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I'm trying to mix an alloy for casting.

The base metal must be copper and the desired physical properties are

  • melting point as low as possible but below 1000°C (my makeshift crucible won't stand more than 1000°C)
  • silvery appearance, yellow shade is acceptable
  • no excess slag development
  • mechanical properties aren't important

Here's what I investigated so far. My desired material initially was nickel silver (Cu-Ni-Zn) with an approx melting point of 900°C. I had some material which I considered to be nickel silver but I found out it was high grade copper with a thin plating of nickel silver. I have limited access to other materials. I think I have to mix significant amounts of some white metals into it to get brighter colors and lower melting points.

What I have at hand is:

  • several sorts of brass (fittings and pipes)
  • CuNiFe (Pipes)
  • Sn60Pb40 (Solder)
  • Pb60Sn40 (Solder)
  • Ag (brazing solder)

Maybe I can find materials containing higher percentages of nickel or zinc. Special condition: I can't buy any material.

I want to avoid using the Pb contaning solder for health reasons if possible. Maybe there's a CuAg alloy with silverish appearance? How much silver do I have to add? What other alloys are possible?

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  • $\begingroup$ Google search: thoughtco.com/common-copper-alloys-and-their-uses-603710 $\endgroup$
    – Solar Mike
    May 6, 2023 at 8:19
  • $\begingroup$ If the silver outside is for appearance only, consider plating it after it is cast? $\endgroup$
    – Abel
    May 6, 2023 at 11:48
  • $\begingroup$ @SolarMike Nice list. However it neither contains material properties nor percentages of metals. I googled a lot in advance. $\endgroup$
    – Ariser
    May 6, 2023 at 16:24
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    $\begingroup$ Then start with the first one on the list and do more research. $\endgroup$
    – Solar Mike
    May 6, 2023 at 16:50
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    $\begingroup$ Depending on shape you need, you may be able to hot work it instead of going for melt and cast. Could just overcome 1000C in select locations with an oxy-acetalyne torch. $\endgroup$
    – Abel
    May 7, 2023 at 13:33

1 Answer 1

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German silver , as you have found is likely the only practical alloy ( Alloy C 974, 60 Cu, 16 ni, 3 Sn, 16 Zn, 5 Pb). Listed melting temp of 1070 C. You need a higher temperature furnace or , as suggested , try Ni plate.

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