Lumenier RB2205C-12 2400KV SKITZO Ceramic Bearing Motor
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Old Oct 17, 2011, 07:33 AM
dydx is offline
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Cutting Kevlar


Hi All

I was just wondering what folks out there use to cut kevlar? I've never worked with it before and don't seem to have anything in my shop that can give me clean edges on the 75gm cloth that I'm using for doublers.

Do I need a pair of those special serrated shears?

Cheers
Pete
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Old Oct 17, 2011, 07:35 AM
Alex.Schweig is offline
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Give a good pair of Fiskars the Samotage treatment and youŽll be cutting golden fabric in no time!

https://www.rcgroups.com/forums/showthread.php?t=657516
Old Oct 17, 2011, 07:58 AM
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Thanks Alex, Samotage, I'll give it a go
Old Oct 17, 2011, 08:16 AM
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I use some scissors from the Dollar Store. They are used for cutting leather, they look something like this:
http://www.amazon.com/gp/product/B00...6JQX6XXTS1JVJ7

It's all in the angles of the blades, Phil Barnes has solved this inexpensively also:
https://www.rcgroups.com/forums/showthread.php?t=795224

Curtis
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Old Oct 17, 2011, 09:38 AM
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+ One for the re edged scissors. I dont have a sander, i re edged mine on an off hand grinder.


LB
Old Oct 17, 2011, 10:24 AM
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the serrated scissors are great, but they done last long .. i tried to keep mine only for kevlar but when you see how great they cut everything else you just cant help yourself *shrug*

so now i grind an old pair and they work great again ...
Old Oct 17, 2011, 10:57 AM
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grinder vs sander


i find that using a (stone) grinder only makes the edge dull and rounded. for a while, i could not figure out why this technique was not working. then, i tried using a sander and it worked really well.
Old Oct 17, 2011, 11:41 AM
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Key IMHO is you don't really want a smooth edge. You want one with tooth so the fabric cannot try to slide down the blades. You also want a right angle edge on the blades because the action is not a cutting action but a shearing action.

Gerald

PS - By "tooth" I mean coarse sanded so the sanding striations are clearly visible. Smooth is no good.
Old Oct 17, 2011, 06:50 PM
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Ditto what GT said. Think in terms of something like 60 grit.
Old Oct 18, 2011, 01:22 PM
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I purchased the fiskars with the serrated edge for Kevlar and I hate to say it but they do not cut light kevlar as easily as Phil's modified scissors do. Plus they are cheaper and when they do ot cut, a quick hit with sandpaper, file or grinder and they are as good as new. the serrated do cut the heavier stuff but then again so do Phil's.

Thanks Phil for disclosing this idea......
Old Oct 19, 2011, 05:18 AM
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Little trick for cutting small parts:

Mark your shape on the Kevlar, apply some CA on the cutting line, leave to dry, then cut the Kevlar with normal scissors.

Only works if the Kevlar is applied on single curvature surfaces, since the fibers are stuck.
Old Oct 19, 2011, 05:47 AM
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Contrary to what everyone uses, I have a very expensive (120eur) scissors that cuts everything, from 25g glass to 200g kevlar without any hassle.
I had a pair of modified scissors, but they needed re-sharpeneds every few cuts, I guess they were not heavy duty.
My expensive scissors only see dry fabrics; to cut wet fabrics, I have a pair of curved scissors that also are expensive (60eur) but they cut everything and are good for working with molds.
I have never regreted to buy the expensive tools, since cheaper one did not show reliable to me (they would get dull mostly when everything was in the mold and I really needed to cut the stupid kevlar).
Old Oct 19, 2011, 07:11 AM
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Probably Robusto Proton scissors?

http://www.robuso.com/shop/details2....000&CatID=1010
Old Oct 19, 2011, 08:07 AM
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Are both blades micro serrated or just one on your scissors?

Who sells the ones you suggest?

I am not sure how cost effective those are but I wonder if using a coarser file/sandpaper/grinder would yield longer lasting results?

I think it is the biting ability of the roughening up or the serrations that allows either set to work.
Old Oct 19, 2011, 10:49 AM
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Quote:
Originally Posted by chetosmachine View Post
Contrary to what everyone uses, I have a very expensive (120eur) scissors that cuts everything, from 25g glass to 200g kevlar without any hassle.
I had a pair of modified scissors, but they needed re-sharpeneds every few cuts, I guess they were not heavy duty.
My expensive scissors only see dry fabrics; to cut wet fabrics, I have a pair of curved scissors that also are expensive (60eur) but they cut everything and are good for working with molds.
I have never regreted to buy the expensive tools, since cheaper one did not show reliable to me (they would get dull mostly when everything was in the mold and I really needed to cut the stupid kevlar).
I agree. I've got a pair of ceramic edged scissors that have lasted 3 years without the need to be resharpened.

I also agree that the Fiskers serrated edge scissors are a total waste of money.


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