Quote:
Originally Posted by old greg
I'm going to nitpick some of your nitpicking 
Prepreg with a core material is totally possible and is done all the time. The only really impossible combination is VARTM with a honeycomb core (you need to use a foam core instead).
It could also be that the weave was skewed when the fabric was laid up. |
What I meant was that the design (use of cores) is not really intrinsic to pre-pregs, while everything else is (except weave, oops).
Basically what I meant is that if you use pre-preg, you automatically have a properly mixed epoxy matrix around the carbon, that won't cure unless it's under proper heat. Whether the manufacturer uses a core is up to them.
Edit: Not doing a good job with clarity lately...
Let's try this again. The use of pre-preg cloth reduces the amount of less-expensive 'substitutions' that can be made. If you get CF pre-preg it is only CF, and only specifically measured epoxy has been already applied to it. The options that a manufacturer can cheap out/make choices on are the weave, the design/core use, and part of the curing method (pressure/vacuum but not heat). And due to the cost of the material, it is less likely that a company will take short cuts.
The likely only variances in pre-preg part designs would be the choice of weave design, fabric weight, core choice and use, and whether it is vacuum-bagged and baked, or pressure-cured under heat in an autoclave. (But I believe it is
possible to simply layup and heat-cure it without pressure/vac but I doubt this is ever done.)
Also with that Elise in the pic it looks like wrinkles on the surface, rather than a smooth surface (which should have been against the mold) with distorted fibers. When I've seen bad CF parts, the exterior shape is generally good from the resin filling the mold, but the fibers get pulled apart inside the resin.