Hi Cardy
I'm wanting to make box hills with cast bulkhead edges kinda like this
http://www.warseer.com/forums/showt...og-Sci-Fi-Industrial-Necromunda-Inc-Timelapse
I've never cast anything before so my question is, is this a good place to start? Or am I being a little over ambitious? I want to make 4 x 18 inch squares so that's a 100 one sided bulkheads.......any advice appreciated!
It's really easy to cast bulkheads, you just have to make sure the silicone can't flow around the edges and underneath it. I'd recommend following the steps for making a two part mould, only doing the first pour and not the second. The result will be an open faced mould. You won't have to bother with the keying as it isn't a two parter. The bulkhead should be embedded into the plasticine deep enough to prevent silicone seeping underneath it. If your just casting the solid bulkheads this will be very easy as the only way it can get through is around the sides. The Gothic arch, door way and fan are a bit trickier. The door one is the easiest, you can simply glue a piece of plasticard to the reverse side of the doorway. If you add some hinges and a handle, a viewing slit, maybe some rivets, it'll look like a closed door. The other two are a bit trickier, but you might get away with gluing some plasticard over the back to blank it off like the doorway one, that'll preserve the detail. The detail just might be a bit thin and fragile immediately after it's set, so take care when demoulding, as the silicone might seep around the transoms and mullions of the arches, and the fan blade thingies of the fan one. This can be sorted easily when you demould the mould for the first time. A sharp knife to widen the channels will suffice. This will allow the resin/plaster to flow through the small channels easily.
Another note, if your going to be casting using plaster, make a surfactant bath to dip the moulds in. A surfactant breaks the surface tension of the plaster allowing it to fill the mould with fewer air bubbles. I use dish washer rinse agent and water. Just squirt a bit into a bowl of water and dip the moulds in.
For the amount you'll be casting it'll be far cheaper to use plaster, it'll be slower though as the plaster takes longer to set. The more moulds you make though, the faster it'll be!
Hope this helps!
Ps, if at any stage you need some advice on how to proceed, either stick it up here or PM me (photos of copyrighted stuff being copied might incur wrath onto the site so be wary!) and I'd be glad to help in anyway I can!