Mysterious alloy

[Tokarev]

For the gunsmithing purposes I am experimenting with casting aluminum.
As I was looking for the cheap sources of scrap aluminum alloys for casting, I tried everything that looked like cast Al so far and every time made sure that volume density was about correct.
Until I came across a few candlesticks that I picked up for a few pennies at a garage sale.

They appear to be made of silver color alloy, which is heavier than Al but lighter than any other metal I am aware of.
The density is about 5.5 g per cubic centimeter in metric, or 0.2 lb per cubic inch or 346 lb per cubic foot in imperial.
The alloy is soft, but not as soft as pure aluminum.
The candlesticks were painted silver and where I scratched the paint the color of the alloy remains unchanged for a couple years now, pretty much like stainless steel would.

It may be a kind of aluminum-zinc-copper alloy, but much lighter than zinc alloy used for furniture hardware, lapel pins and electronic parts.

Any idea what I have?

[Mk42gunner]

Zamak, aka pot metal?

A lot of intricate stuff that is now made from plastics were cast from zamak in the past. Gears for Atlas lathes were also cast from it.

Robert

[Tokarev]

So it is supposed to melt around 714—734 °F?

[300blk]

Zn MP= 782 f
Sn MP= 449.5 f
Al MP= 1221 f

my guess is an alloy of tin zinc and aluminum with maybe some small % copper.
the tin could lower the overall melting point, in the same way that the melting point of brass is lower than that of copper with the addition of zinc.

This is just my guess, more educated minds may chime in.

[Traffer]

Probably Spelter. Also referred to as pot metal, white metal sh** metal and others. Used very commonly for casting in the past before aluminum casting became economical. Old carburetors for cars were made from it before they went to aluminum.

[popper]

The term pot metal means 'whatever went into the pot' for casting. Triumph used it in their transmission gears. Just cheap low strength metal, usually lots of voids too. Good quality Al alloy is hard to make to any spec. You probably have the 'fake' pewter stuff - only good for ornamental.

[EDG]

I have no idea what you have but if you want to cast aluminum you need an alloy intended for casting. Those alloys are usually loaded with silicon to help the metal flow into the mold cavities when poured.
The simple solution is to buy broken aluminum wheels at a auto salvage yard. Your will get a casting alloy that is probably A356 aluminum that is of decent strength.

Don't treat aluminum like a pot of stew and throw everything into it. Start out with a good metal source. Clean it up and do not mix it.

Aluminum casting alloys and casting technology is a mature industry. It has already been well developed. Just find out what industry already does rather than reinventing the cast aluminum wheel.
Just remember the US govt did not allow us to use aluminum castings in any kind of breech mechanism.





For the gunsmithing purposes I am experimenting with casting aluminum.
As I was looking for the cheap sources of scrap aluminum alloys for casting, I tried everything that looked like cast Al so far and every time made sure that volume density was about correct.
Until I came across a few candlesticks that I picked up for a few pennies at a garage sale.

They appear to be made of silver color alloy, which is heavier than Al but lighter than any other metal I am aware of.
The density is about 5.5 g per cubic centimeter in metric, or 0.2 lb per cubic inch or 346 lb per cubic foot in imperial.
The alloy is soft, but not as soft as pure aluminum.
The candlesticks were painted silver and where I scratched the paint the color of the alloy remains unchanged for a couple years now, pretty much like stainless steel would.

It may be a kind of aluminum-zinc-copper alloy, but much lighter than zinc alloy used for furniture hardware, lapel pins and electronic parts.

Any idea what I have?

[Ballistics in Scotland]

It sounds like some kind of zinc alloy, and probably, due to greater specific gravity, will be a little easier to cast well than aluminium. It will still be a rather unpleasant-looking grey metal, which not many people would care for in gun parts. But there has been a thread on the Casting for Shotguns board in which people got good results casting zinc round balls for cartridge shotguns. Its lower specific gravity than lead permits higher velocities before recoil becomes excessive.