insomnia skis 2011/2012

[a.badner]

Wanted to start a new thread...

Here is my last prototype for my use. (all my prototypes are used for summer skiing on astroturf )

Specs:
-Poly Urethane Sidewalls (Therefore there is no vds in the ski)
-Material Topsheet
-Base + edge, Biaxial 12oz. glass, 3/4 Length Uni Glass, 1/2 Length Uni glass, 1/4 Length Uni Glass, Core, Uni Glass, , 1/4 Length Uni Glass, Material Graphics, 8oz. Biaxial glass
- Core Specs: 3mm - 9mm - 3mm (Only tapered for tip bending otherwise flat, thus the need for Pyramidal Uni glass)
- 900 g (SUPER LIGHT SKI, and its NOT a noodle)
- P-tex tip spacers
- 110-88-105
- 3/4 Wrap

Im using a new epoxy. the revchem was much too heavy.

Its actually a surfboard resin, so the bondability with and poly plastic is much much better. This epoxy is much less brittle.

(Im done with Shipping price prices from the states. too ridiculous. Im buying from vendors for much less now)

PLASTIC WORLD'S OWN SURF BOARD RESIN

A UV-resistant high-modulus epoxy, it is almost water-white and dries to a clear, glossy, blush free surface. It is formulated for builiding & fixing sail & surf boards over polystyrene cores. It can also be used for coating and laminating even over polyester and gelcoat without a gelcoat.

Mix Ratio: 2:1 Color: Water White Pot Life 40 min Cure Time: 36hrs Coverage: 3.6sqm/L

Its here: http://www.plasticworld.ca/default.asp?pid=53

Pretty much NO edge fall!!!!! Bases Decently flat!
Though the core did miss align a little while pressing, nothing too serious. Though i found a air bubble in PUR side walls after cutting out the the skis, its only about a 1mm deep, so pretty precise, but im still angry about it :@ haha

For Next time: Less PUR ( its gone too far into the skis ) and a different bases material. possibly the colored electras i bought earlier. :P

Pics? :P yeaaaaa Bad ones tho. the green is actually more of a denim color :S

FULL SKI (the green looks really dark, but it isnt at all)



PUR side walls in the light, WAAY too deep into the ski



nose



PUR, nice rubber color



STUPID! AIR! BUBBLE! haha too bad



Base Clear 2001 durasurf.



That's for you twizz, pics or it never happened.

CODA???? Do they give good shipping rates?

EDIT: I put on A (one) shoe just for the pictures, yet, i miraculously managed to get the bare foot in there as well ... ugh

[twizzstyle]

I'm completely lost by the second picture, what are we looking at exactly?

Did you route the sidewalls after cutting off the flashing? It's hard to see what the finish of the sidewalls looks like in the dark.

Cool idea on the stacking of glass.

[doughboyshredder]

ski still with flash on it backlit to show the urethane sidewalls.

How did you do the urethane sidewalls? What material did you use? Pour them yourself? Did you use anything special to help bond the urethane, as it is not supposed to bond well with epoxy, but there is a special catalyst you can use.

[a.badner]

Twizz: DBS has got it , and yes, i have gone back to routing the bloody sidewalls. My past self was too impatient with a router. although there is no bevel. Machining the urethane KILLS HSS. From what ive learned at my day job, 90% of commercial carbide isnt actual carbide. carbide only comes in the smallest amounts and there is no way to infuse it with a steel. REAL carbide only comes on inserts for indexable endmills or face mills or drills. Ill try to get better pictures for you. But that may or may not be impeded with my laziness. after routing i did a sanding with 120 grit, so its nic(sh)e and s(h)moooooooth.

DBS: As I noticed, pretty much anything can bond with epoxy if roughened and flamed. (To an extent) Im using a casting resin from a local distributor. its extremely hard. I think its something similar to this...? ( http://www.mcmaster.com/#8644k58/=diuku3 ) when i first casted it, i thought it was a epoxy. but only after touching it and sanding it it felt more like a rubber. Do be careful if flame treating the urethane. Its turns black within a few seconds with flame over it.

