4000lbs lead keel

[SandRoad]

You might want to test the lead first, take some and cast it.

Very often, lead keels were, and still are, made with scrap and reclaimed lead, and the alloys could be anything, including a fair amount of zinc. Basically the cheapest #### lead they can find. Makes no difference casting a keel, but if you are trying to fill out a small precision mould......

Some metals warehouses sell bulk casting lead for things like keels. It's reclaimed, bulk melted/smelted and completely unrefined, unknown composition, but also the cheapest.

You could get lucky and get really nice alloy or stuck with something that doesn't cast worth a damn.

 

[yomomma]

The boys over at castboolits have that covered. They even have a way to get zinc out of the mix.

 

[ted_dent]

They even have a way to get zinc out of the mix.

Can you give a thumbnail summary of how they do it?

 

[SandRoad]

Can you give a thumbnail summary of how they do it?

Mixing sulphur into the molten lead. Note that this is mixing (lots of sulphur) not fluxing. The sulphur has to come in contact with all the molten lead.

The sulphur reacts with the zinc and forms zinc sulfites. The sulphur also reacts with tin and lead, but much slower. The cake containing sulphur and sulfites is then removed from the top, or lead drained from the bottom (better).

Do it outside, away from everything because the sulphur fumes will travel for miles and permeate everything it touches for a long time.

Melting Point: 112.8 °C (235 °F)
Boiling Point: 444.6 °C (832 °F)

 

[ted_dent]

Mixing sulphur into the molten lead. Note that this is mixing (lots of sulphur) not fluxing. The sulphur has to come in contact with all the molten lead.

The sulphur reacts with the zinc and forms zinc sulfites. The sulphur also reacts with tin and lead, but much slower. The cake containing sulphur and sulfites is then removed from the top, or lead drained from the bottom (better).

Do it outside, away from everything because the sulphur fumes will travel for miles and permeate everything it touches for a long time.

Melting Point: 112.8 °C (235 °F)
Boiling Point: 444.6 °C (832 °F)

Thanks.

 

[yomomma]

People forget that up to 3% zinc in the mix is not actually a bad thing

 

[ted_dent]

People forget that up to 3% zinc in the mix is not actually a bad thing

Considering that most people seem to consider zinc the antichrist of bullet casting I'm surprised to hear this. 3% is actually a substantial component percentage considering that lead typically makes up around 90% of most alloys, leaving only around 10% total for everything else (tin, arsenic, antimony, etc.). If this is accurate it doesn't hurt my feelings as I'm sure I've accidentally mixed in a few zinc wheel weights when smelting down my bulk lead into casting ingots & always worried it would contaminate the whole lot.