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USSR
11-26-2010, 06:18 PM
Did some rendering of scrap yard lead into ingots today. Things went fine UNTIL, I came to these funny shaped (flat on one side, rounded on the other) ingots with a handwritten "T" on them. When I poured this molten metal into the ingot mould, there was a "bubbling" of sorts as I completed pouring each ingot (the top of the ingot was not perfectly flat as it normally is), the metal took a real long time to get solid in the center of each ingot, and the ingots were quite hard to remove from the mould. A couple of times I tried removing the ingots from the mould when the metal hadn't completely hardened, and the center of the ingot came out, leaving a hole in the rest of the ingot that was still in the mould. The exposed inner metal had a very "granular" appearance to it. Any ideas what I might have here? Thanks.

Don
lwknight
11-26-2010, 10:03 PM
You struck gold!! Its high antimony. Could be babbit or another "type" metal.
Anyway heat it to 650 or so and the bubbly will go away and cast nice smooth ingots.
Give then a lot more time to cool because antimony is a very poor heat conductor.
ince it melts at a low enough temperature to leave the bubbly thick surface its probably at least 5% tin and maybe 15 or more % antimony.
runfiverun
11-27-2010, 02:45 AM
sounds like linotype to me also.
it was called typemetal also.
lwknight
11-27-2010, 02:59 AM
it was called typemetal also.
I knew that. Sometimes I just forget what I know.
Getting older is the pits.
USSR
11-27-2010, 09:25 AM
I've poured a lot of molten linotype/monotype into this ingot mould, and it sure doesn't look or act like that. I don't remember the center of each ingot taking so long to solidify, or the ingots being difficult to remove from the mould.

Don
lwknight
11-27-2010, 12:43 PM
Its most likely very high antimony with too little tin to make a balanced typemetal.
I like to pre mix tin with my rotometals superhard because casting pure superhard does like you described plus the antimony tries to float out if I don't mix tin.
My resulting mix is 9-27-64 and pours just like lino except that there are no wave in the top like lino does.