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Problem wetting out fabric

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Old 05-17-2004, 02:36 PM
  #1  
weskel
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Default Problem wetting out fabric

I am having trouble getting some kevlar to wet out with west systems epoxy, is there any tricks to make the fabric accept the resin better. I have heard some fabrics have a "sizing" on them, would it help to wash the kevlar before trying to lay it up?


any help would be appreciated


weskel


P.S. just to let you guys know why I'm messing around with this Kevlar, I basically have a large supply of this type of Kevlar and I am trying to get some use out of it.

I know there are better fabrics to use, but when you have it free you want to use what you got!!
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Old 05-19-2004, 11:03 AM
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Default RE: Problem wetting out fabric

You can try warming the epoxy so it flows better and that should help. But if the Kevlar has the wrong finish on it, you may not have much luck.

-David
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Old 05-19-2004, 03:30 PM
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Mluvara
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Default RE: Problem wetting out fabric

Kevlar is naturally tough to wet out. I tend to only lay up using kevlar on components that I can vacuum bag. Try heating the resin as Dave described or press the resin in with vacuum or weight. Not sure if you could wash any treatments off.
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Old 05-21-2004, 09:41 AM
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weskel
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Default RE: Problem wetting out fabric

Mluvara,

Do you vacuume bag parts?

I was wondering if I sent you a sample of the kevlar I have, could you play around with it and let me know if it is going to be usable for models.

I dont have a vac setup and do want to get one, just dont have the time rght now. I would like to know if this stuff I have is worth hanging onto or just discard it and get it out of my shop.

Let me know if you are willing to test some of it, I am willing to send you some.

If you dont have the time, maybe someone else can help me out.

weskel
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Old 05-21-2004, 11:31 AM
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Default RE: Problem wetting out fabric

Weskel,

You didn't say whether you were using this Kevlar in a mold or on Mylar's. I have used a lot of Kevlar in both molds and for vacuum bagged wings and never had any problem with the fabric wetting out. Are you experiencing a beading effect with the epoxy and fabric? What exactly are you experiencing? You might try a layer of light glass cloth on both sides of the Kevlar, kind of a Kevlar sandwich.

Bill

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Old 05-21-2004, 11:42 AM
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Default RE: Problem wetting out fabric

Hi!

You can try pro-set resin.....is very low visco

Dave
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Old 05-21-2004, 12:56 PM
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Mluvara
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Default RE: Problem wetting out fabric

Weskel,

I do vacuum bag parts and I've found that is the best way to layup any kevlar parts. I'm a little busy at the moment, but if someone else wants to try your kevlar out, that might be the best way for you to have another opinion on its properties.

Michael
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Old 05-21-2004, 01:12 PM
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mattyd
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Default RE: Problem wetting out fabric

Try putting kevlar and resin between two sheets of plastic sheet and apply pressure by hand this sometimes helps.
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Old 05-21-2004, 03:10 PM
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weskel
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Default RE: Problem wetting out fabric

If anyone here would like for me to send them a couple yards of this Kevlar here I will, all I ask is let me know the results you have with it.

Obviously I cant send some to everyone, but I will send it to the first who asks.

weskel
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Old 05-21-2004, 04:54 PM
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Default RE: Problem wetting out fabric

I Sent you a PM - I'm going to be molding some jet intakes next week (Friday start) and will be using both regular West Systems and their big brother ProSet.

I'd be happy yo check it out while I've got my vacuum system out and the molds waxed.
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Old 05-21-2004, 08:43 PM
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Default RE: Problem wetting out fabric

I believe this Kevlar has a water resistant treatment on it, but it is the only kevlar I have ever messed with. I took a piece of it a while back and put down some clear plastic sheeting, brushed on some west system epoxy, layed the kevlar on it then brushed some more on the other side. I then put another piece of plastic on the top and wiped the top of the plastic with a piece of ply wiping out alot of the excess resin.

When it cured, it felt like it had wetted out fine, but when I cut it with scissors the fiber were still "dry" and "stringy". I know that sounds funny but I dont know how else to describe it. It was like the resin only stuck on the outside of the fibers and never penetrated.

I'm just curious if the stuff is worth hanging onto.


I don't build anything that would require kevlar, but on some scratch build "weird" birds I build it would look really cool to lay it up and dont paint it.


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