Help for coil shell

[dbanner]

I'm having a go at vacuum forming some coil shell housing for a dual field coil assembly.
I don't have good tools for cutting and shaping a mold from wood. I was thinking of using hard styrofoam but obviously it will melt when in contact with super hot ABS. Can some suggest a method for coating the styrofoam for heat resistance to make it into a more solid mold? Or is there simply no way of getting around this.

[rickb]

A handheld router with an attached arm between the router and a fixed point to allow you to adjust the radius of the cut might work. Good quality mdf having no grain should remain stable. DD or concentric?

[Goaty]

Can some suggest a method for coating the styrofoam for heat resistance to make it into a more solid mold?

You could try a wall filler such as Polyfiller to coat it. This has the advantage that it can be sanded to smooth and shape.

You could also coat the polystyrene with epoxy resin. The resin can be thickened with a filler such as microspheres (QCells) which also makes it sandable. Whatever you do, do not use polyester (fibreglass) resin as the polystyrene will disappear before your eyes.

[6666]

Cardboard coated with PVA sets like a rock

MDF and a hack saw blade will get you there, but slowly.

A jig saw and MDF works fine.

[dbanner]

Some good ideas, thanks people. Looks like I'll have to put in some work. At the very least, I'll have to purchase a jigsaw and some basic woodworking tools. But first, I must make the vacuum box! So I'll have to get the wood tools anyway, jigsaw will be right tool. All I have by way of power tools is an old Black and Decker drill.
I can already see that I'll need to drill holes to get the jigsaw on its way when cutting the shape. The styrofoam resin coated mold can work, but it involves just as much work as if I were to make the molds out of wood, so wood's the way, as they say.

[kt315]

do not remember your living in time of magic. take this cover for 4USD (chinese love USD). turn over and you get... the shell -!!!

https://www.ebay.com/itm/Metal-Detec...MAAOSw2ohd5LJL