Can you smelt too hot?

[ghh3rd]

I just tried out my Bayou Classic (185,000 BTU) burner with about 1/4 full dutch oven. The ingots were taking very long to cool, and didn't look shiney. Some had cracks and I was able to break them. I just let it all cool off and put it away for another day.

I've been working with a little one burner coleman stove, and this things is like the sun in comparison. It sure melts lead fast!

Randy

[Bigjohn]

Yes!

Sounds to me like they were too hot.

Do you have a lead thermometer?

If not buy one.

John

[ghh3rd]

That will be next on my list. Does it damage the lead if it got too hot?

.

[Ole]

Nothing like lead steam. Yummy! :D

[Bigjohn]

That will be next on my list. Does it damage the lead if it got too hot?

.

IMO; No! You may lose some tin/antinmony from the mix. I have forgotten at what temp. lead fumes output starts to increase.

John

[mooman76]

Also you don't want it too hot because the zink WWs will melt in and you need to discard them.

[jonk]

Well for smelting, I'd say no. Yes you can get it hot enough that the ingots are slower to cool and crack, but part of the cracks I've found is usually because, hot or no, you dump the ingot out too soon. Assuming you have no zinc. If you are outside I wouldn't overly worry about lead fumes either. Even if you get hot enough to turn a tiny bit into a gas odds are any ambient wind- not to mention the blast from your smelter- will drive it away from you. Plus I rather think any lead gas quickly turns to lead dust once away from the heat. Also not nice but at least it will fall.

[HeavyMetal]

Lead fumes start being airbourne at about 900 degrees.

So when smelting or "blending" a large batch of alloy I use a thermometer to keep the temp at about 850. This allows everything to become one alloy and I don't have hard and soft spots.

For plain smelting anywhere between750 and 800 get the job done.

Zinc is much more an issue these days than it has been in the past but I've always spent time "eyeballing" raw materials for the obvious Junk, zinc, trash that one picks up in tire shop ww deals.

Somewhere here I saw a thread where the poster had made his own ingot molds out of angle iron. Think they were 1 1/4 angle about 6 or 7 inchs long with anthor piece of angle welded on each end to make "feet" thing looked neat, Plan to copy it when my current supply of ingots runs low and I need to smelt my WW stash into useable metal.

I mention this because I think you were just dumping your ingots to fast and, at least in my case, thats because you have way more alloy than you do ingot molds!

[OLPDon]

The major importance of keeping the temp below 850 is so if you have zinc ww mixed in they will float to surface and can be removed. Zinc ww in the mix is a no no, that being said.
Keeping the temp down helps speed up the time for the mix to harden up, I have smelted with some high temps with a simmilar results of the same outcome of ingots breaking apart when dumped out of the mould. This was cause by the ingot being much to hot. There was no noticable differance when I cast Boolits with the use of these ingots. I cast Boolits with the temp just up to frost and water drop. My Bhn remains same about 17 Bhn aveg.
I tend to keep my speed of the boolit to middle of the road, as it don't take much to punch a hole in the paper.

To sum it up keep the temp low to keep the nasty Zinc out. My thought is if in doubt through it out. A few Zinc WW will turn your aloy usable for Fishing weights only.
Don

[yodar]

I just tried out my Bayou Classic (185,000 BTU) burner with about 1/4 full dutch oven. The ingots were taking very long to cool, and didn't look shiney. Some had cracks and I was able to break them. I just let it all cool off and put it away for another day.

I've been working with a little one burner coleman stove, and this things is like the sun in comparison. It sure melts lead fast!

Randy

I cast to 600 dF no Hotter. I am running the burner almost dead slow. Running at 600 helps me remove any Zinc and I get nice looking malleable alloy

http://pic20.picturetrail.com:80/VOL1229/6309647/12253703/349433806.jpg

yodar