Postby TPink » Thu Apr 03, 2014 4:46 pm
Jaw,
I have just finished laying up my carbon foil and it came out great.
I respect tkettle's reply but don't necessarily agree.
First off, I used the 5.8 cf cloth as well. I just measured a piece of it holding it up to a mm ruler and a magnifying glass, and it is at least .5mm or more. certainly more than .2 mm.
Second, there is little value in a solid laminate piece, particularly if you want to acheive approx 10-13mm total. Mine (strut/front wing) came in at 12mm all up with final clear coat.
All modern layups for grand prix sailboats use a composite sandwich comprising and inner and outer skin covering a core of either some type of foam or wood (usually balsa). it is this method that gives you the stiffest and lightest part, Imagine an I beam.
CF is increadibly strong in tensil strength, meaning that it resists stretch along the bias of the threads. To achieve stiffness along the length of a piece, you need to have the opposing skins of the part resiting the forces that want to bend it. That can be achieved by a pure carbon part, but it is only the outside layers of carbon that are acting to resist the bending forces, meaning the inner layers are unnecessary, and heavy.
My strut and wing have a balsa core of say 9mm, 3 layers of CF on each side, totalling 6 layers.
Of the 3 on each side, 2 are oriented 0/90 bias to the part, 1 is 45/45. This provides ample stiffness along the part and torsionally to prevent twisting.
I mean to tell you, i can not grab both ends of my strut and either bend it along its length or twist it at all! and the all up weight of the entire foil (strut/frontwing/fuselage/rearwing) is 1.2 kg. !
My suggestion to you is to wax the molds with release wax, hit with one or two coats of clear, then lay up 3 layers of your 5.8CF, using the orientation i mentioned above. Then you could either fill each half with a foam or thin sheets of balsa & thickend epoxy to fill the center. That will produce the stiffest/lightest parts.
Good luck with it!