Carbon Fiber

No it is not much different than glass.  It does not like to go over compund curves as much.  If you don't want to paint it so you can see the CF pattern, that is where it gets difficult becuase you can't do much sanding.  Other places to look for materials:

www.aircraftspruce.com

www.fiberglast.com

www.cstsales.com

www.carbcom.com

I work with carbon and kevlar quite a bit feel free to hit me with any more questions.

You can use polyester resin just fine.  IMO it is easier to work with than epoxy, it costs less, so unless you are using it in a heavy duty structural application feel free to use polyester.

The best way to get a nice smooth finish is to build up your structure like you would with glass, then make sure your last layer of CF is smooth, flat, and if possible made from one piece.  Then apply several coats of resin to build up enough over the fiber that you can sand it down without cutting through the fiber.  You also have to be careful to not get bubbles in the resin becuase they will come out as pinholes.  One good way to apply the resin w/o bubbles is to thin it and spray it on w/ a spray gun.  You can polish the resin with the same polishes you use for polishing paint.

The colored fiber is Kevlar, it is not as strong as carbon, but it is stronger than glass, and it is literally bulletproof.  It is a complete PITA to work with because it is extremely hard to cut.  If you ever have to sand it rather than a nice smooth edge you end up with frayed edges because the resin sands away but the Kevlar doesnt.  It can make for some cool looking stuff though, this is a closeup of a  b-pillar on my car:

-- couple of things I forgot---.  Another way to get a nice looking smooth surface is to apply a couple of extra coats of resin, sand it down and then coat it with an automotive clearcoat.  This is an especially good idea for something that will be in sunlight because the sun might fade the colored Kevlar, and over time sun will break down the resin and make it yellow.

Oh, and the b-pillar pics, are that same fiber you see at Shopmaninc.com

     What would you use to thin the resin for spraying. Also, the general purpose resin that I use has a nasty green tint that would not be acceptable for clear applications(This is never visible from the exterior of my enclosures). Is there a particular type and brand of resin that you would recommend that would not add color to my projects? 

     How thick do you normally build your enclosures when working with fiberglass or CF? When I built my last set of kick pods they ended up being 3/8" thick(including fleece) for a 5 " driver. It may sound like overkill, but panel flexing is not an option with my installs. On small flat areas I reinforce the fiberglass with rope or coremat. Do you have any other ideas? Thanks for all the help.

Use Styrene to thin polyester resins.  You can find it here:  http://www.shopmaninc.com/solvents.html  I am not sure what to thin epoxy resins with, I have never tried it.

The b-pillar pics I posted are made with (believe it or not!) plain old Bondo resin, which has a brown color.  For plain black carbon it actually looks better than with clear resin, it gives the CF more "depth".  I'll try and remember to scan in a pic of some CF kickpanels I am working on.  Shopman sells clear resin (they call it surfboard resin) that does make the hybrid fabric look a little better.  http://www.shopmaninc.com/polyesters.html 

A rule of thumb to remember for carbon fiber/epoxy construction is that a high quality layup is just as stiff (but not quite as strong) as a steel panel of equivalent thickness.  Unfortunately for us DIY types the equipment to make "high quality" layups is out of our reach, so figure for a polyester/CF layup 3 times the thickness of steel gives the same stiffness.

When making flat panels there are several things you can use for a core to make what they call a sandwich panel.  Now for an engineering lesson--  In a loaded panel the outer "skin" takes most of the load, so you can make the core out of a comparably very weak material and end up with a surprisingly stiff/strong structure.  I have a panel at home that I plan on making a seat back from that is 1" thick styrafoam with carbon skins that are about .100" thick.  You can stand on it without damaging it, but it is very light.  Both www.aircraftspruce.com,   www.fiberglast.com, and www.cstsales.com have several core materials ranging from end grain balsa wood to structural foams and nomex honecomb.  They all work well, so choose what you like and can afford, we are not making aerospace hardware!  Just make sure that what you choose will work with polyester resin if that is what you plan on using, some foams melt when uncured polyester contacts them.

I keep remembering things that might help after I post!

Easiest way to make a flat, nice looking CF panel:  Buy a sheet of plate glass, clean it then wax and buff it a few times with an automotive wax. (Meguires works very well they sell basically the same wax to the composites industry and call it mold release)  Spray the glass with a couple of coats of thinned resin.  (You could also use a paint brush, just make sure the resin layer is uniform in thickness, and without bubbles)  When the resin gets tacky lay down your layers of CF, then spread resin on (one layer at a time, to avoid bubbles).  Don't use too much hardener so you can spend some time trying to work out the bubbles.  put a layer of peel-ply on, followed by a layer of bleeder/breather cloth (both available at several of the online stores I listed)  Put something flat and heavy over that to compact the laminate.  Let it cure, peel off the peelply, then use a razor blade to peel up the edge of your laminate.  You will have a nice looking, flat, and (if you are lucky) bubble free composite.  The only thing you need to do to make it look perfect is clear coat or polish.

      Would vacuum bagging reduce the thickness of a composite piece? If it does, do you know how to build a DIY vacuum pump or would an ordinary shop-vac produce enough suction to get the job done?

     Also, does the rule of thumb you mentioned previuosly apply to the total thickness of a part built with a core material or just the composite layers themselves?How does epoxy resin affet the weight and strength of a layup? And speaking of layup, will layup resin affect the way saturated pieces of glass adhere to vertical surfaces?

     Thanks for all of your help.