I've been jonsing for something better than cathedral-on-choke-chain poi for a while. I've come up with a design for some all kevlar poi that I like, where the head is 3/4" or 1" kevlar rope (haven't decided yet, leaning towards 1") done into a simple circle macramé knot. The body would be 1/2" rope that runs through the space in the middle of the head (done while braiding the head) with an oyster knot on both sides of the head to keep it in place.
The handle would be the same thing done with 1/4" cotton rope (Which would be cheap and dyeable, though kevlar may be better incase the handle comes in contact with the head.)
I made a cotton prototype rather like it, especially for tosses. Before I dropped some $40 into kevlar, though, I figured I'd get some feedback on it. Is kevlar rope going to be able to hold up in tension? I like that the rope isn't permanently attached to the head, as it would at least theoretically allow for the body to be replaced. If it were to break it would seem like it would happen at the part right above the head that gets exposed to the most flame, but would it be better to err on the side of caution and sew the body into the head?
Any thoughts anyone has would be greatly appreciated, I really value the wisdom available on this board (<3 the internets).
The handle would be the same thing done with 1/4" cotton rope (Which would be cheap and dyeable, though kevlar may be better incase the handle comes in contact with the head.)
I made a cotton prototype rather like it, especially for tosses. Before I dropped some $40 into kevlar, though, I figured I'd get some feedback on it. Is kevlar rope going to be able to hold up in tension? I like that the rope isn't permanently attached to the head, as it would at least theoretically allow for the body to be replaced. If it were to break it would seem like it would happen at the part right above the head that gets exposed to the most flame, but would it be better to err on the side of caution and sew the body into the head?
Any thoughts anyone has would be greatly appreciated, I really value the wisdom available on this board (<3 the internets).
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Re: Poi design questions
Sun, January 20, 2008 - 12:13 PMThe kevlar that is being used to replace the chains would hold up very well, though it depends on how often you spin and how hard you spin (fast spinning, lots of wraps or shots will be worse). You will see it start to wear out, it would fail as abruptly as ball, but it will be more expensive to replace.
So it should work, but it will not be very durable. -
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Re: Poi design questions
Sun, January 20, 2008 - 1:26 PMI don't really see how it would fail as abruptly as ball; you can see rope wear down. The only hidden part is inside of the head, and I believe the part just above the head would fail first. -
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Re: Poi design questions
Sun, January 20, 2008 - 2:18 PMYeah, looks like I left of the n't on my would. You will see it wear, -unlike- ball.
I though about running cable through the middle of rope at one point, but never got around to it.
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Re: Poi design questions
Sun, January 20, 2008 - 2:47 PMI've made a couple of prototypes along these lines, although neither have a lot of burn-time in them. Mine actually are made entirely out of a single length of 3/8" kevlar rope, which serves as a monkey-fist head, the "chain" and a wrist-loop handle.
My guess is that the failure point would be on the rope just above the wick. -
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Re: Poi design questions
Mon, January 21, 2008 - 1:02 PMI agree. The section of wick with no fuel WILL char quickly, as while Kevlar and fiber are very heat resistant, they're not entirely fireproof. The fuel is what keeps it from disintegrating (that's why they say don't let your wicks smolder out), so I would think they would have a pretty high rate of failure. Only one way to find out though, I say go for it. If they don't work you can always recycle the Kevlar! -
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Re: Poi design questions
Mon, January 21, 2008 - 3:07 PMActually, grim, the fuel can help to keeps your wicks from disintegrating, but really it's the heat. Most wicks don't produce enough of an aeroflow near one point to notice it, but I've watched snakes and death stars carefully. Both are capable of producing a full burn heat that is focused on a specific part of the wicking. In the case of the snakes, the flow over the monkeyfist is lovely and round, interrupted only by the connection point. When that point is kevlar, the 1" area immediately above the wick takes damage. If kevlar deterioration were all about the fuel, then we'd see much more deterioration at the very top of the snake (where centrifugal force is drawing the fuel from), or at the very bottom of the monkeyfist (where the greatest speed and thus the greatest heat happens).
I personally believe that the smoldering myth is a holdover from when people regularly used terry cloth wicks. In the case of cotton, a smoldering wick can get completely eaten in a couple of hours, and a good ember dropped in white gas could cause a bucket burn. Kevlar does not self propagate embers like cotton does, Though a hidden ember can cause the same problems with dipping. Thus the resiliency of the myth.
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Re: Poi design questions
Tue, January 22, 2008 - 12:09 PMI made a prototype set out of cotton rope and enjoy them immensely. I think some metal tape around the problem spot above the head will make it work. We'll see, gotta get a paycheck before I can order the Kevlar. -
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Re: Poi design questions
Tue, January 22, 2008 - 5:51 PMMetal tape might make friction wear a problem...
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Re: Poi design questions
Wed, January 30, 2008 - 10:25 PMI'm excited for your pay check. At least you get to try something cool.
I'm rigging colapsable fans to some poi chains similar to a rope,fan, dart. Sprung loaded to open when tripped. -
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Re: Poi design questions
Tue, February 5, 2008 - 11:31 AMOkeee dokey. Wasn't gonna reply again, but it must be done. I feel like debating.
When spinning snakes, you don't see damage to the uppermost part *because* the fuel drains quickly, and blows out quickly, not leaving much time for heat damage. The connection point however is subject to the hottest point of the flame as the head continues to burn, and without the layer of liquid to protect it the -heat- (duh) will char the rope. That's pretty obvious.
As for letting your wicks burn out, it's not a myth. As the fuel burns off and starts to draw from the center "reserves", the outer layer of the wicking is exposed to hotter parts of the flame with no liquid protection, and will char faster than if they are blown or put out a tad early. I have had many a set of poi lose their outermost edges and seams to this effect, and start to fray with minimal abrasion.
Let us know how your new toys turn out! -
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Re: Poi design questions
Tue, February 5, 2008 - 12:34 PMOkay, this is getting silly.
The very surface of your wick should not have liquid on it when you light up. If it does, you will be throwing gobbets of liquid around as you spin. As for the liquid coating idea, take your fuel and paint a thin layer on the ground then light it. When the ground goes out, your wicks are dry (on the surface). With white gas this takes about 10 seconds. [Evidence: back to the future trails]
The process of wicking then involves the heat slowly boiling more and more "stored" fuel deeper in the wick. Once boiled, the vapor rises to the surface. So, for the great bulk of the burn, ALL exterior surfaces (with the possible exception of the bottom) are dry. The flame cannot "touch" the kevlar because of the reaction corona in which fuel must come into contact with oxygen before the reaction can commence.
Kevlar comes into contact with flame when, and only when, it's not forming a corona around that part of the wick. In a square shape, the fuel in the center will migrate radially and thus take longer to get to the corners. This provides opportunity for long migration areas to get direct exposure. However, this is not a low fuel situation. Yes, it can happen during that time, but oddly shaped wicks like death stars, snakes, comets and multi-wick poi can suffer direct flame exposure during almost any part of their spin. And again, once the trails are gone from the ground, any wick that isn't perfectly aerodynamic could be cooking off a part of itself.
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