fibreglass, how much?

[skimakermark]

Hi guys, newbie, very thankful for the excellent site, loads of info that has helped a bunch. starting some skis in australia out of home laminated paulonia, succesful so far. some questions on some things im having trouble working out....
how many layers of glass do you need to use? ive worked on surfboards in the past, but dont really know how many layers of this 22 oz stuff one should use on skis? several sheets, just the one? i dont mean in terms of base material-composite-core-composite-topsheet, but literally, in each fibreglass layer, how thick should the glass be?
the tip tail spacer ive just boughty through the site, does that need flame treatment or can it be used in the layup immediately?
if i put rubber strips down on the base, does it go on the edges or across the entire ski? if only on the edges, will this create a gap in the centre of the ski, ie. the core will sit on these rubber edges, with a gap betweeen them...or will the epoxy and glass fill this void farily effectively?
again, thanks for the great site, it has helped a bunch so far. wish me luck.
mark

[jono]

Hi skimakermark,
In general, when a lay up list says "22oz fiberglass" it means 1 layer of that type of fiberglass each time it is listed. Most of the time builders use the same amount of glass on either side of the core. I'm not sure how thick the fiberglass layers are after pressing but it is way less than you would think.
If you are using the vds type of rubber over the edges it is so thin that it will not leave any noticeable gap. You can use this vds material on the edges or anywhere you want to have a flexible layer to absorb shear forces that can lead to delamination.
The tip spacer material on this website is already treated to bond with epoxy on both sides. You don't need to flame treat it.
If you are worried about gaps you should pay attention to the metal flanges that sit on top of the base material. It is wise to rout out the parts of your cores that will set on the edge flanges in order to have everything fit together with no gaps.
Good luck.

[twizzstyle]

Yep, very generally speaking for most people 1 layer of ~20oz fiberglass (22 is great) on top and 1 layer on bottom is good. 2 layers on either side would be overkill and just make the ski heavier (because of the additional glass and additional resin). I am of the opinion that its best to just do single layers of fiberglass (top and bottom, two layers total), then use core thickness to adjust the stiffness of the ski rather than amount of fiberglass.

One layer of ~20oz triax fiberglass when pressed/cured will be maybe 0.5mm thick at most.

The fiberglass will fill up the gap left by the VDS only over the edges, no need to account for it as the VDS is very thin.

[skimakermark]

thanks guys, this all makes sense, with surfboards its more often a few layers of lightweight glass, so just thought id check. waiting on my materials to arrive, then on a hot melbourne day (110+ degrees) will do the layup and pressing. lacking a heated press, will this temperature help at all? seems theres some debate about how hot presses need to be, but i dont mind how long the pressing takes, and figured that, either way, hotter is better...thanks agian for the help, this site has stacks of info.

[doughboyshredder]

with surfboards its more often a few layers of lightweight glass

You can do the same thing with skis or snowboards. For example a person could use one sheet of 8 oz double bias, and one sheet of 12 oz unidirectional in lieu of one sheet of 20 oz triax. Building layers allows you to fine tune your reinforcement a little bit more. Another layup could be 6 oz double bias and 14 oz biax for a 20 oz quadraxial layup.

You could also use multiple sheets of a lighter weave.

[King_of_the_Hill]

Wouldn't wait for a hot day, the epoxy could accelerate ieg harden before you get the bag closed! Maybe thinker with the AC keep it cool during lay-up get it hot when the bag is closed.