Kevlar vs Carbonfibre drag washer

[Tiddlerbasher]

Has anyone used sheet Kevlar instead of carbontex (or similar). It is claimed to be superior in terms of friction co-efficient. It is also claimed to wear less. Both of itself and to the mating surface. Temperature tolerance is similar to carbonfibre. If all of this is true it should be possible to get the same drag with less applied pressure! That would indeed be good news for lever drag owners

The material can only be purchased ex factory in the UK - ie I would have to commit some serious money to this project. This is why I ask the question - has someone already tried it?

[Keta]

Give it a try and report back with your results.

http://www.cstsales.com/aramid_fabric.html

http://www.trickconcepts.com/Kevlar-Sheet-18-3mm-Thick-P1819.aspx?gclid=CNPOn-OwtLkCFUXhQgodxgUANw

http://www.hobbyking.com/hobbyking/store/__10756__3k_carbon_fiber_and_kevlar_29_cloth_180g_m2_1mtr_.html




http://en.wikipedia.org/wiki/Kevlar#Brakes

"Brakes

The chopped fiber has been used as a replacement for asbestos in brake pads. Dust produced from asbestos brakes is toxic, while aramids are a benign substitute"

[Dominick]

It would seem to me that Kevlar is too flexible to be used as a drag, or if it is sandwiched between metal it will not flex.  Just thinking out loud.  Dominick

[Bryan Young]

I guess you could use Aramid Paper for drags.  It's commonly used for electrical insulation.  I used to have a bunch laying around, and now...who knows.  I many need to find it and try it out.

[Robert Janssen]

http://alantani.com/index.php?topic=7909.0

It is claimed to be superior in terms of friction co-efficient. It is also claimed to wear less. Both of itself and to the mating surface. Temperature tolerance is similar to carbonfibre. If all of this is true...

Well, partly. Not the bit about temperature though, although aramid is adequately resistant to high enough temperatures for reel drags.

I guess you could use Aramid paper for drags.  It's commonly used for electrical insulation.  I used to have a bunch laying around, and now...who knows.  I many need to find it and try it out.

Good thinking. It is a very interesting material. But, i tried using it as a friction material, and no... It was just not useable. I don't recall the specifics, but no... That's all.

.

[Keta]

It would seem to me that Kevlar is too flexible to be used as a drag, or if it is sandwiched between metal it will not flex.  Just thinking out loud.  Dominick

I would glue it to the metal washers.

[alantani]

daiwa used red kevlar in some of their reels.  it was horrible.........

[Tiddlerbasher]

The Kevlar I intend to try (a free sample is on its way to me ) is not a soft sheet. It is a semi flexible material. It has been designed specifically for braking applications.
Technical info can be found here:

http://www.frictiontechnology.co.uk/contents/en-uk/d44.html

The product is FTL180. PDF now attached to this.

I have spoken with the people and single 300x300mm sheets (that's a lot of washers), .5 to several mm thick, can be supplied. Cost £29.60 excluding shipping & tax. So not as expensive as I orginally thought and substantially cheaper than a similar sheet of CF.!
The material can be operated continuously at 250C (482F), intermittently @ 350C (662F). If a reel drag gets that hot I think I would have other concerns Coefficient of friction remains constant @.58 to well over 250C (carbon fibre friction material is typically .45-.48, and can fade noticeably at these temperatures). This would appear to suggest an improvement of about 25% in terms of friction. My reasoning is - comparing Kevlar to CF - that is either more drag (at a given lever setting) or the same drag with less pressure on the drag system (less force on pinion and spool bearings).

From the spec alone it would seem to be ideal. But the real test will be what is it like to work with. Is it easy to cut or punch. From the test data I've seen it seems to run very smoothly (no mention of start up inertia) and can run with oil/grease or dry.

Back to the reel world I'm in the process of making an adjustable spooling jig (mainly for braid). The jig will use a 75mm diameter friction disc similar to a lever drag reel. With drag settings of 10-35lbs, running for minutes at a time, will test any friction material. This will also also be my test bed for the Kevlar friction sheet (I hope the sample is big enough).

PDF data sheet attached for the technically minded.

[Mandelstam]

Sounds interesting! Keep us posted!

/Karl

[jonathan.han]

You will still need grease. Salt crystallization will occur on anything. There is no avoiding that. Also, it would be interesting to see how the dust buildup affects the kevlar. We all have seen the glazing from CF. I wonder what the kevlar would be like. I wonder with the increased friction coefficient, if there will be more heat generated.

[Mandelstam]

Friction turns kinetic energy to heat (thermal energy). With the same amount of friction (drag) the same amount of heat is produced. If you can get higher drag with the higher coefficient, that will produce more heat. But the higher coefficient in itself won't mean more heat. It just means that you need less force to reach the same level of drag as with a lower coefficient.

Correct me if I'm wrong! I can take it!


/Karl

[Tiddlerbasher]

Karl that is my understanding - at the moment! I won't really know until I test it - still finishing the spooling jig and waiting for the Kevlar sample. Tribology (friction in this case) can turn into 'weird science'. Sometimes all the physics and math goes straight down the pan!

[Mandelstam]

Don't I know it! You just have to read the "Experimenting with the 113H drags" thread to be confused and have your beliefs thrown out the window... You wish you had remembered more from physics in school.

[Tiddlerbasher]

Rem?? something what from where

[jonathan.han]

I'm lazy and it seems like a lot of work. I'll stick to the old adage, "If it ain't broke, don't..."