Machinable mould making materials

[Sven]

Don't use plaster, it is very corrosive on tools.
As far as machinable wax goes, I've read some info on disolving PE shopping bags in to candle wax (keep on disolving until no more gets disolved) gives you maxinable wax.

Mdf can work too, have tried but for bigger molds. Used epoxy to seal it, then sand smooth.

[Musht]

Thanks guys , thought had heard Tufnol /SRBP dust was bad, but looking up the MSDS just an irritant, bit on order from ebay.

Tried MDF but chepa stuff furrs really badly , especially at the scale and sheet of Valchromat bit more than need at mo.

Lost contact had for chunks of Corian like solid surface, if they were any bigger thna door wedge began to get expensive. Would use acetal as next favourite material to cut , not cheap though.

Looked at mix your own wax route , slightly concerened that any impurities might inhibit platinum cure silicones, dosent take much ;-)

For try before buy, committing decent cutter and material have settled on cellotex at moment.

Read abit about plaster not being as hard on tools as might think, its just calcium carbonate, and adding some PVA to mix helps bind it keeping dust down. Idea seems to be cutting it when its still damp or soaking the brick for a while before cutting, Ideal for taking latex moulds from but think shrinkage of plaster and latex will begin to add up.

Will report back on using tufnol clone