How to keep dutch oven consistent temperature when smelting?

[theTastyCat]

Did my fourth smelt today. Finally had a 12" China Freight dutch oven so I was all pumped. I loaded that sucker full of WWs and sawdust and set the fryer on nuclear. When it had melted down some but no molten lead yet visible I loaded it up again.

When I started pulling dross out, it was almost coated in the oatmealy layer I have seen and read about here. I knew I was pulling lots of lead out with the dross, and it would make sense that zinc could be the culprit. Clearly, the bottom layer of a full 12" dutch oven would get way hotter than the melting point of zinc before the top layer would be warm enough to melt. So, I made ingots and put it in the "might be zinc" pile for when I want to do the sulphur thing.

So I began filling the dutch oven halfway and applying much less heat, and turning it almost off at the first sign of molten lead. This worked much better - I got dross that contained almost no lead at all, but the next batch started getting coated a bit again. Here's a photo - does this look like zinc contamination to you?

http://i930.photobucket.com/albums/ad145/thetastycat/zincsmelt.jpg

It did kinda stick metal to everything - the slotted spoon, the clips, everything.

So I need to get my replacement thermometer back from TelTru so I can tell what the heck is going on, but what do you all do to smelt in a 12" dutch oven? I'm trying to avoid sorting all the zinc and iron out of my WWs as I've got a lot, but if that's the only way to prevent contamination, I guess I have to. I was really hoping to load up a dutch oven, nuke it, and have a nice lake of molten lead - I guess nothing's easy! I think my latest idea of trying to keep the melt as low temp as possible (just enough to melt the lead) might be the smartest, but dang, it takes a really long time! I really hope there's a better way.

Thanks for sharing your experience - can't tell you how much I appreciate the spirit and knowledge of this forum.

[*Paladin*]

Flux and stir while the clips are still in the pot. The flux will "pull" the lead off the clips. Then skim the clips out. Once the clips are out, I flux one more time and skim off the remaining dross and pour.

[theTastyCat]

Yeah, I've been putting sawdust in as I fill the pot with WW so it's really in the middle of things - the problem is that there's nothing to stir when only the very bottom is molten and the top is untouched. I think I may just have to put about a half-load in the oven and keep the temp low. But other than that, I do the same routine as you - having the sawdust in between the WW helps it flux as it melts, though it makes it hecka smoky, but that's probably because the sawdust I was using was pretty hecka wet! Live and learn.

[bumpo628]

Let it melt, then flux...with dry sawdust.
Start the melt with large, obviously lead, wheel weights. After you have it going, you can put all the small and questionable weights in there. Watch the temps. That will help you minimize zinc contamination.

[*Paladin*]

I've never used sawdust, but parafin wax for flux and the clips will come out clean...

[44fanatic]

Dang, If I knew you were smelting today I could have dropped by. Spent the day on the range at Cheatam WMA. Last two times I was out there, ran into booliteers who were willing to share what they had learned, gotta pass it on sometime.

Keep your heat low and work up from there. Once you get your thermometer back, keep it below 700 for smelting, dont turn the heat down once it reaches 700, turn it down before hand.

[lwknight]

The blob of wax ( not sawdust ) will cause the junk to release the lead.
To get clips and other junk out clean you need a few seconds of liquid flux in the pot.

And I agree that melting in nuclear reactor mode will get you some melted zinc. Take your time
and melt slowly unless you absolutly know that you have no zinc.

[DukeInFlorida]

Why is everyone always in a hurry when they smelt???

Don't get the flames up so darn high when you smelt. And, don't start off with a FULL pot of raw ww metal either.

In fact, the safest way (in my humble opinion) to do it right, is to put a couple of already smelted WW ingots in the dutch oven, and put the heat on those, until they melt completely.

Then, add a couple handfuls of raw ww's to that, and stir and skim. Add a bit more. Stir and skim. Takes a short time to build up enough to start doing the fluxing routine. Get your metal good and clean, and ladle off some metal. However, don't empty the pot. Leave enough in there, and start building up the volume again, like you did at the beginning. Repeat until you are out of metal. Then, leave a 1/2" thick layer of ww metal in the bottom of the dutch oven, for the next time you'll use it. Use that to get you started.

For me, it's not at all about speed. It's about quality. And, with more and more zinc weights coming along every day, it's critical to go slow and careful when smelting.

Hope my technique helps you.

[WILCO]

but dang, it takes a really long time! I really hope there's a better way.

Sounds like your problem is temperature. Large quantities of lead take time to smelt. Just like anything else "heat" related, start out with a small amount and build up from there. Pay attention to your flame, block out the wind and leave the lid on the dutch oven. The bulk of my smelting has been done on a smaller scale with a hotplate, chinese skillet and a homemade lid.

[jmsj]

Why is everyone always in a hurry when they smelt???

Don't get the flames up so darn high when you smelt. And, don't start off with a FULL pot of raw ww metal either.

In fact, the safest way (in my humble opinion) to do it right, is to put a couple of already smelted WW ingots in the dutch oven, and put the heat on those, until they melt completely.

Then, add a couple handfuls of raw ww's to that, and stir and skim. Add a bit more. Stir and skim. Takes a short time to build up enough to start doing the fluxing routine. Get your metal good and clean, and ladle off some metal. However, don't empty the pot. Leave enough in there, and start building up the volume again, like you did at the beginning. Repeat until you are out of metal. Then, leave a 1/2" thick layer of ww metal in the bottom of the dutch oven, for the next time you'll use it. Use that to get you started.

For me, it's not at all about speed. It's about quality. And, with more and more zinc weights coming along every day, it's critical to go slow and careful when smelting.

Hope my technique helps you.

Well said Duke.
I too was in a hurry when I started smelting. I read stories of guys doing thousands of pounds in a day. They have way more talent and lead than I have. It only took me one time of contaminating my lead w/zinc to slow down.
Once the lead is melted, it takes little heat to keep it liquid. As the lead level in the pot goes down the tempature will go up. I keep an eye the tempature and adjust the flame down as the lead level goes down. A cooler smelt tempature helps keep your tin from oxidizing(have you seen the price of tin lately) and lets your ingots harden faster so you can pour and dump your ingots faster.
Good luck, jmsj

[zomby woof]

Flux and stir while the clips are still in the pot. The flux will "pull" the lead off the clips. Then skim the clips out. Once the clips are out, I flux one more time and skim off the remaining dross and pour.

This is what I do

[Charlie Two Tracks]

Remember that the wax is going to ignite. It might surprise you if you don't light it up yourself. Be very careful adding lead to a melted pot. I fill my cast dutch oven to overflowing, slowly bring the heat up and once it starts to melt down, I stir it until it is all melted. It will take me a half hour to get it up to temperature. Once it is all melted, I put a bunch of sawdust on top, ignite the sawdust and let it burn to black ash. I then stir it in. I used motor oil once but did not like the soot that it left in the lead. You will find your way of smelting but be careful.

[lwknight]

All good advice. It looks like we got it pretty well covered.

[Charlie Two Tracks]

I FORGOT! Don't lift that pot with melted lead in it. First time I smelted, I started to lift the cast pot with the handle and nearly spilled the whole thing. Molten lead behaves differently than water.