Benefits of kevlar over fibreglass?

Iamzod

Iamzod

Iamzod

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Quick (i think) question!

Say you were to take two identical body panels, one made from fibreglass, one made from kevlar what sort of benefits are there to going with the more expensive kevlar parts?

I hear of fibreglass sometimes having a rippled finish when painted dark colours, is it the same with kevlar?

Thanks
 
The Kevlar part will be a little bit lighter and probably a bit stronger. Given that we're talking body panels, depending on the car I'm not sure the Kevlar ones would make a whole heap of difference.
 
dont think fibreglass does have a rippled effect when painted dark

/me rund to garage to check bottle green cobra...

nope

it all comes down to the finish


kevlar will be stronger than fibreglass for the same panel
 
JRS said:
Given that we're talking body panels, depending on the car I'm not sure the Kevlar ones would make a whole heap of difference.
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Mk3 Ford Capri X-Pack Wings & front valance, so quite large panels.

I know that ford used fibreglass wings when they did the original 3.0 X-Pack's back in the 70's, and the parts available today are supposed to be the same parts made by the company that did the originals for ford and are therefore a really good fit.

The kevlar versions are made by another company but still only cost £150ish more.
 
Iamzod said:
what sort of benefits are there to going with the more expensive kevlar parts?
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Bragging rights.

finish on composite (GRP, kevlar, carbon et cetera) panels is down to the quality of the mould.

due to the nature of the material, a kevlar panel is more likely to show its weave through a coat of paint.

*n
 
Iamzod, what about fitting mk2 capri xpack panels instead? They look a lot better on mk3 capris if you ask me, I had a black 3.0s with fibreglass ones fitted, it looked amazing and a lot rarer than the bubble arched mk3 ones.

Oh, I'd go for kevlar/fibreglass mix by the way, fibreglass on its own cracks a lot easier. ;)
 
Wicksta said:
Iamzod, what about fitting mk2 capri xpack panels instead? They look a lot better on mk3 capris if you ask me, I had a black 3.0s with fibreglass ones fitted, it looked amazing and a lot rarer than the bubble arched mk3 ones.
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I prefer the MK3 ones as they look a lot more subtle, besides i'd be using the kit that replaces the entire front wing so i'd be able to avoid modifying the existing steel wing, as far as i know they dont do full wing versions for the MK2.
 
Kevlar is a woven sheet, therefore the weave can be directed and angled precisley to give strength in certain directions whereas fibreglass cloth is a random weave meaning you have less strength. Kevlar is also a stronger material in general making it even stronger. Kevlar is more expensive. Fibreglass is heavier becasue more layers need to be laminated to give the equivilent strength of kevlar. The paint finnish is all to do with prep and the quality of the part itself.
 
Not quite Huzee :D Fibreglass comes in woven mat as well, and roven weave or whatever it's called when the stands in the weave are twisted as well for added strength. Same with carbon.

Kevlar is much much more flexible than glass fibres so less likely to snap. Layer it up and the flexible strands just deform dissipating energy into itself and grab whatever you try and throw through it, hence use in bullet proof vests. Carbon, because the strands don't stretch can be made a lot stiffer than glass for the same thickness, hence it's deemed lighter.
 
If your talking about ply stacks alignment to give any composite more strength in certainly planes then it will typically be a UD tape lay up, not a woven cloth, particularly the crimpled cloth tye as that prevents the fibre strands achieving complete alignment and hence effects the component stiffness.

For auto body panels there no real difference structurally as bolt on panel dont do much, theres certainly no ply orientation optimisation so fibreglass cloth is just as useful. Particularly in motorsport GFRP is the best choice simply down to cost of replacement parts.

Is this an off the shelf part or something you are looking to make, as resins and cure methods are just as important as the fibre choice.
 
I thought most glassfibre pannels were made from a random weave pattern though, im not sure so dont own me if im wrong. It thought carbon/kevlar pannels were woven more precisley and glass pannels made with randomley woven fibres. I thought because it costs a lot to make precisley woven mats that they dont bother to use fibeglass because for the small added cost to the overall product they might as well use carbon. Im not 100% sure but when i did a project on composite fishing rods this seemed to be the case.
 
Yeah Fibreglass matt/cloth wont be a woven structure, just a random aligned short strand sheets using mass produced method which is perfectly fine for most application you will ever see Fibreglass used in.
 
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