Hemp Question???
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Hemp Question???
Hello all, I am working on a pair of skis and I want to try to use Hemp instead of the 22 oz. tri-ax fiberglass I have used in the past. Just wondering what weight Hemp would be close to the same, I have found 19 oz. and also 22 oz. Hemp. Any suggestions would be great, Thanks....KT
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doughboyshredder
- Posts: 1354
- Joined: Mon Sep 17, 2007 7:37 pm
could you post a link to the supplier? I have been looking for comparable strength testing data, but can't find any.
for suppliers this is all I have found http://www.hemptraders.com/index.php?cPath=21_39
for suppliers this is all I have found http://www.hemptraders.com/index.php?cPath=21_39
How are the hemp fibers oriented? Triaxial fiberglass is, well, triaxial. There are fibers running along the length of the ski (0 degrees), as well as +/- 45 degrees on either side of that.
If the hemp is just a typical woven fabric (I would guess 0/90 orientation), then you aren't really going to get any torsional stiffness.
And if the hemp weighs 22 oz/sq. yard then it is equivalent (in weight, not mechanical properties) to 22 oz triax.
If the hemp is just a typical woven fabric (I would guess 0/90 orientation), then you aren't really going to get any torsional stiffness.
And if the hemp weighs 22 oz/sq. yard then it is equivalent (in weight, not mechanical properties) to 22 oz triax.
Adding to that, I'm sure the final product will be MUCH heavier as it will absorb much more resin vs. fiberglass.
Quick comparison:
From Matweb, generic E-Glass - Ultimate Tensile: 3448 MPa, E: 72 GPa
From http://www.springerlink.com/content/m6w ... pdf?page=1 - Sun Hemp - Ultimate(?) Tensile: 389 MPa, E: 35 GPa
So it's going to take quite a bit more hemp fiber to match glass.
Quick comparison:
From Matweb, generic E-Glass - Ultimate Tensile: 3448 MPa, E: 72 GPa
From http://www.springerlink.com/content/m6w ... pdf?page=1 - Sun Hemp - Ultimate(?) Tensile: 389 MPa, E: 35 GPa
So it's going to take quite a bit more hemp fiber to match glass.
I've been using 12oz hemp in two layers, one straight up and one at 45 to replace the Uni and 45 biax I would otherwise use (don't have easy access to triax here)
I have taken them to hell and back and they are still in one piece. I skied them back in November when we had 3 foot of fresh and nothing under it, I've skied them in the trees when the lifts first opened and there was dust on dirt. And on the biggest runs on the Midi and off the top of Courmayeur
Before I made any hemp skis I made a bunch of test panels, about 10cm by 80cm and tapered from 2mm to 8mm or something. I clad them in different weaves of glass and hemp. I then flex and torque tested them. I found a weave that worked much like the biax glass worked.
If you do an absolute tensile test (sor of thing you do with climbing gear) hemp doesn't hold a candle to glass, but for the performance you need in a ski it works
Remember all the rope and sails of bots were hemp. Lots of the WW2 fighters and bombers were hemp canvas over wood!
I have taken them to hell and back and they are still in one piece. I skied them back in November when we had 3 foot of fresh and nothing under it, I've skied them in the trees when the lifts first opened and there was dust on dirt. And on the biggest runs on the Midi and off the top of Courmayeur
Before I made any hemp skis I made a bunch of test panels, about 10cm by 80cm and tapered from 2mm to 8mm or something. I clad them in different weaves of glass and hemp. I then flex and torque tested them. I found a weave that worked much like the biax glass worked.
If you do an absolute tensile test (sor of thing you do with climbing gear) hemp doesn't hold a candle to glass, but for the performance you need in a ski it works
Remember all the rope and sails of bots were hemp. Lots of the WW2 fighters and bombers were hemp canvas over wood!
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sustainableplay.com
- Posts: 2
- Joined: Mon Mar 22, 2010 1:19 pm
I just spoke with Laurent @ Hemp Traders, and told him what telehead and I are trying to do. He reported that several years back a snowboard maker purchased 4.6 oz 100% fine hemp linen for the same app (I asked who, and he didn't remember). Based on weight alone, he recommended either the 4.6 or 5.8 oz linen.
I asked him whether he's starting to see more demand for industrial applications, and he told me that most manufacturers are purchasing raw fiber. I asked whether a combination of linen with fiber might work, and he thought so. He recommended F-S1, uncombed short length fiber. He surmised it would be relatively easy to lay out in strands, perhaps under the linen. Just another wrinkle.
But based on Idris' experience, I'd be inclined to go with the 12 oz canvas. Maybe we'll try both.
P.S. He imports his fabric from China, so from a carbon footprint standpoint, there are significant externalities. His fiber comes from Canada.
I asked him whether he's starting to see more demand for industrial applications, and he told me that most manufacturers are purchasing raw fiber. I asked whether a combination of linen with fiber might work, and he thought so. He recommended F-S1, uncombed short length fiber. He surmised it would be relatively easy to lay out in strands, perhaps under the linen. Just another wrinkle.
But based on Idris' experience, I'd be inclined to go with the 12 oz canvas. Maybe we'll try both.
P.S. He imports his fabric from China, so from a carbon footprint standpoint, there are significant externalities. His fiber comes from Canada.
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King_of_the_Hill
- Posts: 29
- Joined: Mon Oct 01, 2007 11:48 pm
- Location: Netherlands
- Contact:
I use www.hempshop.co.uk but there are manyKing_of_the_Hill wrote:I've been looking for orientated hemp for quite a while without any proper result. Im working on the combination of hemp with PE matrix.
Anybody got an idea for euro suppliers?
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sustainableplay.com
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- Joined: Mon Mar 22, 2010 1:19 pm
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ironmonkey
- Posts: 10
- Joined: Sun Mar 28, 2010 10:28 pm
hemp cloth for layup
check out this website greenlightsurfingsupply dot com
it's a surfboard shaper oriented site but they have a special hemp cloth they use in laying up surfboards, completely foregoing fiberglass cloth altogether. they claim it has superior rebound properties when layed up stretched/under tension. than the industry standard(surf) 4 oz cloth.
it's a surfboard shaper oriented site but they have a special hemp cloth they use in laying up surfboards, completely foregoing fiberglass cloth altogether. they claim it has superior rebound properties when layed up stretched/under tension. than the industry standard(surf) 4 oz cloth.