WEIGHT REDUCTION

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wingworks
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WEIGHT REDUCTION

Post by wingworks »

have a great flexing poplar core 185cm powder ski -----need to keep the great flex but loose some weight 11 lbs a pair no bindings!
151/126/132mm and 12 mm core under foot
using22 oz triax and 10 tow carbon top and bottom

has any one tried to replace the triax with 6 oz plane weave carbon applied at 45 deg to the ski (to yield a 3 oz 45 layer in both directions for torsion) and one 7 oz uni fiberglass for the tension (similar to the triax)
NinetyFour
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Post by NinetyFour »

Just curious as to what PSI/how confined your bladder is pressing at or if you're vac bagging? Are you getting a proper squeeze out when making skis? They do seem to be on the heavy side of things @ 11lbs for the pair, but not completely unusual for a ski that big.
ProbsMagobs
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Post by ProbsMagobs »

How about this? Using it to replace your fiberglass and keeping the uni carbon tape should keep things lighter and keep similar flex. I'm no expert so you should get another opinion on this
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vinman
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Post by vinman »

That's a pretty big ski. It may never be in the super light category.

What type of tip spacer to you use. full plastic vs. interlock style might get you a few grams.

Do you rabbet your sidewalls. This makes a flatter ski and saves some weight.

What kind of sidewalls? UHMWPE is heavy. But probably adds some dampening vs wood or bamboo sidewalls. You can bevel your sidewalls a little more to cut a little weight. For a wood sidewall you could probably go up to like 30deg or so, especially on a ski that big.

What kind of top sheet are you using? veneer weight vs. plastic weight. The veneer is lighter but requires more resin and some varnishing to look nice. probably a wash in terms of which is lighter.

how much epoxy are you mixing.

what type of press and at what pressure are you pressing?

Are you trying for a stiff ski? The reason I ask this one is that you might be able to go with a slightly thinner core if you used some harder woods thrown in there, especially under the binding screws. Poplar is OK but I personally don't put poplar where there will be screws. I like something harder to beef up screw retention.

You might get away with 19oz glass plus your carbon tow also. Vectorply 19 oz glass has the 45s weighing the same as the 22 oz glass. Only the longitudinal fibers are lighter. So again you might save a couple oz here and still use some carbon selectively to beef up your flex.

All carbon is another way to go. something like 8 oz triax if you can find it.

Or some lighter carbon biax with a some lighter weight triax glass. I have no idea how this would work but some guys do it. It might weigh less but I'm not sure.
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wingworks
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weight reduction

Post by wingworks »

since last post we made two more pairs -using vacuum bag in autoclave at 80 psi---- at 90 psi the fibers start to look too dry . we use wood all the way to tip with all cap construction and no top sheet ,i guess we are in the ballpark as my buddy's--black diamond megawatts are 0.25 lbs lighter /pair

the next ski we maid had same layup but used laminated core of alternating 5/16"wide poplar and divinycell foam no topsheet --saved 2 lbs/pair !

next pair we used ---vertical grain aircraft spar grade sitka spruce(16 grains/inch- solid one board core -no Lamination's --hard to find but-way less work came out 1.5 lbs lighter than first pair

ps
side by side 12-15"powder the homemade skis had more bounce an decelerated less in the turns than the soft megawatts for my 195 lbs

ordered the carbon for next set
prospectsnow
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Post by prospectsnow »

Laminate some prepreg carbon between the wood core strips and plane that beast down Goode style.

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vinman
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Post by vinman »

^^ I've thought about that but I wonder what cured carbon would do to planer blades....
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Huck Pitueee
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Post by Huck Pitueee »

Next time you select core wood check through the stack for the lightest pieces. There can be large variations in density from plank to plank.
Upper Left Coast
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powder fattys

Post by Upper Left Coast »

sounds like a reasonable weight for such a big ski, i got excited on my first couple pairs with full length bamboo and no sidewalls because they were quite light. now we use a full wrap liquid polyurethane rubber sidewall and it adds a few ounces but i think it's worth it for durability and dampening especially on a rockered ski. We found some good spruce and i can't wait to use it.
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