New to composites with questions about colored kevlar or hybrid fabrics

General Composites Discussions Composites Talk
#1

Well as the title says I’m new to composites and have been considering skinning some of the interior trim pieces in my Mr2. The interior is mostly black with the exception of the seats and the fabric inserts in the door panels which are bright red. The dashboard has an optional fake carbon fiber trim kit applied to it that is going south fast that I would like to replace with the real thing, but more on this at a later date.

I am considering doing the door panel inserts in either red Kevlar or a Kevlar / Carbon hybrid. The question I have involves the color difference between dry fabric and I guess the right term would be “wetted” fabric. While most of the images I have seen for dry red fabric would be a reasonable color / shade match, most but not all of the finished pieces using this material come out much darker, almost a blood red. Is this something that can be prevented or lessened to a large degree? Would a different fabric choice help or maybe a red tinted base coat (1st. layer of resin) vs a black or clear one? Any thoughts would be a great help. Thanks in advance, Scott.

#2

I used the bright orange dyed carbon kevlar and it went much more like a red/brown but still reflective somehow.

I can imagine there is not much that can be done to improve it. Adding tinted resin may only darken it even more??

This is a helmet that I did a few years ago. Bright orange kevlar carbon hybrid.

#3

Thank you Fasta for your reply. I have been thinking that using orange might also be a viable alternative but in reality I think that I’m just going to have to bite the bullet and go through the whole trial and error / experimentation process.

#4

There are other similar hybrids that are a polyester or other material instead of the dyed kevlar, maybe these ones will hold their colour better when wet out??

#5

Yeah, I have been looking at polyesters also. I may try to contact some of the people producing parts that have the end result that I’m looking for and try to pick their brains but so far your orange suggestion is looking the most promising. Nice work by the way.

#6

Do you have a pic of these materials after sitting in the sun for a while? I always wonder because I know how quickly kevlar will degrade and turn brown in the sun… remarkably fast. Even on a part that’s not done, if you leave some of it covered and there is enough UV, you can actually see the shadow develop pretty quickly.

#7

Is this still a problem when using a UV resistant clear coat or top coat or does that just mean that the clear coat will be resistant to yellowing while doing nothing to protect the underlying fabric?

#8

The helmet has UV clear of duratec but probably never saw much sunlight.

I have seen how regular Kevlar seems to bleach and change to a much lighter colour.

Maybe look into trying the polyester or fibreglass type hybrids as these will also be far easier to cut and work with unless you specifically need Kevlar in the layup?

http://compositeenvisions.com/composite-reinforcement-fabrics-2/carbon-fiber-colored-fiberglass-hybrids-99/

#9

My material options are completely wide open and are based on finished appearance only. Probably the only mechanical property to be considered if it can even called that is UV or color fade resistance. The car is stored for 6 months a year and only really sees daylight on the weekends for the other 6 months I’m not sure how much of a concern this really is going to be.

#10

Although the U.K. is not really my neck of the woods, I did come across this, Carbon Fibre Cloth Red Aramid Fabric 2x2 DUAL Twill 35’’ x 11’’
https://www.amazon.co.uk/d/1b3/CARBON-Fiber-Fibre-Cloth-Fabric-ARAMID-Twill/B01BMHDH18 Any thoughts?

#11

Hi Scott.

That amazon weave looks like very loose. Hard to work with , may fall apart easy. Can be fixed to a spray of 3m77

Check out composite envisions they have plenty of choice. Also you can email them and ask what they advise… But I’d say away from Kevlar for your first attempt.
1). Fading or browning they all do it.
2) hard to work with… Point being you can not sand Kevlar easy… It fluffs up , get fury on every edge you sand. It can be done , just takes a lot more effort.

I believe you can get just as good if not better result using dyed glass. Or carbon is just as easy.
Make sure you use a clear epoxy ( that stays that way once mixed) , as some will brown a little once mixed. Weather vac-bagging on you our panels or just wet lay up it will be a relatively simple process , knock the bumps and edges off with 240 / 320… Wet sand with 400 and give it a few coats of UV 2K clear. Oh…3m77 is your friend to hold everything in place on your part before wetting out :slight_smile:
Also composite envisions will send you samples of each colour so you can do some testing before you make your mind up.

Cheers
Tim

http://compositeenvisions.com/composite-reinforcement-fabrics-2/custom-dyed-fiberglass-129/?zenid=313474c3c95b7fa683f4d01a8af9fc05

#12

Thanks for the reply Tim, especially the point on the sandability (?) of Kevlar. I read about its abrasion resistance but that particular light bulb did not turn on. Regarding the link in my last post, I agree that the weave does appear very loose, I just thought the TrueColor or color stability aspect was interesting. So far Composite Envisions seems to have the fabrics that I am most interested in, especially the specialist weaves. Presently I am patiently waiting (or maybe not) for the sample packages I ordered from C.E. and Rock West I believe.

#13

That sounds like to could work given their blurb about it?

“The aramid fiber in this fabric is colored with our special TrueColor® Technology that keeps the color much brighter when resin is applied when compared to a typical colored kevlar that darkens when resin is applied.”

#14

hi Fasta. I am in NSW. Never dealt with Composite Envisions before. What is your experience with them like? I can’t find EnkaFusion CX100 50mm wide in Australia. Allnex only caries 100 mm wide. Composite Envisions carries 50 mm wide.

#15

I can comment also… No problem. They did have a bit of a rough patch when they moved to there new shed , so shipping some peoples orders got delayed quite a bit.
Me and a few of my mates have orded multiple times with no drama’s. It work out quite economic if you buy a descent quantity as it balances out shipping.

Cheers

Tim

#16

I had one problem with composite envisions where I bought a terrible coloured fibreglass, it was like it as painted with colour and so had set kind of stiff and was useless, I never used it.

Since I have purchased again and they are quite good.

I only use the 100mm enka channel from Allnex. You could just cut it in half to 50mm and tape the open edge closed again?

#17

Thank you for the feedback Timbuck and Fasta. I could cut it in half Fasta, but I am using around 40 metres in one shot. More convenient to buy a roll, and I need more of the 100 mm wide too.