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"Do they know about shrinkage Jerry?" Topic


14 Posts

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1,421 hits since 2 Oct 2021
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Comments or corrections?

The Tyn Man02 Oct 2021 6:30 a.m. PST

A manufacture told me years ago, that when you make a mold and cast a figure, there is some "shrinkage" between the original fig and the newly cast one.

So, can any tell me how much shrinkage there is? Like if you want to cast a 15mm fig, would you make the sculpture 16mm?

Cheers
Dean

Thresher0102 Oct 2021 7:20 a.m. PST

That is true.

IIRC, the is usually about 3%, or so (can vary from 2% – 4% I think).

Then of course, there's the whole 15mm/18mm scale creep issue too, so……………

Master Caster02 Oct 2021 7:51 a.m. PST

It is very true about shrinkage being a factor, but more so on a vertical plane where the mold halves meet. Speaking about and planning for figures, the height of the figure is only affected minimally – if at all – and no set reduction percentage, but rather the thickness of the torso of the figure can greatly be affected as much as 10% or more, sometimes less depending on the grade of the rubber and the alloy used in casting.
For large figures, the shrinkage factor can really show up more prominently in the legs.
Toby Barrett

Stryderg02 Oct 2021 8:10 a.m. PST

I would think that it would depend on the materials used. But I'm not a metal caster, so that's just a guess.

Personal logo StoneMtnMinis Supporting Member of TMP02 Oct 2021 9:37 a.m. PST

Also,
depends upon the mold material. Some materials give minimal shrikage, but offset that by have a short production life.

Black rubber, used for the majority of production molds, has the greatest shrinkage, but offsets that with a longer production life. This makes black rubber the most economical for companies to use as constant mold replacement is expensive and time consuming.

skipper John02 Oct 2021 9:54 a.m. PST

Is it legal to recast figures?

I have a bunch of the Scheltrum Ming castings that are about 30mm (sold as 28's) and at 3-4% shrinkage it would make them a perfect match to my Perry Koreans. Also, Scheltrum is out of business. Sounds like the perfect solution to my problem!!

Stryderg02 Oct 2021 11:09 a.m. PST

No, but knock yourself out.
<tries to close a recently opened can of worms>

SHaT198402 Oct 2021 11:49 a.m. PST

Is it legal to recast figures?

Not wrong, if you are making for your own use.
I've done mine to patch ranges that didn't cater for campaign dress very well.

It would only be illegal if you intend/ do to sell them, then watch you back…

Thresher0102 Oct 2021 11:54 a.m. PST

The issue for where the "vertical" shrinkage occurs due to the pressure used to hold the molds together, I suspect.

I have seen some very flat figures due to that from some manufacturers. I imagine too much pressure was applied to the plates holding those together while spincasting, causing the issue.

Personal logo Virtualscratchbuilder Supporting Member of TMP Fezian02 Oct 2021 12:33 p.m. PST

Is it legal to recast figures?

Not wrong, if you are making for your own use.

picture

mildbill02 Oct 2021 1:34 p.m. PST

I believe the number is 300 figures.

The Tyn Man02 Oct 2021 1:57 p.m. PST

Thanks very much for all the replies, and Master Caster that's the info I was looking for.

Cheers
Dean

PS I'm planning to sculpt some figures, not recast others.

clibinarium02 Oct 2021 4:03 p.m. PST

Recasting is significantly worse than Regifting. Only a Scofflaw would consider it.

Master Caster03 Oct 2021 7:51 a.m. PST

Tyn Man,
Antimony – if used as a small percentage (say less than 5%) in a casting alloy – can help lessen the shrinkage factor in figures and items cast for sale. Antimony is a metalloid vs a metal and expands a bit as it cools. True metals shrink as they cool.
It also tends to lower the melting point of the alloy so antimony is not good in an alloy used for production models used to vulcanize molds.
Toby Barrett

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