Carbon fiber weave clean edges?

[sft2]

If you're going to be cutting a lot of kevlar, get a pair of ceramic shears. Mine are Kyocera, I believe. Cuts the stuff like it was glass. Don't use them for anything but kevlar or carbon/kevlar, though.

[keithbradley]

Just thought I'd post this here. This is a boat I just did a couple days ago. This was done with just carbon fiber fabric and epoxy resin, which was applied to the hull before and after the fabric was laid. This is probably a more difficult way to get a clean look if you're a beginner, but it ensures a complete bond with the hull through resin, not spray adhesive:

[PatrickM]

Here's a simple method that works great for any odd shaped ply layup.....
Cut a template to the shape of the area you want to cover. Cut the fabric oversize, wet it and squeegee out the excess resin on a piece of 1 or 2 mil plastic film. Bagging film or any thin polyethylene film will work. Lay another piece of film on top of the wetted fabric, trace the template onto the film and cut the stack-up to shape. Remove the film from one side of the stack and lay the wetted fabric in place, then remove the other piece of film. Tamp the layup in place with the bristle end of a brush to ensure that its in contact with the surface and to remove any trapped air. Optionally, you can mask off the perimeter of the ply(s) and any areas that you want to keep resin free, just be sure to remove the masking before the resin sets.

[bruiser77]

That turned out really good kieth! Nice work.

[siberianhusky]

Just tried the super77 adhesive, worked great, the best I've ever done.
Made a wooden roller out of a dowel and coat hanger, worked great rolling the resin into the cloth on the flat bottom of a cat hull.
Was able to get much better portion control by applying small amounts of epoxy and rolling it as far as it would go then adding a bit more. No puddles of excess resin this time! But fully wetted out cloth. Woo Hoo!

[detox]

I rather use fiberglass. The heavy weave carbon fiber I purchased from HK was more brittle than fiberglass when laminated with Pacer finishing resin epoxy (carbon fiber would break easily). Maybe if I use a better slower curing epoxy it may be less brittle. IMO the heavy weave just adds too much weight only. Lighter fiberglass weave is LOTS better.

I use the 3M spray adhesive alot...great stuff for lots of different projects.


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[keithbradley]

I rather use fiberglass. The heavy weave carbon fiber I purchased from HK was more brittle than fiberglass when laminated with Pacer finishing resin epoxy (carbon fiber would break easily). Maybe if I use a better slower curing epoxy it may be less brittle. IMO the heavy weave just adds too much weight only. Lighter fiberglass weave is LOTS better.

I use the 3M spray adhesive alot...great stuff for lots of different projects.


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You definitely did something wrong, because everything you just said about strength and weight is backwards. The advantage of carbon fiber is more strength and less weight. Use 3k tow size carbon fiber and the PT40 Zpoxy resin OSE sells. If you're not worried about appearance, unidirectional carbon fiber will also provide more strength than 2x2 twill or plain weave.

I have carbon fiber here that you can hit with a ball peen hammer as hard as you can and it won't break. If yours broke easily there was definitely something wrong. Maybe HK was selling something that's not really carbon fiber?

[detox]

I made some plate by laminating two sheets of the HK carbon fiber and finishing resin. Just for the heck of it I tried breaking a piece of it in half. It snapped fairly easily into two pieces. Maybe inferior quality cloth. IMO fiberglass cloth is strong enough for my hulls (cheaper also)

The .100" carbon fiber plate that HK sells is VERY HARD to break.

[Jeff Wohlt]

Wrong epoxy for what you are doing. FINISHING RESIN IS NOT FOR MAKING PARTS LIKE THAT.

[detox]

Wrong epoxy for what you are doing. FINISHING RESIN IS NOT FOR MAKING PARTS LIKE THAT.

But why would the carbon fiber snap in two? Seems it would snap and stay together.

[properchopper]

Just thought I'd post this here. This is a boat I just did a couple days ago. This was done with just carbon fiber fabric and epoxy resin, which was applied to the hull before and after the fabric was laid. This is probably a more difficult way to get a clean look if you're a beginner, but it ensures a complete bond with the hull through resin, not spray adhesive:

Nice job ! Link to where you got the fabric ?

[keithbradley]

But why would the carbon fiber snap in two? Seems it would snap and stay together.

To make parts like that you really need to at least vaccuum bag if not press it, prepreg cloth helps also but it's an expensive process if you want quality parts.
There are different types of fabric, some make harder parts that don't bend while other fabrics will have some give to them.

I'm surprised it snapped with no resistance, but I assume fiberglass would not have done any better if you did the same thing. The cloth is very strong, but if the curing process is done improperly it negates some of these properties. The most common problem is too much resin.

[keithbradley]

Thanks Tony!

I actually don't have a link to where that fabric was purchased, because that fabric was sent to me by the customer. The fabric was nothing special though, just 3k plain weave (2x2 twill will have the diaganal pattern where plain weave has the checkerboard look). I actually questioned using the fabric that's in that boat because it was folded when it was shipped, and the weave was badly distorted. I found the best spot of fabric I could and tried to fix the weave, then cut it so the imperfections were in spots that weren't as noticable. Wherever he got it from, I personally wouldn't reccomend them. Folding carbon fiber is a big no-no.

There are lots of places to get it though, probably some right in Cali that will save you shipping if you search "carbon fiber fabric". If you like the looks of the fiber in that boat, get the plain weave. The 2x2 twill is what you see on aftermarket car parts and looks like this:

[keithbradley]

I haven't personally ordered from them yet, but these guys have great prices and have some helpfull technical documents on their site that will help you decide what's best for your application:

http://www.solarcomposites.com/

[properchopper]

Keith, take a look at the stuff Jan is selling. I just fiberglassed a project boat interior 'cause I didn't have time to wait to get anything shipped( WWVIII in 18 days and SEVEN boats in seven classes getting prepped ) .Seems like the right stuff


scroll down a bit:

http://kintecracing.com/Building_Supplies.html