Un-melting Muffins

[jonp]

I have about 100lbs each of COWW and Core Lead I melted down into corncobs. I bought a box of muffins from a guy here that were supposed to be pure or nearly pure lead and I can scratch them with my fingernail.

The thing is that when I was mixing 50/50 last 2 weeks ago and again last week the COWW melted right off, the core lead melted right off but some of the muffins would not melt for some time. They all melted in the end but I am a little stumped.

Any ideas on this? They do not appear to be Tin and as I said I can scratch them with my fingernail.

[gtgeorge]

Pure lead has a higher melt temp and if I understand you correctly the first batch of "core " lead must have contained tin and/or antimony if they melted at a lower temp along with the COWW. The pure lead would be the last to melt.

[bumpo628]

Melting points vary according to the alloy and they are typically lower than pure lead by itself.
What you described sounds normal.

Here is an example from one of the stickys in this forum:
621° = lead
563° = solder (10% tin & 90% lead)
529° = solder (20% tin & 80% lead)
504° = solder (30% tin & 70% lead)
464° = solder (40% tin & 60% lead)
428° = solder (50% tin & 50% lead)
374° = solder (60% tin & 40% lead)
362° = solder (63% tin & 37% lead) (eutectic)
365° = solder (70% tin & 30% lead)
392° = solder (80% tin & 20% lead)
421° = solder (90% tin & 10% lead)
450° = tin

[sqlbullet]

Also keep in mind that pure lead melts like an ice cube. Solid, then liquid, no slushy in between. You alloys, in addition to melting at a much lower temp, get soft, crumbly, mushy, oatmealy, then liquid.

[plainsman456]

Put the muffins in first.:grin:

[jonp]

Thanks for the answers. I had thought the core lead was pure enough to melt at the same time as the muffins but guess not.

[dtknowles]

Since you were melting this all together, I would think this is good news your new alloy will have more Sn or Sb than you were expecting.

Tim

[jonp]

I was going for a 50/50 but it dosnt bother me in the least. I was just scratching my head a little. A little Extra tin is not a bad thing!