Anyone out there home building carbon foils? I’m looking for ideas and inspiration for my next project. Does anyone have experience with using “cheaper” materials for female molds for prepreg? I can’t justify the cost of aluminum or even epoxy tooling board just for my little side hobby.
Here’s my latest little project, just pulled my first stab out of the oven. Prepreg carbon in a 3D printed mold with a 3D printed core. Turned out great and is insanely stiff and only 60g. 360mm span, 160 cm^2, AR of 8.1 with a mild anhedral. Modified H105 airfoil down to 9% thickness with a symmetric section on the tips for improved ventilation performance.
That’s very interesting. What material did you print with to ensure good stability when curing the prepreg? Also how did you cut the prepreg. My understanding was that you need heat and pressure so it’s typically done in an autoclave.
I printed with carbon fibre reinforced nylon, it should be relatively stable at 120deg C which is my prepreg cure temperature. I glued the printed mold halves to some aluminum plates to give them some extra dimensional stability and strength.
Cutting the prepreg is quite the rabbit hole… Currently I’m using a cricut sticker cutting machine. I’m maxed out on the cutting force that the machine can produce but I get pretty good cuts up to 200gsm prepreg carbon. The bonus is that I can export my exact ply shapes and even label each one then cut them all and it makes layup and finishing much easier.
I have an industrial oven so I have a PID controlled temperature cycle. The pressure is achieved by the compression in the uncured plies. i.e. the uncured plies are about 30-50% thicker than the cured plies so I control the number of plies in all areas of the layup to give me enough compression. The resin system I’m using is net so I seal the perimeter of my mold with o-ring cord stock to stop any epoxy escaping and that helps maintain the internal pressure as well.
