Zinc and heat

[wistlepig1]

After smelting some free WW yesterday I noted a larger amount of Zn WW in my scrape pile. I desided to melt them into ingots for some unknown reason for the future-- maybe fishing Wt.s or "soft hammer head". I got out my BIG Bertha propane tourch and stated to heat the Zn WW's, I was suppized at the amount of heat/time it took. The ones I had would soften alittle and then after lots of heat finaly would melt. I am not sure what the rating is on this tourch but I know it will melt lead real fast.

I was wondering with the Zn's floating on top of a melt at any temp. that isn't very high for a long period, How does Zn get into a lead mix. In a pot it must take a long time, maybe 20-30 min.'s at high temp to get this Zn to melt into your lead or a real hot "turkey Cooker". Am I all wrong on this, as this was my first time melting Zn WW's or is there something that I missed. Thanks for setting me right I my current view.

[cbrick]

Zinc melts at 787 degrees. Antimony melts at 1167 degrees but it melts right into your alloy at a much lower temp. In the liquid alloy your zinc will melt right into the alloy even quicker than does antimony if you don't remove it quickly.

Or look at it in reverse, tin melts at 429 degrees and lowers the melting temp of lead.

Rick

[sagacious]

How does Zn get into a lead mix. In a pot it must take a long time, maybe 20-30 min.'s at high temp
Some folks will just crank up the heat fit to melt the hinges of Hell, and let it soak for a good long time. That can do it.

Also, on a pot full of unmelted ww's, the bottom of the pot gets very hot as there is no heat sink yet. The temp at the very bottom can get higher than one might think. If you have a few zinc ww's at the bottom, they can melt. This can catch even careful folks off-guard.

[lwknight]

Definately take your time getting the melt started. Once you get liquid in the bottom , you can let er roar.

[qajaq59]

I usually leave about a 1/4 inch of metal on the bottom of the pot as a starter for the next melt. It seems to speed the initial melting a bit.

[jr81452]

Also, on a pot full of unmelted ww's, the bottom of the pot gets very hot as there is no heat sink yet. The temp at the very bottom can get higher than one might think. If you have a few zinc ww's at the bottom, they can melt. This can catch even careful folks off-guard.

This! The bottom of your pot can easily reach in excess of 900deg when you are starting out a melt. If zinc is trapped at the bottom, ti will surly melt. For this reason, one should ether leave 3/8" or more melt in the bottom for the next session (a large amount to waste if you have a big pot) or only put in known good lead until you have enough melt to check the temp.