The case is a large, hollow Bakelite shell, it’s fairly simple in design but it’s large, or rather it’s large enough to make casting a copy of it difficult for me to imagine.
Can anyone tell me:
1. Can this case be replicated in resin? 2. How difficult it’s likely to be if I’ve only ever created small casts before.
The case is about 16” diameter; 6” deep and 1/8th inch thick.
The back is simply thick cardboard so that’s easy to copy; the knobs are very easy to copy too and I’ve had great success with them.
My reason for wishing to replicate the case is mainly because I want to create a Bluetooth version of this radio, but I don’t want to mess with the fully working valve original as it’s a reasonably rare radio.
If I can create a decent resin copy of the case, I can modify it however I like and not worry if I damage the case or have to cut bits out of it while experimenting.
If anyone can talk me through how I might make a mould for resin casing this shell, I’d be very appreciative. My main sticking point is the fact that it’s a hollow, rounded shape that’s circular; I just can’t visualise how I can make a mould that will produce a hollow shell of his size, although the Bakelite original must have, I assume, been cast too...
I did try vacuum forming a copy but that did work at all well. Also the Bakelite, while sound and strong, is probably brittle so I don’t want to stres sit too much.
Ok so can someone show me an example of something similar that’s been cast? If anyone can pony me to a guide on making this type of resin mould I’d be grateful.
My main concerns are:
How do I support the outside of the mould when I’m casting? I tried smacking a mould (it takes a phenomenal amount of casting material) and it just buckles when I try to it.
This radio case is big - it’s a good 18” diameter and the walls are only 1/8” thick.
I need someone to show me an example of someone casting something similar as it just doesn’t work when I try it.
Scaling up isn’t as easy as just slapping more material on and everything working as it would as two thirds the scale. Once you get to a large size with thin walls and there’s a good 6” depth to the walls, things quickly go wrong.
I’m specifically looking for an example of someone doing this which a detailed guide. I’ve tried and failed too many times at this cast to be wasting more time on trial and error. There has to be a specific way to achieve this: a detailed, planned way. There must be methods / techniques to doing this exact thing - that’s what I need to know.
FYI I’ve wasted over £200 on failed moulds so far.
Anyone have a good, detailed answer on how to achieve this cast?
As far as supporting the outside of the mold, you will need a box (wood,metal) to help keep the mold contained. It sounds like the walls are too thin as you state that it "buckles" Try looking for some Youtube videos on large scale resin casting ...there might be one within the video section at Alumilite.com the videos should provide you with the detailed answers more so than I can. If you still have your failed molds, they can be cut up and used for filler should you need to add to your existing mold as silicone bonds to itself quite well.