Softening and Hardening Metal Miniatures

[ErikB]

I'm sure we've all experienced this.  I am wondering if anyone has a solution.

We want out metal minis to be hard so they don't bend while being handled, right?

We also want them soft so we can bend them into position, drill holes for spears and for pinning joints, and so on.

I am wondering if there are ways to use heat to harden or soften our metal minis.  I do have access to a soldering iron so I can apply very high heat in pretty small areas.

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If you are wondering, I am trying to figure out a smart way to improve the strength of the sword on Footsore's Lancelot mini (https://cdn.shopify.com/s/files/1/0657/9717/products/03ART003_large.jpg?v=1416863748)

The mini is incredible.  The one little catch is that there is a small, 1-2mm portion of the sword hilt above the hand of the guy.  (Imagine a real sword with the hilt a little longer than your hand.)

That one tiny little part is bending a lot and I want to make it stronger.  For now, I am applying some super-glue and will expect that the primer and paint will make that point a bit stronger.  Worst case, I replace the hand and sword with a spare from my Gripping Beast spares. 

The mini will be fine but this made me start wondering about ways to modify the strength of the metal in general, both making it softer, harder, or both.  It's a learning opportunity.

[Daeothar]

Steel can be tempered and/or hardened by adding carbon to the metal when it is being forged. But nothing of the kind can be added afterwards, withour smelting the entire item again.

And such processes are not applicable to the metal used in our miniatures. The alloys used in the old, darker miniatures contained lead, which was desirable due to its low melting point and relative softness, which made for easier conversions and reposings. Plus; it was cheap.

It is also rather toxic in certain circumstances, and fearing that wargaming geeks would cause a second lead poisoning induced burning down of Rome, manufacturers turned to other alloys for their products (also due to legislation here and there).

Most modern miniatures are cast in pewter, which contains tin, zinc, antimony and/or nickle, amongst other metals. These are much harder , but also have a higher melting point than lead.

The alloys are created before casting (in bars/ingots) and their characteristics cannot be changed afterwards.

Using a hot soldering iron or soldering flame will simply melt your miniatures, but the flame will not harden the alloy. If anything, when certain metals are liquified earlier than others, the alloys may actually be weakened, which might lead to brittleness and breakages later on.

Using super glue to strengthen a certain part is a good technique which I've used in the past too. And I suppose paint and varnish will be adding to the strength of the part too. But the only tested and tried method that would offer you the required strength without obscuring surface details (with layers of glue), is pinning the part.

You might have to use a very thin pin and drill bit, but when positioned deep enough into the metal, it will be very effective in strengthening the weak spot...

[warburton]

Agreed, pinning is the only way to strengthen weak joints in metal minis. You can dunk them in boiling water for a bit to soften them so you can bend them if you want to, though I have always have found that any limbs soft enough to bend are bendable at any time, not just after heating.

[YPU]

I'm afraid not. I'm a goldsmith and we work a lot with the kind of alloys daeothar describes, and softening and hardening is something we regularly do. However the only effective way I know of to harden a piece is to apply mechanical stress, either by hammering or stretching it. This stress can then be relieved by heat treating the piece. When the tress is applied the crystalline structure of the piece is stretched and aligned, which hardens the material. When you heat it afterwards at the right temperature those crystalline structures will shift and re-form, releasing the tension in the material.
The crystalline structure of cast models is however already slightly stressed and therefore hardened, since there is a small amount of shrinkage during the cooling. I would however not recommend trying to soften them.

[black hat miniatures]

I would like to point out that the completely lead free story is a myth and a lot of us still cast in a lead/tin alloy for reasons of cost and finish.

Mike

[ErikB]

Wow, thanks for the scientific answers, folks!  I appreciate it.  Good learning experience for me.

My little guy will have to go with a bit of super glue, paint, and varnish to strengthen the little joint.  He'll be fine.

I bet it's frustrating for miniature sculptors to put so much effort into creating these masterpieces (and these Musketeer/Footsore minis are masterpieces) and to have one little design flaw, or one little part that just didn't turn out quite as planned....

[YPU]

Your tpic got me thinking, would there be a market for various blades made in a more sturdy material? I know there are "wire spears" out there for instance.

[Daeothar]

I think so; a variety of swords, spears, halberds etc would go down well with a lot of people, especially since those are usually the most vulnerable parts of a mini (especially when they're regularly put in and taken out of the foam).

What are you thinking of? Doing them in a harder metal? Ideally it would have some spring to it and not be too brittle, as I can imagine pikes or spears not bending but breaking.

I'd say maybe CNC-ing copper or brass (messing) sheet for swords, axes etc and perhaps wire or tubing for the longer weapons like spears and pikes. Maybe with additional weapon heads/tops also cut from sheet metal.

Not everyone would be able to solder them on, but I'm sure most of us could manage. And for those who can't, there's still our old friend superglue...

[YPU]

I was thinking about doing stuff like that and having it cast in messing, since cast its a bit harder then plate.

[Daeothar]

Won't cast brass be more brittle than sheet?

Even though brass is of course many times stronger than pewter or plastic/resin, the problem has always been breakage (usually through repeated bending and rebending), which might be greater with cast rather than sheet brass?

Then again; breaking a brass part through transport foam is admittedly a lot less likely than breaking pewter. And cast weapons can be delighfully 3D as opposed to the flatness of sheet brass...

[YPU]

The type of cast brass I'm familiar with is quite strong. Sturdy enough to function as cloth or ear Pin. In fact with brass copper silver and gold cast material tends to be slightly harder then plate or wire due to shrinkage stress, while plate and wire are anealed to proces them into shape.

[Daeothar]

...brass copper silver and gold cast material tends to be slightly harder then plate or wire due to shrinkage stress...

Yes, but they then are potentially more brittle, although I suppose the expected stresses put on miniatures would be nowhere near the levels required to actually break them...

[ErikB]

Cool!  This could become a side-business for someone.

An idea to throw out there: rigid wire shafts, which already exist (and I need to order more, come to think of it), and then the axe or hammer or whatever weapon heads that the customer puts on him/herself. 

This would require that the weapon heads be molded in such a way that there is a nice dent for the start and the stop of drilling to help the customer get that hole drilled in the right location.  They're tiny pieces so getting that drilled out path right is hard.

Another idea for even more advanced modelers would be having a gutter in the weapon head.  We could use a knife and/or drill to make sure that gutter fits the hard-metal wire and use super-glue and/or putty to cover the gutter, making it smooth.

I would go for that!

[YPU]

Yes, but they then are potentially more brittle, although I suppose the expected stresses put on miniatures would be nowhere near the levels required to actually break them...

My estimate would be that at the sizes of regular wargaming blades (which are out of scale thick) The wrist of a plastic or metal miniature would bend before the blade breaks.

I'm not sure if there is that big a demand for axes or hammers, could you not simply use the plastic one with a metal haft? I know I have done that a few times.

I might try my hand at doing some blades of various sizes and shapes and having them cast as a test batch.

[ErikB]

I remember seeing some brand that made thin blades and guns in 28mm, presumably strong (I didn't feel them), out of sheet metal.  I think it was brass.

The end product, when assembled correctly, looked pretty good.

I think a little bit of liquid putty (green stuff) to fill in the "steps" and light sanding would have rendered excellent looking blades.  Might not even need the putty.

Unfortunately, they were so tiny, I could not imagine being able to keep long blade layers aligned properly, so I did not try them.  Now, I wish I had.

Can anyone recall this company/product?  It may have been a kickstarter.

If we want really, really nice and well-scaled blades, I think this may be a good idea, using a hard wire at the core.  I would love to try them out.