Ski Builders Forum

I expect my first ever ski to be a failure, but i hope some critical suggestions from the forum will prevent a complete disaster, particularly in profile and cloth weight. Thank you in advance.

Thanks to various boat building projects i already have plenty of carbon, resin and ash. The only costs will be the bases, edges (?topsheet) and consumables. And my time.

Use, touring probably mounted with dynafits, europe / norway occasionally near a piste and using the occasional lifts.

Shape. I wanted something like my 2005 wailer 105 (flex2), but with more sidecut underfoot and a longer rise in tip and tail (not twin tip as for touring). Resulting shape is not dissimilar from a dps wailer 99. (125/102/115) 350mm tip rise to 70mm, 200mm tail rise to 40mm, 5mm camber underfoot. 178cm total length

Stiffness. I am 1m90 and 66kg - tricky to find skis for this shape, but i hope to build additional skis for a 1m80 and 75kg and a 1m75 and 55kg. All are very good skiers. Hopefully the first ski will suit one of these and the others can be adjusted accordingly!

Construction:
base and edges
uc200 (200gsm unidirectional carbon at 0deg) (equivalent to 6oz i think). xc405 (405g/sm 45/45 biaxial carbon) (12oz equivalent)
ash core, vertically laminated - heavy i know, but i had some. i plan to make it thin 2mm-10mm-2mm. scrap carbon tip and tail spacers. bare sidewalls
xc405. uc200.
? a top layer of plain weave 200gsm carbon.
I plan to resin infuse so am not sure how this will work with a topsheet.

I am vacuum resin infusing as i have the kit and don't have a compressor or fire hose, and my mould will be correspondingly simpler.

If, once profiled, the cores come out too heavy, i am considering inseting some corecell M80 (san foam) that i have plenty of.
If i leave the cores solid ash, i wonder how necessary the 0deg carbon is.

It will be fun trying in any case.

the hoff wrote:I plan to resin infuse so am not sure how this will work with a topsheet.

Will it work with a base? Please let me know your results...

Cheers, Christoph

Sounds like you've got a good plan in mind, so I wouldn't assume failure. Sounds like a great ski to me!

I have two questions - you said scrap carbon tip spacers? What kind of scrap carbon? Just some fabric? That will give you really thin tips, which I guess is ok... just not normal. If it's already cured thicker stuff, it's not going to bend to the tip shape.

Second - why are you doing infusion, versus just a normal wet layup and vacuum bagging? If that's what you're used to from boat building, then it's probably a good idea, it's just not something people normally do when making skis.

I think the infusion will flood under the base and tips and cause problems.
A solid ash core and those carbon weights will make a stiff ski in my opinion but at those dims you could be OK.

I'm unsure if infusion will work with a base, but am going to run some small tests with the laminate stack with small small resin channels cut in either core or base. The base should stay flat because of the mould, a top sheet will probably show the cuts - fine if i make them a neat pattern.

Infusion should have a much lower void content than wet layup - comparable to what you achieve with your presses. I assume voids are the main cause of delamination/failure.

Tip spacers will just be 2000g thickness of carbon off-cuts, so approx 2mm once consolidated. Tacked together with some light spray adhesive so i can cut to shape. I may get some plastic though...

MontuckyMadman wrote:I think the infusion will flood under the base and tips and cause problems.
A solid ash core and those carbon weights will make a stiff ski in my opinion but at those dims you could be OK.

I think you might be right about under the base, but will see if double sided tape keeps the resin out.

I could reduce the core thickness further, or reduce the amount of longitudinal carbon. Not many carbon skis on the forum to guide me, so thanks for the input.

The only way to know for sure is to build the things, I say go for it as-designed now and see what you get. I'm actually curious how the infusion will work (I use a pneumatic press so I'd never do it, but sounds interesting nevertheless). Sounds like you know that process pretty well so if it works out well it might be a good thing for the vacuum baggers on the forum to consider.