Ted

That's more then likely 5.7 oz CF, a standard that comes in 36 and 50 inch widths. The 50 comes with a yellow 3 strand end weave (BFG). The tape is most likely Amoco as the yarn manufacturer. The epoxy tale-up varies little however, with CF it has a tendency to float and trap. What that means is that it will float on epoxy given a chance, trap means it will contain the epoxy between the weave. Another issue with CF is that the filaments that make up the yarns don't do so well when seperated and tend to expand and hold epoxy (or vinylesters). This happens primarily at the edges and cut/damaged areas. To minimize the effects one vacumn bags or uses films and pressure.

CF acts with epoxy is different ways then fiberglass, and often results in less then desireable results. Also, CF yarns are not coated or treated like fiberglass, WYSIWYG. Bottom line it really is about all experience and technique. For instance, squeezing CF will force the epoxy out but it will then return to the space between the weave and if done too many times, it will then break the yarn (the 'tape') into fluffed filament bundles. In my experience, CF is far more exacting then most all fiberglasses.

For meaningful test results-and I'm not degrading your bench-test methods whatsoever- try a larger sample size and number of samples. larger sample size meaning test swatches. Number of samples mening several terst pices of each glass in order to reduce bias. For the s-glass and e-glasses; an interesting side evaluation would be to test the various finishes on the fiberglass weaves, from griege (meaning no finish) to types like 147, etc. You'll find the results quite interesting. Here's another one: try vacumn bagging. Now that's the way to minimize epoxy take-up.

I'm going to put togther a series of samples over the next few days and report the results, and I'll include kevlar which I'm unfortunately stuck with. The only kevlar anything I like is the hull of my sailboat.

I did do a little trial of using a CF filament winding onto a ground s/s 10/24 machine screw and I have to tell you, it was worth the effort! I now have one of a series of CF hatch screw-down fittings. Thanks for the great idea!

: The fabric came from fiberglasssupply.com, a sail board manufacturer on the
: Columbia River. Obviously they don't make their own fabric. The fabric I
: bought from them a couple years ago looks to be 5.8 oz. 2 x2 twill weave.
: They offer lighter weights, but not tighter weaves. In fact, I don't
: remember seeing an appropriate tighter weave carbon fabric at any other
: supplier either. I suspect that most of us building kayaks are using the
: same CF cloth, so my little test should be relevant for most of us.

: Ted