Plasticast is a moulding compound with very useful properties. It has properties somewhere between ceramic and plastic, but its strength development is gradual, allowing easy alterations while working.
Plasticast is made from a resin and a ceramic powder, which can be mixed in different proportions to give putty, paste or pourable consistency.
Typically it is mixed in the ratio 2 parts powder to 1 part resin, poured into a rubber mould and stripped after half an hour. (As soon as it gets warm)
Around 5 minutes after mixing it can be smeared, after 10 minutes it can be cut with even a credit card, after 15 to 20 minutes it can be cut with a knife, after an hour it gets warm from setting, and can be stripped after 35 minutes. It can be sanded easily after 45 minutes, but after 24 hours you need power tools to machine it. It is homogeneous and smooth and very amenable to all kinds of mechanical working.
Times mentioned are influenced by temperature and mixing ratio:
The density is low; 1,3 grams per millilitre at 2 parts powder to 1 part resin.
The colour is a pale beige, with low opacity, so it responds well to pigments. It is compatible with all mineral fillers in our experience. Hollofill (cenospheres) or coarser Pratliperl perlite can be added to make it lighter, or zircon flour or barium sulphate may be added to make it heavier. Other mineral fillers may restrict the machinability. Water dispersible fibres may be added for reinforcing.
Plasticast will adhere well to most surfaces, and it bonds particularly well to previously cast Plasticast. (Sanding it wet may cause the additions to come unstuck). Thus additions may be made to your workpiece as easily as subtractions. Waxes make good release agents. Plasticast is good at cleaning moulds.
Plasticast may be laminated like fibreglass, using open-weave fibreglass matting.
Plasticast expands slightly, around 0,3 % on setting, which can make it unsuitable for some rigid moulds, and extremely useful in other cases.
Plasticast is not flammable, and stable up to 200°C.
Packed in 3kg kits of 2kg powder and 1kg resin, or larger quantities.