Annealing

[Mike Dowling]

Does anyone have any experience or know how you can anneal castings ? I am thinking particularly of the metal that goes from the bow of the ship and curves to the hull.

[druxey]

What is the metal that you are trying to anneal?

[wefalck]

Cast metal in most cases does not need to be annealed, because the cooling process is so slow that the metal atoms have time to disorder themselves.

 

Having said that, non-ferrous metals cannot be hardened by heating. Therefore, what you find in a cast piece is usually the softest state. Non-ferrous metals work-harden by beating or rolling. Anealing softens them.

 

I suspect that the cast piece you are referring to is white metal, an alloy containing inter alia lead, zinc, and bismuth. Compared to the pure metals it is quite hard and has a low melting point (which is why it used for such castings). Also, the temperature range for the transition from the solid to the liquid state is quite narrow, so rather than becoming soft as many other metals, it quickly melts.

[Roger Pellett]

When I’m not working on a ship model project, I like to paint lead soldiers.  In this case, “lead” is an all inclusive term for white metal similar to that used in ship model kits. As the kits for these soldiers are produced by small businesses that do not last long, the best source is EBay. This means that the castings range in age from recent to the 1960’s.

 

The older castings have a high lead content and are usually quite ductile; arms, legs, guns, etc. are easily bent without damage.  The newer castings made from Lead Free Pewter are noticeably harder and less ductile.  I would not try to bend these.  I also agree that applying heat is a bad idea.  The melting point of these Pewter alloys can be much less than that of pure lead.

 

Roger