Casting Gunmetal

[ron vale 3Participant @ronvale3]

 

 

I have about 1.5kg of gunmetal swarf etc which i want tp melt and cast back as small bars 30x50x15mm bar to machine bearing shells for the main axles

Has anyone done this at home, or got the local foundry to do it?

[noel shelleyParticipant @noelshelley55608]

YES ! I have done it Ron. What also makes good stock is marine water pumps. Do you already have all the gear to do this ? Send me a PM and I will give you my contact details.  Noel.

[Nigel Graham 2Participant @nigelgraham2]

A commercial foundry is very unlikely to do that unless you brought an entire furnace-charge. 1.5kg is not much metal at all, by their standards.

That is because they have ensure the alloys they use, particularly if their trade customers need particular specifications verifiable by audit.

So although they might be able to melt that lot as one charge, they don’t want to risk contaminating their primary work. You could ask if they will sell you cast bars of new metal partially discounted by trading-in your swarf as scrap to add to their own (the cut-off runners and gates) they sell back for refining.

 

The brasses and bronzes can be melted and cast in a home foundry, as proven by some model-engineers, but I have never tried this.

 

Not much at all…

1.5kg of gun-metal at 8720kg/m^3.

If my rusty arithmetic is correct that will yield just seven-and-a-half of those blocks, neglecting furnace and mould-runner losses (or using an open mould). Account for the losses and you likely won’t have enough.

A piffling volume for a commercial foundry having to melt and cast the metal sequestered from the rest.

More economical to cast just one, or perhaps two bars, you can saw to length.

Even if you find a willing foundry it may be cheaper to buy stock bar. Or to use cast-iron or mild-steel axle-boxes with bronze liners rather than solid, unless they will be visible and need copy the prototype. Cast-iron is a good bearing metal itself for a mild-steel shaft.

 

[old martParticipant @oldmart]

You should be able to heat it enough for simple casting, but try not to breathe the fumes as many gunmetals contain lead.

[noel shelleyParticipant @noelshelley55608]

As feed stock swarf being finely divided will invite oxygen absorption – but there are techniques to reduce or prevent this. There will be losses but one might hope to get 50% recovery. Noel.

[Author]

Posts