Fabric Presses

[TheDominator]

Hey guys, I'm a new member to skibuilders. I've wanted to build my own skis since I was in high school and I finally have a bit of money lying around to do it with. I'm a student at the UW and I don't have a lot of money so I'm trying to do this the most cost effective way. I was leaning towards a cordura press because it seems to have worked for a fair amount of people on here. I was wondering first of all where I could obtain cordura(preferably for cheap!) and also if anyone had tried using kevlar? Kevlar has a high tensile strength and although it is not as tear resistant as cordura, I think it might work. Just looking for suggestions/comments/ideas. Thanks

[twizzstyle]

Do some searching, there are a million threads on this, and some very recent ones. Here's one!

http://www.skibuilders.com/phpBB2/viewtopic.php?t=2553

Kevlar would probably work great too (not tear resistant?? Kevlar is probably the most tear resistant thing ever... I hate working with the stuff, it's a bitch to cut). The only hard part would be sewing it together so it doesn't just unravel. If you could find a biax woven sleeve large enough to go around the press, you'd be set... but I doubt something like that exists and the cost would be astronomical.

What are you studying at UW? I graduated from there in 2006, from the Aeronautical Engineering department. I live in Kenmore now.

Welcome to the site/hobby!

[TheDominator]

I'm in the materials science and engineering department.

I was doing some further research and I found a good explanation of the differences between cordura and kevlar. Its from a company that manufactures motorcycle gear. Anyway I guess I kind of answered my own question, and I'm still poking around in threads on fabric presses. It looks like cordura might be a better choice because of the elasticity, but I have easy access to a supply of kevlar through school, so i might go that route anyway. I'd love to hear from anyone who has attempted that, as I haven't found any threads where anyone used kevlar in place of cordura.

The stitching will be the worst part about using the kevlar, although I can't imagine its any different with cordura. It might not be so bad if I were to use a smaller thread kevlar. Like a 3mil thread.

"THE STRAIGHT STORY ON KEVLAR
or Kevlar vs. Real-World Abrasions
Aero Design pioneered abrasion resistant motorcycle riders suits made of advanced technology fabrics. We continue to be the world leader in this field so we're often asked why we choose Cordura nylon, Ballistic Nylon, and Gore Tex laminates for our Roadcrafter and Darien garments. Why not Kevlar?

We'd heard good things about Kevlar's qualities when we started our work, but back then Kevlar simply wasn't available in a useable form, so we chose the most effective materials available. Our rigorous original testing and subsequent experience (as well as our customers') has shown Cordura Nylon's abrasion resistance is not merely sufficient, but it has far surpassed riders' needs and expectations.* We've examined and repaired hundreds of crashed suits, some tested at over 100 mph. Visit our shop sometime and we'll show you actual crash tested suits and our abrasion testing materials and apparatus. Today Kevlar, manufactured in a useable form only by Schoeller Textile Company in Switzerland, and used by other makers of protective riders clothing, is readily available.

We still choose Cordura, not Kevlar. Here's why:
Its advantages don't make up for it's disadvantages. In pure, undiluted form, Kevlar is lighter than Nylon and has greater tensile strength than Nylon. It won't melt like Nylon after touching a hot muffler (or from the friction generated heat of a high speed slide on hot pavement). Unfortunately, it's expensive and difficult to work with, which limits design and construction possibilities. Believe it or not, pure Kevlar fabric actually is much less abrasion resistant than Cordura Nylon. This quality is not important for bulletproof vests. Kevlar fibers have far less elasticity than Cordura Nylon fibers, a crucial handicap. In a crash, even the smoothest pavements have a rough aggregate surface that causes abrasive pulling. Nylon's stretchy fibers will elongate, ride over the surface irregularities, then snap back into the weave (like a tree bending in a strong wind), but Kevlar fibers quickly reach their tensile limit and snap.

To solve these problems, manufacturers blend Kevlar with Lycra and Nylon. In this blend, "Kevlar" is only about one third actual Kevlar. This creates problems: because of the additional Nylon and Lycra, much of its slight weight advantage over Cordura is lost. It also loses its fire-retardant qualities. The blended Kevlar fabric will burn or melt (just like Nylon) when it comes in contact with a flame, hot component, or high frictional heat.

Some Kevlar suits may provide good crash performance because they are specifically designed for competitive roadracing. Roadcrafter suits aren't designed for sanctioned roadracing, but fortunately theyOre designed for everything else, including abrasion resistance at highway speeds. We've tested (and will continue to test) Cordura nylon against the alternatives. Its superior comfort, easy workability and excellent abrasion resistance make it our choice for quality, versatile, high performance rider's clothing. You've got a choice between the Roadcrafter and its proven record of outstanding abrasion performance, and something that costs more and delivers less. Guess what we recommend."

[MontuckyMadman]

Unbacked and backed cordura can be found on ebay, at rockywoods in CO and the like. Its not cheap but the good stuff never is.

Its nowhere near the cost of kevlar, OMG!

I double up 1000D on my press designs and sew a parachute style box non overlapping stitch, while I overlap the material by at least 2 inches in the meeting area.

I can build them or you can. My scrap supply is getting lower with all the recent inquiries.
My cost is nominal, if you know your press dims and I have material I can make a press for you, let me know.

[TheDominator]

Cool Montucky. I haven't designed the press itself yet, so no dimensions. I'm going to draw it up this weekend/next week in CAD.

Kevlar is expensive, but we have a bunch of it laying around at school that was donated by some company and no one uses it for anything. So I have a potentially free supply! I gotta go check it out and see if its actually usable though, because some of the rolls we have are beat to hell. But I'll let you know if I need some cordura, thanks for the offer.

I'm also thinking of using kevlar because it seems like no one has tried it before, might be a worthwhile experiment. If it doesn't work I'll use cordura. I'll probably post my design and see what you guys think before I start building though.

[webboy]

I'm in the materials science and engineering department.

I second the welcome! No, seriously, welcome.

[webboy]

My scrap supply is getting lower with all the recent inquiries.

I was wondering when that would happen.

Funny idea- your generosity is at risk of going on back-order!

[MontuckyMadman]

Ill trade ya kevlar for cordura and eat the shipping?

[TheDominator]

Yeah that could be a possibility, Montucky. but like I said I gotta check what we have in the lab. I'll let you know.