Hot plates for smelting

[sirAIG]

Hey all,

I am a newb to casting - I smelted down ~25lbs of range lead this past weekend and found out quickly that i could not get my propane heater down to a low enough temperature to keep from seperating the tin/antimony and getting the gold/blue death on the top of the pot. I will get getting a bottom pour pot for actual casting, but have ~100# more of range lead to smelt into ingots and want to work at understanding what I am doing wrong better before casting bullets. My question to you all - Is anyone out there using hot plates to smelt lead itself? I know cheap ones are used for keeping molds in proper temp range. I just feel as if a hot plate would be much easier, and cheaper in the long run for smelting. As i can get a consistent temperature and no use of propane. If no body is using hot plates, might i ask why? Does anyone know of any hot plates that can reach the desired temperature that dont cost an arm and a leg.

Thanks,
Aaron

[captaint]

Not many of us are using hot plates for smelting because it slows us down so much. Takes WAY too long. You don't have to spend a bundle, though, to do it right. I got a fish fryer from Wally's - about 35 bux. Got a cast iron 8 qt dutch oven from Harbor Freight - about 20 bux. Get a propane bottle and you're in high cotton. Much faster AND better all around. Mike

[shadowcaster]

What type of propane heater are you using? All of the ones I have seen you can turn down to a very minimal flame making the heat control very easy. Hot plates are real slow for smelting, unless you only have a small batch to do. They are best served as mold and ingot heaters.

Shad

[ku4hx]

I used a hot plate for years, but for me it definitely was a small batch operation. Then I found an old propane fish cooker I'd forgotten about. Being able to mix 30-40 pounds of alloy at a time surely made the process a lot easier. I could double that weight, but 30-40 is enough alloy for me to stir and dip at one time.

As far as cost, you're going to have to be a bit more specific. An arm and a leg for me (and others) is probably quite different than an A&L for you.

[Springfield]

In my experience the Gold/blue on top of the lead just means you have a very soft mix, my pure lead does that. If the mix is getting too hot then you are leaving it on the heat to long. As soon as it melts and looks good dipper it out. I know my hotplate would probably never melt any decent amount of WW. I used to use a Coleman stove but now I use 2 turkey fryers for my big batches, and the propane has always worked very well. What kind of propane melter are you using that gets so hot?

[375RUGER]

My preference is to use a wood fire to melt my range lead, a lot quicker than the propane burner. I can do about 130# in one shot in a cut off Freon tank. Once I remove all the jackets and rocks I flux it a couple times real good and ladle it out into the ingot molds.
Are you fluxing?

[Marlin Junky]

Hey all,

I am a newb to casting - I smelted down ~25lbs of range lead this past weekend and found out quickly that i could not get my propane heater down to a low enough temperature to keep from seperating the tin/antimony and getting the gold/blue death on the top of the pot...

Thanks,
Aaron

Where the heck are you getting your information? Those are just color phases that any shinny metal goes through between about 450F and 600F. It just happens that Pb alloys are molten in this temp range.

MJ

P.S.

Here ya go...

Notice at 630F, the color is fading to gray? At normal casting temp's (650F-750F) the color is gray so there's no discernible color cast when your alloy is at the proper operating temperature.

[williamwaco]

Marlin,

I don't understand the right side of that chart.

When I fire up my pot, when it is half full of any normal bullet alloy, the metal is grey - silver/grey and it never changes within any normal casting temperature.

When I get distracted and let it cook for 30 or 45 minutes it might get a purple / blue / gold film on top but that is only on top. The alloy is still silver/grey under the film.

I do note the colorful film is much more prevalent on pure lead.

Maybe I am just color blind?

Do you really see those colors in your pot?

[sirAIG]

Information found >http://www.shotgunworld.com/bbs/viewtopic.php?f=13&t=189902

And one other link with a write-up that seemed to contain lots of valuable information. Will see if i can dig it up.

[sirAIG]

Marlin,

I don't understand the right side of that chart.

When I fire up my pot, when it is half full of any normal bullet alloy, the metal is grey - silver/grey and it never changes within any normal casting temperature.

When I get distracted and let it cook for 30 or 45 minutes it might get a purple / blue / gold film on top but that is only on top. The alloy is still silver/grey under the film.

I do note the colorful film is much more prevalent on pure lead.

Maybe I am just color blind?

Do you really see those colors in your pot?

This is what i am seeing. And i am assuming that most of my lead is pure due to it being 99% jacketed bullets. From the little i have read, they dont mix anything with the lead in jacketed bullets. Still really new to all of this so please feel free to interject.

[shadowcaster]

This is what i am seeing. And i am assuming that most of my lead is pure due to it being 99% jacketed bullets. From the little i have read, they dont mix anything with the lead in jacketed bullets. Still really new to all of this so please feel free to interject.

