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"Alloy question for use with PA molds" Topic


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364 hits since 9 Sep 2016
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Lord Marcus09 Sep 2016 9:49 a.m. PST

Hi PA fans I have a question. although I have enough model metal in my order to last, one of my acquaintances has a bar of the following alloy available. Would it be good for casting in your molds?
35% tin / 1.5% antimony /2.5% cadmium / Bal. lead

Mako11 Supporting Member of TMP Inactive Member09 Sep 2016 12:31 p.m. PST

Can't comment in an educated manner on different alloy mixes, since I haven't personally used them, but that being said, don't see why not.

Back in the day, I recall mention of "lead" being used, but of course that might have been a mix of different alloys too.

Make sure to wear a filter when casting, or do it outside, where you can get fresh air.

Lord Marcus09 Sep 2016 12:51 p.m. PST

I will be doing so. My primary concern is the cadmium as I can't find reference to that being used in material that would cast in vulcanized rubber.

GarrisonMiniatures Supporting Member of TMP Inactive Member09 Sep 2016 4:02 p.m. PST

Cadmium in alloys:

link

Generally, antimony and cadmium help with things like flow properties or reducing the alloy melting point. The tin:lead ratio is similar to many early wargames alloys and is still used by some companies today – the metal I used for Garrison figures was about 5% antimony, the rest being 50:50 tin:lead.

GarrisonMiniatures Supporting Member of TMP Inactive Member09 Sep 2016 4:08 p.m. PST

Actually this one gives a good idea – you're looking at ones like grade 34.5 or grade 37.

link

Zargon Inactive Member09 Sep 2016 4:38 p.m. PST

You need to ask for something called 32-2-2, I think this is a set of ratios for perfect white metal used in miniatures, the othe thing I've heard of is WM90 but not sure this applies to white metals universally, you need to get hold of a supplier and ask what they supply locally. Hope this helps.

GarrisonMiniatures Supporting Member of TMP Inactive Member09 Sep 2016 4:41 p.m. PST

No such thing as a perfect ratio – depends on method of casting, size of castings, detail/undercuts, how brittle/bendable you want it, cost.

Generally the more lead the cheaper, but with higher melting point and less detail.

Lord Marcus09 Sep 2016 8:08 p.m. PST

I would be exclusively casting 25mm skeletons

nevinsrip Sponsoring Member of TMP09 Sep 2016 8:23 p.m. PST

I would be exclusively casting 25mm skeletons

Less lead, more tin. 60-40 is better since skeletons will be thinner and it will be harder to fill the cavities.
He's talking PA molds NOT spin casting.
Hand pouring will require a more fluid mixture.

GarrisonMiniatures Supporting Member of TMP Inactive Member10 Sep 2016 2:10 a.m. PST

'He's talking PA molds NOT spin casting.'

Same principles apply – it's an art rather than a science. How fluid depends, for example, on getting the temperature right. Additives like antimony are to help flow, so again help. Lead is a funny one – high lead don't flow as well as high tin, but this is balanced by lead being a far denser metal so it is 'heavier' – useful in drop casting.

The simple answer is try it – certainly, before I found the mix that worked best for me I tried several different ratios. Then found that as I gained more experience I could get most things to work… though spin casting… same with drop casting. The metal is important, technique and practice are what really makes a difference. It helps if everything you cast is pretty much the same in terms of size and pose though – again, spin casting but illustrates a point, casting small figures I had to spin faster, large figures slower. I also found that some individual moulds had their own characteristics…

Lord Marcus11 Sep 2016 12:48 p.m. PST

Again the main objective I had with this thread was to see if the following alloy is suitable.

35% tin / 1.5% antimony /2.5% cadmium / Bal. lead

Personal logo Steve Roper Supporting Member of TMP30 Sep 2016 10:24 a.m. PST

I am no alarmist and am not afraid of lead, but cadmium and cadmium fumes are very toxic. That would rule it out for me.

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