Tilted Forum Project Discussion Community - View Single Post - Working with Carbon Fiber (and other composites)

texascwby7 · 07-06-2007, 09:01 PM

I work at an airplane component composite manufacturing plant. All of our stuff is the prepreg and we bake it in an autoclave to activate the resin. Do not do this in your home stove. THe gases from the resin can impregnate the walls of the interior of your oven and your food will be tainted.
Our molds are either composite molds or aluminum molds (hard, smooth surfaces, not like clay). for controllers and other shells, you would probably need female molds ( so clay mold to plaster to another plaster). The side that is on the mold surface is the smoothest. You'll need some sort of release agent on the molds. I'm not sure if you can get the good chemicals, but since your small timing it and possibly without baking it you can use a mix of dawn soap and water or a grease. get a dixie cup and fill it about 1/8th or 1/4th of the way with dawn and then the rest with water and stir. Apply that to the smooth mold surface. You want it to be very thin....it's like greasing aa pie pan. The prepreg can cure without baking but it takes a day or more depending on the resin matrix. wet layup is easier and usually sets faster. When your're laying up the plys, if the outside surface ply is glass and the next is carbon, then you'll get a glossy look. A clear expoy resin (for example look up http://www.toolchemical.com/products...scriptions.htm ) applied to that surface can smooth out imperfections and keep that glossy look. You can thin it with acetone to make it flow better... any of the resins you choose.
The carbon material drills fine. It can be hard on blades. Sanding, will take a coarse grid to get anywhere. 80 or coarser. You don't want to sand the surface that you'll be looking at....i.e. the controller surface. You'll mess up the weaves and it'll look terrible. Use the molds to controll the surface shape and smoothness. Use multiple plies to create thickness and sand off the backside if you have to sand a surface. one ply of prepreg laid up and cured is about 0.010" thick. Wet lay up (dry plies laid down and wetted with resin) are the same thickness. trimming and sanding the edges are fine to get it to shape.
that's all for now

07-06-2007, 09:01 PM	#4 (permalink)
texascwby7 Upright	I work at an airplane component composite manufacturing plant. All of our stuff is the prepreg and we bake it in an autoclave to activate the resin. Do not do this in your home stove. THe gases from the resin can impregnate the walls of the interior of your oven and your food will be tainted. Our molds are either composite molds or aluminum molds (hard, smooth surfaces, not like clay). for controllers and other shells, you would probably need female molds ( so clay mold to plaster to another plaster). The side that is on the mold surface is the smoothest. You'll need some sort of release agent on the molds. I'm not sure if you can get the good chemicals, but since your small timing it and possibly without baking it you can use a mix of dawn soap and water or a grease. get a dixie cup and fill it about 1/8th or 1/4th of the way with dawn and then the rest with water and stir. Apply that to the smooth mold surface. You want it to be very thin....it's like greasing aa pie pan. The prepreg can cure without baking but it takes a day or more depending on the resin matrix. wet layup is easier and usually sets faster. When your're laying up the plys, if the outside surface ply is glass and the next is carbon, then you'll get a glossy look. A clear expoy resin (for example look up http://www.toolchemical.com/products...scriptions.htm ) applied to that surface can smooth out imperfections and keep that glossy look. You can thin it with acetone to make it flow better... any of the resins you choose. The carbon material drills fine. It can be hard on blades. Sanding, will take a coarse grid to get anywhere. 80 or coarser. You don't want to sand the surface that you'll be looking at....i.e. the controller surface. You'll mess up the weaves and it'll look terrible. Use the molds to controll the surface shape and smoothness. Use multiple plies to create thickness and sand off the backside if you have to sand a surface. one ply of prepreg laid up and cured is about 0.010" thick. Wet lay up (dry plies laid down and wetted with resin) are the same thickness. trimming and sanding the edges are fine to get it to shape. that's all for now