Researching White Metal Casting

It remains quiet on the modeling front with the arrival of a new baby into the house and the fact I’ve recently started a rather full on new job! Last week I did have a brief email conversation with the helpful staff at TopMark regarding white metal casting. I’ve since decided to stick with resin casting for the interim but am recording the material details and pricing here for future reference.

TopMark identified two of their RTV products that would be suitable for white metal casting:

  1. M4670 at 500gm for $72.30nz, or 1kg for $120.00. The base colour is beige and the catalyst is clear. It is a 10:1 ratio by weight with a cured hardness of Shore 55A.
  2. Premium Blue at 1kg for $164.70nz. The base is white and the catalyst is blue. This silicone can take the highest heat up to 400 degrees C and has a cured hardness of Shore 50A.

Of the two the Premium Blue is probably the most attractive because it can be mixed ‘by eye’ due to the coloured catalyst, much like I do with Ultrasil RTV. M4670 is cheaper but mixing a 10:1 ratio product by weight is a hassle as it would require me to purchase some accurate kitchen scales and actually measure things.

These two silicones also have a Shore hardness harder than Ultrasil which is low at 25A. So they’re not as flexible in a thicker cast and I’ll probably need to go thinner to get the flexibility of Ultrasil. Mind you if I’m splashing molten pewter around I’d be quite happy to have a more rigid mold!

TopMark also sell various raw metals, with the most interesting being:

  • JA12, 1kg at $75nz. A quality casting pewter, suitable for small pieces of jewelery, key rings etc. It is an excellent casting alloy giving fine definition, high strength and superior polishing characteristics. Contains a small amount of lead. Casting range: 275-330 degrees C. Ingredients: Tin major, Copper 0-2%, Cadmium 0-5%, Lead 0-10%, Antimony 0-10%.

They also had a JA8 metal that looked quite good at $40nz/1kg but unfortunately on reading the ingredient list it turned out to be almost 50% Lead! That makes it less than desirable for casting small items people are going to file and handle regularly.

The other costs associated with white metal casting would be picking up a Butane torch and a crucible of some kind. Butane torches can be found in most auto-repair stores and I suspect TopMark may also sell crucibles, but I neglected to ask them. All up that’d probably be an extra $50nz or so on top of the cost of the high temperature RTV and white metal. So in summary that’d be quite an outlay just to set myself up to do some experimental metal casting. Hence I’ll stick with resin for the time being.

Interestingly enough after I posted my WIP Pulp luggage to several relevant Pulp gaming forums I’ve had a few offers of people interested in doing bespoke white metal casting – including some spam from a Chinese factory. I’m tempted to take them up in their offers (not the spammers mind) but would probably have to re-master both pieces of luggage which while not overly onerous would be a touch annoying.

I’m also halfway through sculpting a couple more luggage items too – a carpet bag and a simple box tied with twine. Once they’re finished I’ll mold the lot and see how they cast in resin.

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