Stick-on Wheel Weights vs. Clip-on

[I'll Make Mine]

Today I smelted a pot full of stick-on strip wheel weights that I've sorted out from the clip-ons. I'm pretty sure it wasn't my imagination that, with the same flame setting on my stove, the stick-ons started to melt sooner, hence at a lower temperature, than the clip-on style. I had understood that stick-on weights are nearly pure lead (these are very soft, compared to the clip-on), but it wouldn't take much tin to depress the melting point compared to the high antimony, low tin alloy of clip-on weights. Is that what I'm seeing, or was I just fooled by having only about seven pounds in the pot compared with 9+ when I load up with clip-on weights?

[williamwaco]

They also pack closer together in the pot, Thus better heat transfer.
I would expect them to melt quicker.

.

[I'll Make Mine]

They also pack closer together in the pot, Thus better heat transfer.

Aha! That makes perfect sense; the ones on the bottom were in better contact with the pot, too, and once they started to melt, the heat conducted still faster through the melt. I suppose I should start leaving a little "heel" in the pot after smelting, as long as I'm not changing alloys, so the clip-ons can gain a similar advantage.

[williamwaco]

Aha! That makes perfect sense; the ones on the bottom were in better contact with the pot, too, and once they started to melt, the heat conducted still faster through the melt. I suppose I should start leaving a little "heel" in the pot after smelting, as long as I'm not changing alloys, so the clip-ons can gain a similar advantage.

This is such an obvious thing to me that I never think to mention it.

I NEVER allow the pot to get empty. The new pot melts quicker PLUS
Draining the last of the alloy out of the bottom of the pot introduces junk into the spout which interferes with closing the spout and causes leaking.


.

[leadman]

When smelting I leave a couple of inches in the pot.

When casting I follow RCBS recoomendation and also leave a couple inches in the pot. Apparrently this will also extend the life of the heating coil.

[I'll Make Mine]

This is such an obvious thing to me that I never think to mention it.

I NEVER allow the pot to get empty. The new pot melts quicker PLUS
Draining the last of the alloy out of the bottom of the pot introduces junk into the spout which interferes with closing the spout and causes leaking.


.


When smelting I leave a couple of inches in the pot.

When casting I follow RCBS recoomendation and also leave a couple inches in the pot. Apparrently this will also extend the life of the heating coil.

Well, in my case, heating coils and leaking spout aren't an issue; I'm both smelting and casting in old coated iron kitchen pots over a small one burner camp stove. But I did find that a full pot of clip-on weights in the larger smelting pot melted significantly faster today when I started the fill with the heel out of the small casting pot. Big surface area in contact with the pot, faster heat transfer, and once the big slug started to melt, everything else went quicker. I haven't left as much as an inch, but it'll still start the process quicker for the next time -- and when I start with fresh ingots in the small pot, I clearly need to lay at least one flat on the bottom.

[a.squibload]

Propane-tank pot has a curved bottom,
can only ladle out so much. Usually get
about a half inch thick disc leftover.
I stamp the disc from the bottom of
the pot same as the ingots. Next melt
I put the appropriate disc in first.