do you guys proceed to change you shapes easily, I was even thinking of going back to vacuum for prototyping as vacuum molds don't need to be as sturdy as for a press, thus making them slightly easier to make. But I would have to buy some other resin (mine is made to be heat cured) and struggle again to find an easy way of maintaining the vacuum for almost 24h without being watching for leaks all the time (with a heated press it's ways faster and easier to press).

Anyways let us know what your thoughts are, I'm sure a brainstorming on that could be beneficial for lots of us.

Thanks !
Ben

[WhitePine]

Check out this thread.
http://www.skibuilders.com/phpBB2/viewtopic.php?t=1307

It looks like people have had success with Doug Fir, plywood, 2x4's, etc. It may be less precise due to the grain structure. The variable wood grain may cause slight deviations due to heating and humidity but people seem to have used them successfully. And since you are prototyping I'd say use whatever you want. But then again, I'm new to ski building so I'd what for others to chime in.

[sammer]

Hey Ben glad to see your back.
I think for prototyping vacuum might be the way to go.
3/8 mdf bends really nice curves and is easy to support.
I'm still using 1/8" puck board to skin my molds. It works really well and epoxy doesn't stick too bad.
A sheet of mdf and one of puck board wouldn't cost that much and will make quite a few molds.
I'd love to have the room for a proper press and give up the vacuum but for the time being its working for me.
I'm in the process of buying a new (to me ) house with a garage then I'll have to see about a press

sam

[WhitePine]

Sam. Where did you find your Puck board? I see there are lots of hockey stores online that sell it but local is always better. Puck board is just a fancy way of saying HDPE right. Or is there some extra additive that makes it slippery?

[sammer]

Sam. Where did you find your Puck board? I see there are lots of hockey stores online that sell it but local is always better. Puck board is just a fancy way of saying HDPE right. Or is there some extra additive that makes it slippery?

Yup, HDPE as far as I know.
I buy it at my local building supply, although I'm not sure why they stock it.
It works really good for my application, not sure I'd be using it in a heated press though.
It doesn't like heat to much, warps like crazy.

sam

[ben_mtl]

As soon as I'm done with the shop and I've pressed a couple pairs (just to be sure I still now how to do) I'm gonna try to make a tip mold out of 2x4... surprizingly I have quite some leftovers of this kind of wood :p

I might also look again into vacuum.. I don't have my pump anymore but I might end up buying a new one anyway as it was very helpful for glueing core blanks.
Back when I built my first pairs I did a pretty cheap mold out of plywood + sheet of masonite on top.. it worked like a charm !
One thing I have to figure out is how to easily apply heat to a vacuum setup, I'm sure there are a couple examples on this forum, just have to use the search function !

[chrismp]

take a look at OAC's posts in his journals and the equipment section. he has gone through a couple of ways to heat a vacuum set-up.

[prospectsnow]

I've spent a fair amount of time on silverfishlongboarding.com. Their forums have a section for people that build their own skate decks. The people that build on there are a simple version of what we have here. The presses are often wood with ribs. These guys usually slap together a press for $20 and $100 is considered to be expensive.

The guys that keep it really cheap use Styrofoam insulation and cut out the form blocks, most of the time with a hand saw. If you were to laminate these together it would probably only cost $5 at most for a tip section if you don't have any around. It may not be able to take 80psi either, but it is pretty tough and should last long enough to make some protos.

[WhitePine]

Prospect - out of curiousity what pressures do longboarders press at?

[prospectsnow]

pressing longboards was practice for building snowboards. My press was pretty simple so I had no tools to measure actual pressure, but enough to break some 2x4s. Also enough to bend concave and make drop decks.

[shockstart]

You should get back and enjoy skiing again man..

[chrismp]

yeah man, you really should...to bad you're into snowboarding