etusch wrote: ↑
Wed Nov 08, 2017 8:39 pm
It's logical. I don't know how they're working . I am trying to do something with carbon fiber and mould making materials are more expensive than carbon fiber itself. If it's not serial production they can choose this way at least for trial designs.
I don't know which resin system you're using, probably rtc wet layup, if so, then your mould materials (especially if you're just experimenting) are basically anything, wood, plywood, mdf, foam board, etc, use automotive soft (polyester) bondo to do final shaping, spray some 2k primer on it, sand it and then spray 2 component automotive clear coat, wet sand, buff, wax and you're ready to make your moulds for parts, clear coat is necessary, because the vynil or polyester gelcoat that you'll be using, will dissolve and grab onto the bondo or the 2k primer used for the model, don't skip it
and again - if you're just learning this, use regular polyester resin and gel coat for your moulds, they will work for room temperature epoxies (or vinyl) you will use with carbon, just don't lay up too many layers with epoxy, or it will cook the mould when it goes off, and don't build all the mould layers in one setting, do 1-2 layers (~400gr glass per layer) a day and let it cure in room temperature - this is the opposite of what some mould specific resins require
mould specific materials (the expensive stuff) are for long lasting moulds, they have stuff in them that reduces shrinkage, which basically means they keep their shape better (important for larger parts), they may hold higher temperatures - so may suit some prepreg carbon etc, and mould gel coats are a bit tougher than what is used for general production of gfrp parts
this is all very general, if you would share what sort of parts you're making, I (and probably other users here) may help with specific things