I wouldn't assume anything with range scrap. I too hear some say that it should be almost pure, but all the range scrap I have dealt with comes in from 12 to 15 bhn and it's all from jacketed. I have tested many samples from different batches. In fact.. sometimes I can see on the pieces where many jacketed bullets have smashed together and the lead actually sparkles. This scrap definitely has antimony in it.

Do you use a thermometer? This will tell you if you are getting to hot. Some don't, but I use one every time.

Shad

[sirAIG]

Now that i have more time...

I am using a propane cooker my father made years ago to frying big batches of wings. It has a ball valve on it that can control the flame - but as i said, i am still very new at this. I probably need more experience. I cranked it up hard and realized that everything was actually melted and it was just so full of jackets that i didnt realized, so i skimmed jackets off and turned heat back a lot. I fluxed with sawdust from my table saw a few times. then i started getting an almost instant gold skim on the top... if i let it sit for a few minutes it turned blueish. almost black. i fluxed quite a few more times thinking maybe it was some junk i didnt want. ended up saying the hell with it and poured it all out into ingots and did a little homework i probably should have done before. That is what lead me to the conclusion i had the melt too hot. But i am unsure if this is true or not. My issue is that for the time being, i am going to be using a dipper to cast my bullets. I think that crud on the top would be no-good for molding bullets. but maybe i am completely wrong. Any insight is greatly appreciated.

[glw]

I currently use hot plates to smelt (and to mold, for that matter), since that is what I have and is what I can afford right now. It is slow, but it does work. I did have to modify the switch so that it doesn't cut off the electricity, which kept the lead from melting. I use some cast iron pots that were given to me. They hold about 7 or 8 pounds.

Glenn

[OnceFired]

I used a hot plate I bought from Walgreens. It was utter garbage. The auto-shutoff function of the plate prevented steady heat for more than a couple minutes, at most. It was awful. Lead cools & hardens very quickly, especially if you are monitoring the temp to prevent Zinc melt.

I switched over to a turkey fryer & steel pot. Works great.

ZAG

[375RUGER]

A batch of range scrap that I had analyzed was Sn .4% Sb 2.3% Bi 3%. I treat it as 5% Sb for all practical purposes. I have a good mix of j-words and boolits, I'd say 50/50.
I forgot to mention that when I flux it is fairly hot 850* but at that time my fire is low and the batch is starting to cool down. Buy the time I do a second or third flux, it's down in the low to mid -700 range and that's when I pour. I think it fluxes better over 800*. I sometimes don't even flux when I remelt it and am ready to pour, but when I do I use Marvalux (sp)because it's low smoke even though my shed is ventilated with a 6" squirrel cage and duct.
I ladle pour some boolits and bottom pour some. I modified the thermostat on my hot plate so it would hold proper temp for ladle pouring.

[Marlin Junky]

This is what i am seeing. And i am assuming that most of my lead is pure due to it being 99% jacketed bullets. From the little i have read, they dont mix anything with the lead in jacketed bullets. Still really new to all of this so please feel free to interject.

Are you getting all your information from the Internet? Perhaps you should experiment in the ancient form of information exchange otherwise known as printing.

Jacketed rifle bullets can contain 2 to 3 or more times the amount of antimony contained in jacketed pistol bullets.

MJ

[Marlin Junky]

Marlin,

Do you really see those colors in your pot?

Sure... I normally do not watch my pot heat up but when I do notice the phase change, (from solid to liquid) there's always a color shift from amber to purple to blue to gray on the surface. However, I flux and skim the dross to create a smooth, relatively oxide-free surface at the end of my casting session (and the beginning), turn off the power and unplug the pot allowing the surface to freeze smooth and relatively clean.

MJ

P.S. To answer the original question about smelting (I'll get to that misnomer in a second) on a hot plate, I haven't found a hot plate to date that'll achieve much more than about 550F. In addition, it would not be a very efficient method of RENDERING ingots from scrap Pb alloys.

I've noticed that many here substitute the term "smelting" for "rendering" when producing ingots from scrap Pb alloys and tin and perhaps even a bit of other metals such as Cu; however, smelting is actually defined as extracting metal from ore. So, if you are actually smelting lead (Pb), you may receive a visit from OSHA some day.

[williamwaco]

Sure... I normally do not watch my pot heat up but when I do notice the phase change, (from solid to liquid) there's always a color shift from amber to purple to blue to gray on the surface. However, I flux and skim the dross to create a smooth, relatively oxide-free surface at the end of my casting session (and the beginning), turn off the power and unplug the pot allowing the surface to freeze smooth and relatively clean.

MJ

P.S. To answer the original question about smelting (I'll get to that misnomer in a second) on a hot plate, I haven't found a hot plate to date that'll achieve much more than about 550F. In addition, it would not be a very efficient method of RENDERING ingots from scrap Pb alloys.

