Is it tin?

[Avery Arms]

I purchased an old plumbers pot full of alloy, it had been used for casting bullets and the seller said the alloy was 50-50 tin/lead.

But before I start calculating how much to add to my casting pot how can I be sure I actually have 50/50 and not 70/30 or wheel weights or linotype or????


PP

[sqlbullet]

The melting point for lead/tin allows should be 361.4° F.

Sources conflict if this is a constant or variable. Wikipedia states all lead tin alloys melt at this temp, while other sources indicate it varies, becoming lower as the amount of tin increases. I believe any significant percentage (say > 5%) of tin in a pure lead/tin alloy will cause the melting point referenced above.

If it requires a significantly higher temp to melt (+50°) then it has some other metal(s), which would indicate monotype, linotype, wheel weights, etc. These all melt between 450° F and 510°F. Other lead/tin/antimony allows vary depending on ratios, but rarely dip below 450° F based on my reading.

This should help determine if there are other metals present, but will not help ascertain the actual lead:tin ratio if those are the only metals present. Tensile strength tests come to mind, but such are not readily reproduced, at least in my garage.

[fourarmed]

This was posted earlier on another thread. The specific gravity of an alloy consisting of equal parts by weight of tin and lead should be about 8.9.

Weigh a chunk of the alloy. Then put a container of water on the scale and weigh it. Now tie a string to the chunk and lower it into the water until it is just submerged. Weigh the container again. The difference in the last two weights is the buoyant force of the water on the chunk. The weight of the chunk divided by the buoyant force is the specific gravity.

[sqlbullet]

Good call on specific gravity fourarmed...That is what I get for not cracking an engineering book in the last 15 years.