cariboo skis

[skibumben]

Hi all,

Ive been lurking a long time on this board! I started a ski building project 5 or 6 years ago, and never got it finished due to house and work things. fast forward to now, over christmas i unpacked the crate it was all boxed up in, and decided to setup and finally try to finish.
Im using the shape i had cutout and made templates for at the beginning, everyday ski, 105mm waist aprox 18m radius, 184cm long, rocker tip and tail. the cores are douglas fir (harvested off our local ski hill!) and maple. The plan is to vacuum bag for a press as i already had a suitable unit from doing A/C repair. Basic sandwich construction, 22oz fiberglass top and bottom of the core, no spacers or sidewalls, and a clear topsheet. The plan is to vacuum to teh sheet of 14ga steel, pressing the sandwich of the ski together, and then use spacers clamped underneath to form camber and the tip and tail rise. the steel seems sturdy enough to form a nice smooth radius when clamped against a block.

[skibumben]

spent some time in the shop last night getting ready to press. plumbing my vacuum pump to work for pressing skis. does anybody use a resin trap on the line leaving the bag? or is epoxy getting pulled up and throught the pump usually a non issue?

[TimW]

Definitely use a resin trap. If you really want to do without it, make sure to use a long hose to at least get some buffer.

It also serves as a vacuum vessel. I normally shutdown my pump(but you need to be absolutely airtight for that.

[skibumben]

tried a test press last night using a scraps of base, core and topsheet.
was havving trouble pulling a hard vacuum. wondering what people typically expect for vacuum levels when bagging? when doing a/c work i usually get 25-30 in/hg. i seem to max out a 18 in/hg last night.

[skibumben]

despite the problems with my vacuum bag, my test piece turned out looking like a section of ski. kindof exciting.

[TimW]

You should be leak tight, so if your pump can do 30", you should get 30". If you have a leak you have air flowing, and that may go through your laminate, messing it up. Sometimes you keep having a small leak, but any leakage is tricky.

Are you using tacky tape? I see a lot of packing tape. It is almost impossible to a proper seal with packing tape.

[skibumben]

yeah, i was being a cheapskate. i have a roll of the right stuff coming. so lets hope thats the issue!

[sammer]

I'm at around 3000' elevation and have a very similar vac pump (old robinair).
I pull around 24"hg even with a small leak thru the glue joints on my press frame.
You will do better once you get some proper sealing tape and a decent film.
I used 6mil vapour barrier for my first few builds with the yellow sealing "tape". Worked good, but had to work out how to pleat the corners as, it didn't have the stretch to get around my tip and tail molds.

Your laminate looks pretty dry. Use a bit more epoxy and a J-roller to squeeze out the excess once it is in the bag, under vacuum.
You'll need to have a place to push the excess to.
Your film will try to keep it all trapped if you don't put in some type of exit where the film caps over the edge of the laminate.

sam