I have been asked to make a carbon fibre gun case, i would like it to be a clamshell design i.e two identical halves that will be hinged together.
it will have to have a good surface finish on the outside and rounded edges (something like 1/2" radius)
any suggestions on how to produce a mould for this?
Splash a mold off an existing one/master model. Depending on the clamshell lip, you might have to get creative, or just simply just make 2 box halves with a little bit of a flange lip. Maybe add a gasket on one side. Use commercial hinges and latches/locks.
Not knowing what EXACTLY it should look like, I think even just a mold that is a half-box would work well. See pic. Obviously deeper than that 
Is that machined aluminium? What’s the hole for?
and and i don’t know The block was scrap, and it happened to have a hole in the middle (back side with a cutout, and 2 bonded steel rods in the corners…shrugs) I filled the hole with epoxy and it’s fine now. Due to the VERY minimal draft, I might drill it out and put an air fitting on it, so I can blow off the part. Already damaged one trying to pull it out.
Work in progress
I was going to mention this… It is a good way to pop parts out like this. Just make sure you keep your hands away from the carbon when you put pressure at the other end… ;):D.
So if you use a mould with a hole in it to blow out the part after, is it filled with wax or something during use?
Your gonna want a tounge and groove around the edge of the case to keep it closed. Not to mention keep water out
you could probably use wax, but I’ve used clay.
Ok, I’m thinking of machining a pattern from wood, does anyone know what is the best type of wood to use? Good to machine and stable.
Yellow poplar is very good wood to use in pattern making. It’s close grained, easy to machine, and fills and paints very well.
Jon