Best way to cut carbon fiber body work

[mbender]

Hello all,
I am trying to cut the carbon fiber/kevlar bodywork and panels that will go on our car, and I was curious what the best way was to do it. Last year we used shears and it did not work well at all, and we had pretty jagged cuts. I know there was a post on this in this thread awhile back, but as it was almost 10 years ago now, I was wondering if there was anything new out there?

Thank you in advance!
mbender

[MCoach]

If they are still floppy and just the cloth, big scissors that are sharp seem to do the job. Electric shears are another option. If it is resined but still soft, still the big scissors, don't want that garbage on any rotary tools.

Once it's cured and hardened, shears won't do the job anymore (especially if it's more than 2-3 plies thick), that rotary tool becomes your best friend. Set up a cut line and follow it along. Another option is a band saw, but whatever option you choose, make sure that you are careful to not delaminate the composite material. A mill is another option, but I'm letting you know now that there are special bits made for that.

Good luck.

[Francis Gagné]

Rotary tools and band saw are effectively your friends if the carbon is cured. But carbon and kevlar carbon are not good friends to tools, they wear them hard. If you go for a rotary tool I suggest getting a diamond grit one, they are not that expensive. For band saw a diamond grit if possible or very small teeths are better or you will probably splinter/delaminate the part. In any case put masking tape both side of the part to prevent splinters (or at least them getting everywhere, like your eyes or thumbs). As much as possible do it under a good sucking ventilation. For big jobs I prefer to put on a tyvek suit (painter suits) and a respirator mask. The carbon dust is very fine and gets everywhere!

[Rory Hourihan]

+1 for diamond grit rotary tool. Otherwise you'll go through about 100 cutoff wheels. also +1 for long sleeves, pants, and a respitaor. Unless of course you love being itchy forever. Once you blow your nose and have more carbon fiber than snot come out...you'll start to wear a respirator mask.

[mbender]

Yeah, before curing isn't really the issue, cutting with scissors works well. I should have been more clear. Sounds like diamond grit rotary tool may be what we do.

Thanks for the info!

[Z]

Mbender,

Or a jig-saw with an abrasive blade (ie. the small reciprocating (up-down) blade is toothless, but is covered in grit like sandpaper). These blades may nowadays be available with a diamond grit leading-edge. The jig-saws from China cost about $29, and can be replaced whenever the blades wear out. The jig-saw allows neater, tighter radius corners than a typical disc-type cutting wheel.

Oh..., and masks, long-sleeved shirts, etc., and vacuum extraction of the dust definitely does make the job easier in the long run...

Z

[MCoach]

As said above, when working with Kevlar you will always have a fluffy edge, just a fact of life. You can do very few things to get rid of it, but abrasive tools won't help with that.

Another +1 to diamond blades. Pretty much anything abrasive will do the job.

[Forbes]

A water jet cutter will leave a clean edge on both cured laminates of both carbon fibre and Kevlar (no "fuzz"!). Many aerospace composites manufacturers have one. Beware any reciprocating power tool - the pull stroke tends to bruise and delaminate the edges.

Forbes

[jlangholzj]

A water jet cutter will leave a clean edge on both cured laminates of both carbon fibre and Kevlar (no "fuzz"!). Many aerospace composites manufacturers have one. Beware any reciprocating power tool - the pull stroke tends to bruise and delaminate the edges.

Forbes

^^ this

most machine companies will also have a waterjet. We've had good luck with a bandsaw or rotary tool in the past but after trying a few samples with a waterjet its considerably cleaner.

[mbender]

Alright, Thanks!
I haven't done heavy searching into a water jet cutter, but from the looks of it that'll probably be out of our price range, at least for this year; as I know my team doesn't have one. The ME dep. at my school might though, I'll have to check it out!

mbender

[Rory Hourihan]

Well for body work I don't think delamination is going to kill you. As long as you're not running stressed body panels that is. Though it wont look as pretty. So, if you dont have access to a waterjet I wouldn't worry about it (Especially one that can cut the complex curves that are usually in body panels)

[Charles Kaneb]

For straight lines only, a hacksaw and masking tape isn't bad for rough cuts. Just don't tell anyone that you took one to their carbon fiber stuff, and do a good job finishing it so you aren't suspected!

[mech5496]

We usually use an angle grinder with really thin cutting discs. For detailed/small parts we use Dremel with even thinner cutting discs (that if you are not careful enough might explode into your face at some point)

[JWard]

We, err, I mean I knew of some people that made their own from a rotary pneumatic tool and a bolt to sandwich the disc. The thread at the bottom was turned down to be accepted into the rotary tool. They called it the death wheel for the same reason as above. They were scared it may inadvertently explode from too high an rpm. I wouldn't recommend this, but rotary cutting discs in general I would recommend as with all the above posts!

Hacksaws... not so much as they're reciprocating; but if you do, make sure it's very sharp (new blade)!