Linotype smelting -- first time question

[h8dirt]

First -- I smelted about 40 pounds of linotype this weekend from old type-set that I found. An old, clean cast iron dutch oven was used as my melting pot and I used a standard S/S soup ladle for pouring. Also, I used pine sawdust with a little motor oil for flux and I used mini-muffin tins for molds. The pours looked clean and the surface of the molten lino' was bright and free of debris and dross. Each ingot weighed out at 8 oz +/-. All good.

The question -- about half of the ingots had surface porosity and a rough finish. The same tin (with 12 molds) was used multiple times. Each batch was similar. Could the surface irregularity be from a coating that may have been on the muffin tins? Any ideas?

[Larry Gibson]

If that was the sides and bottom of the ingots it simply means the muffin tins were cold and/or there was moisture (oil probably) seeping out. The high antimony content of linotype that is not in solution with the lead is the most likely cause. as it solidifies separate from the lead/antimony/tin that is in solution. Nothing to be concerned about. For a very good alloy with linotype I add the same weight of lead and then add 2% tin. Pretty close to #2 alloy that way. For a higher velocity rifle bullet I only add 20 -30 % lead and AC the bullets for about 18 - 20 BHN after 10 days and a lot more malleable (less brittle) bullet.

Larry Gibson

[bangerjim]

Larry's right on.

I pour a lot of lino and see the same thing. No degradation in the alloy that I have ever seen. I have found that using the Lee aluminum molds works better than CI on many alloys for temp reasons. The Al heats faster and gives a much better/smoother finish on the bottoms/sides and I do not see as much top surface "crystals/roughness".

bangerjim :guntootsmiley: