Carbon Fiber Cloth???

[tampa1330]

I am building a SGX 67 rigger and need some CF cloth for reinforcing. I'd like to use the lightest gauge possible, but most of my sources are primarilty for automotive applications that use heavy gauge materials. The lightest I can find so far is about 5.8 oz per S.Y. I've been using a glass cloth that's made for RC planes and has a very tight weave with light gauge material. I was hoping to find a similar weight CF cloth. Any suggestions?

 

[tnrcboatracer]

I have some 3 oz. It's the lightest I've found. About $90/yd. But for reinforcing tubs, I prefer Kevlar. CArbon makes it stiff, but brittle. Kevlar makes it inpossible to tear. I make the Lynx from 2 plies of 1.7oz kevlar. One other benevit is that hte 1.7oz is only 0.004" thick.

 

[Terry Keeley]

I like the 3.5oz cloth which is the same 1K fibre but tighter weave, more carbon, less resin=lighter and stronger.

See the differences here: http://www.acp-composites.com/acp-sbwf.htm

Not cheap tho, they quote $100 per yard and it's prolly only 38 or 40" wide.

I'm sure Bob's right about the Kevlar, but I hate working with it!

 

[SayMikey]

I like the 3.5oz cloth which is the same 1K fibre but tighter weave, more carbon, less resin=lighter and stronger.
See the differences here: http://www.acp-composites.com/acp-sbwf.htm

I get mine on ebay several places on there have it. I have some kevlar but have not used much as i was told it will suck up water

 

[tampa1330]

I like the 3.5oz cloth which is the same 1K fibre but tighter weave, more carbon, less resin=lighter and stronger.
See the differences here: http://www.acp-composites.com/acp-sbwf.htm

Not cheap tho, they quote $100 per yard and it's prolly only 38 or 40" wide.

I'm sure Bob's right about the Kevlar, but I hate working with it!

more carbon, less resin=lighter and stronger

The last time I reinforced a tub I brushed on a light coat of lightly thinned epoxy and let it tack up. Then I layed the cloth in the tub and pressed it into the tacked up epoxy to hold it in place so the threads wouldn't come loose. Then I added a final layer of lightly thinned epoxy. It gave me a nice glossy finish but I think I could've used less resin.

 

[tnrcboatracer]

Yes, Kevlar can absorb water, same is tryue of Nylon. But the amount absorbed is miniscule. It mainly affects the compressive strength.

Terry, my light CF cloth may be 3.5oz, the roll is labelled 125g/sq M. It is a 1k 5HS made from T300 fiber. But I also vacuum bag it to pull out the excess resin to drive up the FV. 42" wide roll. Why don't you like Kevlar? Just don't sand into it.

You can also very lightly mist the part being laminated with 3M Spray adhesive to hold the cloth in place, then barely wet it out with resin. You can vacuum bag it to pull out the excess resin as well.

 

[Duck899]

Here is a link to a site that sells anything you need..... http://www.cstsales.com/products.html

Its available at hobby shops....Kevlar, carbon tissue, cloth.....

I've used the carbon tissue (veil) for fuselage sides as the center in a sandwich between balsa sides and the doubler in place of plywood doublers. West systems as the glue.... The result is a side that is lighter and stronger than the plywood doublers. Although weight is not as much of an issue with boats, you can get a glass finish in the tub.

 

[tampa1330]

I think I'm headed in the right direction. Thanks to all.

 

[Terry Keeley]

Yes, Kevlar can absorb water, same is tryue of Nylon. But the amount absorbed is miniscule. It mainly affects the compressive strength.
Terry, my light CF cloth may be 3.5oz, the roll is labelled 125g/sq M. It is a 1k 5HS made from T300 fiber. But I also vacuum bag it to pull out the excess resin to drive up the FV. 42" wide roll. Why don't you like Kevlar? Just don't sand into it.

You can also very lightly mist the part being laminated with 3M Spray adhesive to hold the cloth in place, then barely wet it out with resin. You can vacuum bag it to pull out the excess resin as well.

Yup, prolly what you have, that equates to about 3.7 oz/sqyd, the 2.8oz almost looks like cheesecloth the weave is so loose.

Tried a cowl with kevlar a long time ago and went nuts with the "fuzzies", guess if you don't have to sand, drill, cut, grind or look at it funny it's OK. :lol:

 

[Brad Christy]

Tampa,

Use the .5oz non directional carbon veil that ACP sells. It works great for reinforcing tubs. Wet out the wood with epoxy, IMMEDIATELY lay in the carbon, tamp it down the best and quickly as you can, then lay on a layer of .75oz glass to hold it down. If you lay in one layer just along the seams and then one layer over the entire bottom and up the sides about 3/8", the wood will break above the carbon line before the bottom seperates from the sides.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

 

[tnrcboatracer]

Veil is more for a surface layer under gel. It keeps the weave from telegraphing through. It's not very strong when compared to the woven materials. But something is better than nothing.

Terry, there are some tricks to Kevlar. Put CA on the edge after sanding to shape. Lightly sand again. Then wave a propane torch over the remaining fuzzies. Seal with epoxy.

 

[Brad Christy]

Tampa, Jon,

The carbon veil is plenty enough for securing the tub sides to the bottom and stiffening up the bottom. It also virtually eliminates cracking of the bottom at the bulkheads or along the edge of the tub sides, depending on which way your grain runs. I've been using this method in my BlackJacks and Crapshooters for several years now with excellent results, and these are all 1/32" ply on the bottoms.

Also, if you lay a bead of microballon filled epoxy into the seams and sand them into a nice fillet radius before applying your carbon/glass, you will have virtually inseperable seams with almost zero added weight.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

 

[tnrcboatracer]

Thanks for the tip Brad. I have some that I'll have to try. I didn't think it would be strong enough. We used it many years ago as a surfacing material on an RTM molded bike frame project I was on. Have a bit in the scrap box.