I've noticed that many here substitute the term "smelting" for "rendering" when producing ingots from scrap Pb alloys and tin and perhaps even a bit of other metals such as Cu; however, smelting is actually defined as extracting metal from ore. So, if you are actually smelting lead (Pb), you may receive a visit from OSHA some day.

I never did like the "smelting" verb either. I just didn't think of a better alternative.

Next time I fire up the pot, I am going to watch it very close for those colors.

[b2948kevin]

Just get a bottom spout pot and you'll be in good shape. Also, you'll see on here if you research that the colors that you're seeing at high temps is a result of oxidation. A little sawdust or similar on the top of your melt will reduce the air contact and solve some of this. I don't think it's as big a deal as some.

[Marlin Junky]

Just get a bottom spout pot and you'll be in good shape. Also, you'll see on here if you research that the colors that you're seeing at high temps is a result of oxidation. A little sawdust or similar on the top of your melt will reduce the air contact and solve some of this. I don't think it's as big a deal as some.

Nothing is a big deal once you understand.

The colors will disappear once the surface oxidizes, or (before oxidation occurs) the surface of the melt exceeds approx. 640F... whichever occurs first. As you can see from the color chart above, the color cast begins at about 400F, but you won't notice it if your melt is "crusted over" with oxides.

MJ

P.S. And... if you are just starting out on your boolit casting adventure, I don't recommend a cheap bottom pouring furnace for anything except preheating alloy for a quality bottom pouring furnace. Better yet and for less money would be a nat-gas powered unit with a large cast iron sauce pan (with lid), an RCBS thermometer and a Rowell ladle. I prefer the Rowell#2 but a #1 works well for most 2-4 cavity molds. Personally, I would never use any bottom pouring furnace to cast precision rifle boolits .25 caliber or larger.

[sirAIG]

can i ask what a quality bottom pouring furnace would be? I see tons of people using the lee's. What is really wrong with them?.

[Marlin Junky]

can i ask what a quality bottom pouring furnace would be?

One with a very deep reservoir to maintain head pressure for at least a couple hundred casts, wide adjustable diameter spout and a shut off valve that doesn't leak. Perhaps a Magma for 3-4 clams.


I see tons of people using the lee's. What is really wrong with them?.

I see "tons of people" in McDonald's drive through lines too... that doesn't make McDonald's food healthy.

Buy a Lee furnace and try it out... you may find it entirely adequate as long as you're not trying to cast long range rifle boolits with it.

MJ

[mrblue]

Search around on the forums and you will see people complaining alot about the lee pots and how they drip. I have one, yes it drips, and Ive cleaned it before. But i can live with a little drip. For the price you cant beat it.

[sirAIG]

I'm not too worried about a little drippy drippy. I don't have any intentions on casting long range rifle boolits. Just 9mm, 40sw, and 45acp to satisfy my pistol shooting addiction thanks for the information. I melted down some more range lead last night and was still have issues even running the pot hotter. Have a lot of oxidation on the surface of my ingots. Fluxed tons and monitored the temp at around 650-700 deg. Unsure what else I need to do beyond picking up some books and reading. Which I currently do not have access to.

[DeanWinchester]

I used a hot plate for years for smelting and casting. They burn out in six months with heavy use but you can get one for less than $20 so that's what I used. Then I got Lyman pot and have never been happier. Then I got a turkey fryer for smelting and now I feel like a fool for all the time I wasted.

[375RUGER]

Have a lot of oxidation on the surface of my ingots.

You may be seeing frosting on your ingots from the Sb. Don't worry about the appearance of your ingots except for excessive inclusions of foreign material.

[shadowcaster]

can i ask what a quality bottom pouring furnace would be? I see tons of people using the lee's. What is really wrong with them?.

The answer: Nothing is wrong with them!

I have had very good luck with the Lee pro 4-20 bottom pour pot. I liked it so much that I bought another and run 2 of them side by side. It's possible to get a drip now and then from any bottom pour pot. The main complaint with lee pots dripping is with the 10 pounders. Also make sure your pot stays clean so nothing clogs the spout. Again.. this is something you have to do with every bottom pour pot.

Shad

[Echo]

The purple is lead oxide - the gold is tin oxide. Think about it - as thin as it is, precious little oxide is actually formed, and mainly when the temp is too high. Fluxing pulls the oxygen out, putting the metal back where it belongs. No drama...
And when I cast, I put an ingot on top of the furnace to warm up, As I cast, and the level goes down, I drop the pre-warmed ingot in the melt and replace with a fresh one on the rim. Keeping the pot fairly full maintains head-pressure, and keeps the addition of fresh alloy from dropping the melt temperature too much.

[Marlin Junky]

The purple is lead oxide - the gold is tin oxide.

That's ridiculous... what color is the sky on your world?

When Pb oxidizes, it turns gray.

Stannous oxide has two forms, a stable blue-black form and a metastable red form.

The color casts we see on top of our casting furnaces are exclusively related to temperature.

MJ