D.I.Y. Carbon FIBER - ?

[Craig 930 RS]

Looking to make some non-structural CF items - shrouds for air inlet stuff, etc.

Has anyone done this kind of thing - what should I expect, what have you made,
what do you think of the process you used?

Source for components for a DIY setup?

Fire away -

[jhelgesen]

http://www.fibreglast.com/

[Peter Bull]

Craig,

unless you've made glass fiber reinforced plastic (GFRP) parts before, start with that rather than with carbon fiber reinforced plastic (CFRP) parts. The reason is that it is very easy to see when you've wet out the glass fiber properly. It turns transparent. Carbon on the other hand stays black so the only way to know the laminate is good is experience, or non destructive testing.

/Peter

[Craig 930 RS]

Is there a setup where black may be used?

[Tim Hancock]

Craig, a friend of mine who builds aerobatic airplanes for a living uses lots of carbon fiber and he likes to wet out both fiberglass and carbon fiber with "Proset" epoxy. It is made by the Gougeon company who also makes West System Epoxy. I have used it myself with thin glass cloth for fiberglass skinning plywood wings. It is thinner than most epoxies and can be post cured with heat. http://prosetepoxy.com/

Another friend of mine makes wood aircraft propellors and on the ones he skins with carbon fiber, he uses West System epoxy.

I have not actually laid up any carbon fiber parts (although I have built lots of parts out of fiberglass), but have watched my buddies do it and IIRC, you can tell when you have the air bubbles work out. The thinner Proset I mentioned, wets out much nicer than thicker epoxies. FWIW, most folks building aircraft parts use some form of epoxy as the resin as opposed to the old polyester resin used in the past for auto/marine fiberglass.

The main thing to remember is that you simply want the least amount of resin required to thoroughly wet out the cloth. Their are many ways to achieve this, the simplest being to work/force the resin into the cloth with a squeegee or roller, then work any cloudy areas with a short bristled brush to force the air out till it is clear. ANother way which requires a bit more stuff to do is to vacuum bag the parts over your mold which draws the excess resin (and air bubbles out of the part.

Play with some cheap woven fiberglass first,as carbon fiber cloth is stupid expensive.

[Peter Bull]

Originally Posted by Craig 930 RS

Is there a setup where black may be used?

I'm not sure I understand your question. My point was that it is easy to see when you've worked the air bubbles out and the resin into glass fiber, on carbon fiber it is difficult.

It can be good to practice a little with some glass fiber first.

/Peter

[Jeff Alton]

CRP is much more difficult to saturate than most fiberglasses, making it difficult to get full saturation with out a resin rich lay up. Too much resin makes a part brittle.

The Geugon Brothers know their stuff, and proset and west systems are both good products to use.

Small nap rollers (the little ones) squegees (not the kind for washing windows) and stiff brushes are an absolute requirment. A special ridged metal roller that helps force air out is a good idea too. Also, a really really good pair of large industrial scissors for cutting the CRP fabric is needed.

Cheers

[Ken911]

the epoxy doesnt work well in the sun though. most of the west sytem and gougan brothers epoxies recomend paint for uv protection. the polyester resin can be pruchased with UV inhibitors. which was not available a few years ago when I was making woodedn boat parts.

[Shaun @ Tru6]

I laid a layer of triax carbon fiber mat over an 8 man wooden rowing shell (1960's vintage) that was not worth restoring. Rollers, rollers, rollers to get the West System into the mat. Lot of work. Will never do that again, but the boat-cum-barge trainer came out great, practically indestructible.

If I were making non-structural, smaller parts, I'd consider making molds out of various ceramic plasters on the maket, use prepreg mat and build a no-pressure autoclave, otherwise known as an oven. I believe that both pressure and heat are necessary for structural parts in useing prepreg, but if just shrouds, etc. where aesthetics are primary, I think just heat might work for a very nice, lightest, cleanest part.

[Porsche_monkey]

Real carbon fibre is baked in a vacuum isn't it? Faux carbon fibre is like fibreglass. Which do you want to make?

