quote:

ORIGINAL: alanc

i machine carbon fibre parts for formula 1 race cars, i am told there are many differant grades, and weaves, and that the stuff is baked, doesnt sound the same as glass to me, but, i only machine it, not make it

quote:

ORIGINAL: DMcQuinn

Carbon Fiber cloth can be used the same as fiberglass cloth. You can use an epoxy resin to saturate the CF cloth. Then form it into or onto some pre-waxed mold. It will cure in 6 hours or so ar room temperature (cure time depends upon the epoxy). No heat / no autoclave is required. It is really no harder than fiberglass. Once cured the part can be cut with saws, drilled with drills, etc. I have some example CF parts on my web page:
http://webpages.charter.net/mcquinn/Dave/RC/Projects/projects.htm
I have made CF spinner, prop and landing gear.

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ORIGINAL: alanc

The stuff i do is wound on a mandrel from sheet, in multiple layers, each layer being a differant density, and grain direction to the last, the tube is sometimes tapered, sometimes the shape is very much like a flashlight, i bore and trun the things for steering columns for Mclaren, and one or two others, i use the hardest of carbide, one tip edge does 1 job, on the next bore, i rough it out, and change for finish cuts, on a 5 of, i will go through about 120 dollars worth of tips, another job i do is for a bearing cage, for satelites, this stuff is WAY harder, and gives me PLENTY of grief, i am not alowed to use abrasive, to remove burred edges, to make 4 simple rings, it takes nearly 9 hours!!! then the miller has to drill the holes through with a diamond cutter--thing is, we are cutting diamond with diamond--losing battle, we win, but at a hefty cost in tooling, lot of my stuff is floating around in space now, lot of it is flaoting around various race tracks, as well [:D][:D]

next time the guy brings me some of this grief, i will ask him how they make the stuff,

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ORIGINAL: TeamSeacats

The dust will cause "black lung" as your body cannot rid itself of the dust in soft tissue. Take precautions.

quote:

ORIGINAL: alanc

It comes off as a powder, and the poster above is right, it can be drilled and sawn, just not for long, carbide is needed, or diamond for pure carbon fibre, i am no expert in the composition of the stuff, only the machining, but, if used in some model applications, if pure carbon is used, say in an undercart, then it will shatter on a hard landing, there must be other additives

sorry, cannot show the machining proccess, dont think the bosses would like it!! its not hard, just time consuming, and the cost of the parts means take your time, i just finished a simple bracket for a satellite it looked like a pawn off a chess board, it had a 2mm cored hole, weave was wound on a 2mm mandrell, the parts where 12mm diam, 40mm long, 10 off, no spares for setting, material coast was in excess of £700, not all carbon is the same, believe me!! scary thing was, the end was threaded internal for a helicoil, (carbon cannot be usably tapped out) our guy fitted the wrong helicolis, and had to take them out, trouble is, he pulled the thread out as well!! we got clearance to open up to a bigger diameter, just as well, eh!!

one thing, the dust is not cancer making, but it is unpleasant, i wear a good mask, and have very little skin exposed , dont underestimate this stuff

quote:

ORIGINAL: DMcQuinn

Carbon Fiber cloth can be used the same as fiberglass cloth. You can use an epoxy resin to saturate the CF cloth. Then form it into or onto some pre-waxed mold. It will cure in 6 hours or so ar room temperature (cure time depends upon the epoxy). No heat / no autoclave is required. It is really no harder than fiberglass. Once cured the part can be cut with saws, drilled with drills, etc. I have some example CF parts on my web page:
http://webpages.charter.net/mcquinn/Dave/RC/Projects/projects.htm
I have made CF spinner, prop and landing gear.

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ORIGINAL: wings_of_fire

quote:

ORIGINAL: TeamSeacats

The dust will cause "black lung" as your body cannot rid itself of the dust in soft tissue. Take precautions.

OMG! .....thts something to take care off ...seriously. Thanks for letting me know that. R u related to carbon fibre in any way ?

quote:

ORIGINAL: DCX

You think fiberglass is inchy.....nothing compares to getting a little dust on your arm or wrist. I also machine the stuff. Mainly short run bicycle racing steering tubes and suspension systems. I have had much luck with pinning the stuff with a small screw to lugs. Currently I machine diamond with diamond. Composites wern't hard enough anymore!! My background is with "pre-preg" tubes only that I have made in the US, drawn from a mandrel. I was the first to develop actuators with the material. Mono-filiment surfaces can be heald within aceptable tolerances to employ as a ram rod with other hard plastic bushings combined with kevlar wear surfaces. Cold process nitride coatings can also be applied for prevention in areas of potiential wear.

Ultrasonic testing of all machined parts is the only way I have found to test for internal fracturing-defects. This may sound silly, but plain old quality High Speed Steel cutting tools works fine and is the only thing I use, however they require slow feed and medium speed.

Some times when I am using LockTite, and cleaning out old threads (in carbon graphite) it will ignite! Some chemistry issue, talk about smelling bad.

Wrap receipe; there is much to learn about shear in the specific applacation and wrap direction of the material. I would like to see more of the Pre-pregenated (pre-preg) epoxy materials being used for RC hobbies. Rather than just layups. With only 2% resin in the final piece. Who is this guy??...fact, this kind of process is almost totally prohibitive for us kinds. Autoclaves with tons of pressure that only make the cure heat with only the applies pressure to a prepreg layup. A "dry process" if you will. The sprayed epoxy material is self bonded with no heated parts, but heat up only with the enourmous pressure applies to the mold. Greg Trimble holds the patent for "Vacuum bagging of carbon-graphite layups", Wasen't he a smart fella with that one. I supported his racing team with my suspension forks for a couple of years. But again my point is that composites have more to offer than the wet lay-up. Grain strengths of 460,000 PSI!

So I only work with the dry lay up material. Easy to work with if you follow many, many long learned skilled. On can't learn to machine with this stuff, you have to know how to read what your working with. Listening to what what others say is heart warming to say the least, I've been there!

I'm still leary of disclosing too much regarding this material. I believe that there is much to gain with tinkering, however this material has it's drawbacks. Contuined good luck to all you fabracators out there. Sorry for the long read. I'll keep my eye on this list & hopfully contribute when I can.

Happy New Year Everyone

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I work with it periodically as a hobby - no big deal really...it works just like fiberglass but as someone already mentioned, high fiber to resin ratios are where the big weight savings are gained. You can machine it with regular tools - they just dull quickly and the higher fiber to resin ratio you have, the more wear it puts on the tooling. High end tools will certainly last much longer. Much of the laminations I do are vacuum bagged but I have not worked with pre-peg heat set or autoclave processes. Shown here is a foam core radio tray for an r/c sailboat

quote:

ORIGINAL: wings_of_fire

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I work with it periodically as a hobby - no big deal really...it works just like fiberglass but as someone already mentioned, high fiber to resin ratios are where the big weight savings are gained. You can machine it with regular tools - they just dull quickly and the higher fiber to resin ratio you have, the more wear it puts on the tooling. High end tools will certainly last much longer. Much of the laminations I do are vacuum bagged but I have not worked with pre-peg heat set or autoclave processes. Shown here is a foam core radio tray for an r/c sailboat

how is the Fibre to Resin ratio calculated during processing? how do i know what Fibre to Resin ratio will give me a particular strength desired in the processed carbon fibre part ? I was just going through weikipedia to find out what pre-peg means, (i did find the answer[:D]) ....so r the resins in the pre-peg carbon fibre of a diffrent type than the normal epoxy ones?