EDIT: Oh and dont be discouraged while sanding the urethane, it may look like there is NO abrasion happening what soever, but once flaming you can see almost like little white hairs coming off of the urethane.

I used the moating method. Template, routed out a channel in the wood, then poured the urethane in. I have a core being casted with sidewalls right now actually. i could take pics later is your please.

After that, i profile with a planer, then belt sand the entire core with a 50 grit belt. flame the urethane.

havent had problems with it yet... i would like to elaborate on the YET part. i could be doing something completely wrong, but from my understanding of chemistry, by flaming and treating, were not chemically changing the polarity of the surface atoms. Its a mechanical treatment. When the air bubble out of plastic (or urethan in this case) it creates a larger surface area for the bonding to happen. BUT, i am a teenager and i am much too lazy to actually read about the science of flame treating on my own time. If a chemist would like to explain the chemical changes during an "oxidizing" flame treat, please do so


HOPE THAT CLARIFIES SOME THINGS!

BTW, press is fine........................................................................ still.


and for topsheets? CODA or sb mat. ???? Do they give good shipping rates?

[twizzstyle]

You need to email Coda and snowboard materials for shipping quotes, we can't help you with that.

What's the purpose of the 8oz biax on top?

[a.badner]

It's to protect the entire ski and it gives a nice lustre finish I'll get better pics asap

[Dr. Delam]

Am I seeing more tail than tip? They look like they are mounted backwards.

[MontuckyMadman]

that sounds like a polyester resin you are using. That would be bad.
No need to sand your cores after planing, the planer surface is best for wood bonding.

[a.badner]

DD: nope. Boot center @ dead centre of the of the ski. I think it just looks like that cause the pivot/fks need less mounting space on the heel piece. It looks weird but it's definatley at dead centre.

MM: no it's epoxy. My dads company uses polyester resin to coat the copper wires on their alternators. I know what polyester is. It much too brittle for ski making. It's like glass :P and I disagree. When I use a 50 grit ceramic (the blue ones) belt for the sanding the cores, it looks like the abraded side of the ptex. Furthermore. I don't sand the cores to sand the wood, I sand them for the PUR. yea yea, PUR doesn't abrade, but it really does. The tests I ran with the PUR sidewalls definatley showed a better bond with sanding with 50 grit and flaming.

[MontuckyMadman]

data shows 80 -100 grit best for abrading your disagreements are not backed in fact.

[a.badner]

Show me this data!!!

i know what worked best for me, and im going to stick with that.

Im not going to start this again. Go troll somewhere else.

EDIT: BTW, there are much too many types PUR for there to be a consistent best result. fact is im using one of the harder Poly urethane resins and 100 doesnt even change the bonding where the 50 grit did.

[Richuk]

He means this viewtopic.php?t=2531&postdays=0&postorder=asc&start=195 and the pdf.

I think you are right - do your own tests. Amazed by your progress, looks like you have taken the ski apart and re-designed from scratch.

9mm and no noodle is impressive!

Have you looked at carbon tows - if you have the time, you could probably wrap/plait the core in some creative way? Alt, you might also consider sewing it into the fibreglass - if you consider straight lengths. Maybe notching the core @ tips and knoting the carbon tow would ensure it remains straight. Genius - pre-tensioned carbon tows! LOL

[a.badner]

good idea, but i have too much uni glass.

i actually came across the 9mm + tapering lengths of uni flex pattern by accident. i remember posting about a horizontal lamination skateboard style core. then i thought about how much lighter fiberglass is. then i started a lay up (without base or sidewalls) just to see how it would work. The last four pairs i made all ended up the same way

[MontuckyMadman]

sanding the wood creates hairs that dont bond well and clogs the surface pores of the wood.
A planed surface is best for bonding wood, open pores and good adhesion with a mechanical bond.
the pu you are using and plastics are different and should be dyne tested or water/sheet tested.
It still shows that creating an over abraded surface in plastics and wood will create a hairy and thus a shear-able surface.
Again just a few tests and you know everything. grow up.

[a.badner]