SuperTrans Man

I had a few things I wanted to fiberglass, Ive worked alittle with fiberglass and Im prity sure that I can get what I want done with it but my question is how hard is it to work with kevlar? Ive never worked with it before and I needed something alittle more flexable then fiberglass for what I am doing. I have the molds all made up and Im just trying to figgure out if I should just stick with what Im good at or try something new. That and I dont know what kind of propertys of kevlar are, and I was hoping to find someone with experiance to help out a bit.

scooter

iTrader: (11)

I dont know a whole lot about kevlar but I have heard that it is hard to cut, so you need a really good set of shears (scissors)

I H8 WWD

iTrader: (5)

What is it you are trying to do?

SuperTrans Man

Just a few interior projects center console and a few other things, not quite car related but I was wondering how hard it was to work with and if it was more bendable then fiberglass after its dryed. I would assume its like fiberglass soak mold in resin/hardener apply coat dry and repeat. But I was really wondering if the propertys of the kevlar itself was that much diffrent then that of the fiberglass as far as strength, ridgidity ect.

Camaro5690

iTrader: (1)

isnt kevlar used in bullet proof vests?

jccaclimber

Kevlar isn't hard to cut. Kevlar is a b**** to cut, but really it's worse than that. You want serrated scissors at the very least, and also, you CANNOT sand kevlar at all. The edges just fuzz up forever. Also, kevlar is not as good at draping over edges as fiberglass.

Vader

"Bullet proof" vests are just like "bullet proof" glass - They only work against small and/or soft bullets.

Have you considered graphite carbon fiber instead of glass or nomex/kevlar/aramid fiber?

LIL BASTARD

iTrader: (3)

What are you after, the cool pattern look of kevlar and carbon fiber, or just something that's better. Glass is probably the easiest to mold, and it should be plenty strong enough for interior stuff

Six_Shooter

iTrader: (2)

There are specific shears for cutting Kevlar/aramid fibre, that do not leave a serated edge.

Working with Kevlar is closer to the likes of working with Carbon Fibre, and less like working with Fibreglass.

You need to squegee the excess resin out, so that the mat lays flat and tight to the mold/gelcoat.

Speaking of resin, you need to use the same rsin as carbon fibre for a strong bond to the matrix material (Kevlar/aramid in this case), for some reason the tyo eof resin is not coming to me, too earkly I think. LOL

I'm also curious what the projects are.

jccaclimber

I did not mean that it leaves a serated edge, just that if the scissors have a fine serration it is much easier. Otherwise the kevlar will try to slide out. Carbon can go either way but it has been my experience that thicker carbon (10 oz twill) was also stiffer than fiberglass (but much stronger). To be quite honest, I've never seen anything as flexible as fiberglass. Also, the "need" to remove the excess resin is weight and cosmetic, it will technically work if you don't. Really you should look up vacuum bagging or use a compression mold. Carbon you can sand (watch for those splinters), fiberglass you can sand, kevlar you cannot. If you must use kevlar, put 1 layer of fiberglass over it so that still sand the edges of you final product. Any 2 part epoxy should work with it (well, really any glue, just not very well). Aircraft Spruce has a good selection of epoxies. If you want to see my carbon experience, I used to work here: http://www.hedcycling.com. Also, the body of this bike is one of my more recent carbon/kevlar jobs:http://www.rose-hulman.edu/hpv/.

SuperTrans Man

LOL its a secret, but seriously I had a new idea for a center console and some of the plastic interior peaces but Im concerned with fiberglass' flexability because from my experiance (very limited) fiberglass is fairly brittle and would can cause stress cracks if its flexed as far as kevlar goes can I add a layer of fiberglass over the top to sand with the resin? it sounds like I would have to glue it on from what I read but that doesnt sound like a good idea to me I dont know. Also its not for a looks thing as its going to get painted/covered but I want to find something that will fit my application and bottom line is I want to find soemthing that can flex alittle without the fear of it cracking. If theres a way to get fiberglass to do this Im all ears but I havnt seen it so I wouldnt know. Thanks for all the interest in my little projects but I dont want to start posting it until its all done I hate seeing someone post something thats half done and having to wait weeks/months to see it finished. lol. Anywho Thanks everyone for the input and I hope to have a dissision made about the material that I will be using by the end of the month and the molds covered by the middle of next month at that point Ill start posting some more details on the projects and the finished results.

jccaclimber

When you said flexability I was thinking flexability of the fabric rather than the final product. Kevlar will be far less prone to cracking (in my experience). You would add the last layer of fiberglass the same way you add the layers of kevlar.

Jay87Z

iTrader: (2)

It all depends on the materials used. I have a vest right here that will stop 7.62mm armor piercing rounds. Kevlar definately won't stop anything more than a small round though.

fireturd350

iTrader: (8)

Personally I'd go with some nice biaxial fiberglass. Doesn't fall apart as easy as plain mat and much easier to make around corners and position than full out woven stuff.
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Also like to add fiberglass can be brittle, but that depends on your resin ratio you mix up, how many layers you do, type, and general shape of the project. If I make a solid flat piece of course I'm not going to want to use fiberglass. I could easily use wood or metal for it, but if it has a curve fiberglass gets pretty strong. I had a sub woofer box I could stand on (270+ lbs).