[JeremyD]

I've done my share -

Like others have said - start with fiberglass cloth and get some experience with that first.

here's another good source. http://www.fgci.com/index.html

Be careful with the CF cloth - there is some real crap on the market right now - seems the govt is buying up all the decent stuff these days for the military.

If it is non structural - you can wet it out like fiberglass -

Your best best is epoxy and CF - you will have to clearcoat with a UV inhibitor or the epoxy will yellow -

Best bet is to use some light weight cloth - get some practice and then move up - it really is an art form to do well.

[cgarr]

This company has all the DIY stuff is you want to try it. You can even get some sample kits to try.

http://www.aircraftspruce.com/menus/cm/carbonfiber.html

[Jeff Alton]

Originally Posted by PBH

Real carbon fibre is baked in a vacuum isn't it? Faux carbon fibre is like fibreglass. Which do you want to make?

What?

Vacuum bagging can be done with any laminate as a way of ensuring full saturation with minimum resin for strength and light weight. Using heat speeds up the reaction of the cure....

Cheers

[island911]

Originally Posted by Shaun 84 Targa

.... use prepreg mat and build a no-pressure autoclave, otherwise known as an oven. I believe that both pressure and heat are necessary for structural parts in useing prepreg, but if just shrouds, etc. where aesthetics are primary, I think just heat might work for a very nice, lightest, cleanest part.

No, not really. You need the pressure, especially w/ CF. ....CF is not very drapable. ...it doesn't want to bend in the fiber direction. Also, if you use no pressure the resin (even in prepregs) will migrate as heat allows it to flow. This also means the 'tack' of the prepreg goes away, allowing those stiff fibers to straighten from the curves of the mold.

(my first gig out of school; aerospace composites.)

[Shaun @ Tru6]

Originally Posted by island911

No, not really. You need the pressure, especially w/ CF. ....CF is not very drapable. ...it doesn't want to bend in the fiber direction. Also, if you use no pressure the resin (even in prepregs) will migrate as heat allows it to flow. This also means the 'tack' of the prepreg goes away, allowing those stiff fibers to straighten from the curves of the mold.

(my first gig out of school; aerospace composites.)

That is good to know, though I would be using very lightweight mats that can drape fairly well, especially when compressed in a mold. I've got the Ultracal and have done some testing on molds and Al panel beating (rear decklid first test), the result was to think about testing a layer of prepreg mat between two weighted mold halves and just bake it.

Was the business manager for a pultrusion start-up (Bauer CF hockey sticks, Browing Arrows, sail masts, Stealth Bomber air intakes, Kestrel graphite tube testing, phenolic cable tray, etc.) so I know just enough to get into trouble.

Still have some interesting rolls from those days.

[WolfeMacleod]

Craig, for DIY Carbon Fibre, I think you should check my two recent posts regarding a place called TechShop that is coming to Seatttle soon...

posts are here: TechShop update
and here: TechShop is coming to Seattle!

Looks like the TechShop in CA had Carbon Fibre classes....

[island911]

Originally Posted by Shaun 84 Targa

....that can drape fairly well, especially when compressed in a mold. ....

if it's compressed, then you -are- applying pressure.

[Craig 930 RS]

Is this a meeting for the possibility of a CF, etc workshop - or is TechShop actually coming here?

[avendlerdp]

Vacuum bagging is the way to go for anything curvy. One can make some pretty simple systems using vacuum bagging film and even just a shop vac.. I would not trust this far anything structural but for ducts, scoops, panel hatches and the like you should be fine. There are lots of room temp curing epoxies out there as well. Try a small project first to get your sea legs. You will be surprised how strong even crude CF parts are.

[Craig 930 RS]

Either of these look like a decent way to 'get my feet wet'?

http://cgi.ebay.com/ebaymotors/Carbon-Fiber-Kit-Fabric-Cloth-Resin-Instructions-19-oz_W0QQcmdZViewItemQQcategoryZ26438QQihZ017QQitemZ 4641873302QQrdZ1QQsspagenameZWD1V

http://cgi.ebay.com/Carbon-Fiber-and-Epoxy-Resin-Kit-Do-it-yourself_W0QQitemZ330173607864QQihZ014QQcategoryZ1 267QQssPageNameZWDVWQQrdZ1QQcmdZViewItem