Federation Commander

mjwest · Posted: Sun Sep 12, 2021 1:16 am Post subject: Unbending Bent Pewter

This is a general question on metal miniatures.

If a pewter miniature has a bent component, what is the best way to "unbend" it? For example, if an F5 boom is bent or a Fed CA engine is bent, what is the best way to make it straight?

Thank you in advance for any advise!
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Sgt_G · Posted: Sun Sep 12, 2021 3:29 am Post subject:

Painted or unpainted??
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Garth L. Getgen

Master Sgt, US Air Force, Retired -- 1981-2007 -- 1W091A

mjwest · Posted: Sun Sep 12, 2021 4:13 am Post subject:

Unpainted, fortunately. So that should make things easier.
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djdood · Posted: Mon Sep 13, 2021 5:51 pm Post subject:

Pewter is not as forgiving as the older lead alloys.

Firm, gentle, pressure over time is the usual prescription.

It can be helpful to have something to clamp the part into - e.x. for correcting bent Klingon booms or Fed engine nacelles, I'll often use one of my small hobby vise-clamps that has channels cut in it to help hold small pipes in place. Those channels also provide a good "jig" to apply pressure to a cylindrical boom or engine evenly.

As long as the bend in the part was introduced after it was cast and it's not too severe, it can usually be set back reasonably straight. (It can never go back to perfect, as inevitably, some of the metal stretched where the bend was).

If the part was always "bent" from when it was cast, then it was probably an issue with differential cooling (or a flawed mold) and is much more difficult to correct without a lot of strong jig-making.
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mjwest · Posted: Mon Sep 13, 2021 10:04 pm Post subject:

This was post-casting. It was a drop, unfortunately.

Does heat help any? Not flame, obviously, but like a blow-dryer or hot sand or some such?
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djdood · Posted: Tue Sep 14, 2021 2:14 am Post subject:

Maybe(?). Honestly, I've never even considered trying it.
You would need a heck of an oven to get it up to the temperature needed and holding on to it would be tricky (and it will be very dangerous until it cools down. Pewter begins to soften at 471 F (becomes fully molten at around 563 F) [per some Googling].

Heat guns, etc. are probably not going to do much to get up to those temperatures.

Usually, pewter will bend, if you go with even pressure and go *slow*. However, it's not nearly as ductile as the lead alloys. It can be adjusted, but not put through kinks like a wire. If you start to hear popping/cracking noises, it's trying to break and is just not able to go where you're pushing it. You also only get one run at it - it essentially has metal fatigue the minute it got bent and you're up against that the whole time.
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djdood · Posted: Tue Sep 14, 2021 2:16 am Post subject:

The bugger with trying to heat it up and soften it will be the same as bending plastic - by the time it's soft enough to manipulate, it's also often soft enough to get marked up or even deformed by whatever tools you are using to hold and deflect it with (unless you've got clamps or a jig that happen to have the right shape, etc.)
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mjwest · Posted: Tue Sep 14, 2021 2:29 am Post subject:

Thanks for the tips!

I'll give it a shot and hope for the best.
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ncrcalamine · Lieutenant Commander Joined: 23 Feb 2010 Posts: 272

have to be careful with heat. I have had figures turn into a puddle as i was straighting them