Melting lead dust to cast?

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Jenrick

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So I have access to a pretty much lifetime supply of pure lead dust at work. I can collect it and bring it home in a safe way due to us having the appropriate PPE at work. The question is how do I go about smelting it down without causing an issue? I could obviously could just mask up and deal with the airborne lead issue, but I'd prefer to not have to wear a tyvek suit and respirator all afternoon.

If it wasn't melting metal, I might suggest wetting down the dust into a kind of slurry and then melt it down. However as it is lead, and we all know what lead and water do, is there another option? They use oil in casting sand specifically to avoid the steam issue. Also possible, what about suspending the whole mess in wax? Due to the wife making candles professionally I've got more then enough wax.

So anyone have any suggestions?

-Jenrick
 
I do not see why you could not just wet down the dust and put it in the pot. BUT start every pot full at room temp and slowly warm it to remove the water/steam. Note* I have not tried this with lead dust BUT HAVE done this with lead rings from old sewer piprs and scrap that have been soaked with water with safe results.
 
Jenrick wrote:
lifetime supply of pure lead dust at work
Click to expand...

Okay, we'll quickly move past the fact that I am quite envious of your supply of powdered lead.

Essentially what you're dealing with is the field known as "powder metallurgy".

This site gives a good overview of the considerations:
http://www.pm-review.com/introduction-to-powder-metallurgy/the-powder-metallurgy-process/

From here you can do an internet search on the topics that might be relevant to you. You mentioned the possibility of using wax to avoid the "tinsel fairy" (a term I only learned yesterday) which would presumably float on top of the lead and that opens the door to the entire field of "liquid phase sintering".
 
I had access to some 90 pound ingots and the only way I could get them into my 40 pound casting pot was to cut them in thirds. I spread a plastic tarp and used a Skilsaw with carbide blade to cut them up. The carbide blade was used because the teeth are wider than the saw blade, which cuts a kerf wide enough that the blade won't bind. What this left me was a whole pile of lead shavings, since I had a lot of the ingots to cut up.

I gathered up all the shavings from the tarp and just put them in the pot with the rest of the alloy and it melted right down. I don't see why you couldn't do the same thing with your lead dust, as long as you're mindful of the problem of moisture in the dust. As you're probably aware, moisture isn't always obvious when dealing with lead and lead alloys.

When I'm smelting large amounts of lead into ingots, and moisture is present, I use sawdust for flux. When charging the pot with new alloy that may contain moisture, I place a layer of sawdust on the molten alloy in the pot about an inch thick. Then I pour the new alloy on top of the sawdust, which allows the moisture to cook out of the newly introduced alloy. I've been doing it this way for years and haven't had a problem with it. The only drawback is there will be copious amounts of smoke, so do this outside.

Hope this helps.

Fred
 
Have you smelted lead before? I'm not really sure what the concern would be. Put the lead into the pot and add heat. Unless your in the middle of a tornado the lead dust isn't going to be blowing around and if you happen to be in the middle of a tornado you've got larger problems than lead dust. You can use a lid if it's windy. I use a lid but only because it traps the heat and warms up quicker.

When adding lead just pour it into the pot. I'm guessing anything considered lead dust will melt immediately once hitting the pot. Wear gloves and appropriate safety gear. You don't have to stand over the pot as everything is coming up to temp. Wash you hands when you're done. Its not radioactive or anything like that.
 
I"m with RedDog81. After you're rolling there will be a pool of molten lead, and the next scoop-full of dust will melt almost immediately until you add enough to cool the pot.

In this situation, be careful to add the dust slowly (a ladle-full at a time) in case there's a bit of moisture in the dust. You wouldn't want a clump of dust, with moisture, to become submerged. The moisture will boil off safely so long as there's only dust between it and the surface.
 
hdwhit said:
Okay, we'll quickly move past the fact that I am quite envious of your supply of powdered lead.

Essentially what you're dealing with is the field known as "powder metallurgy".
".
Click to expand...

Since the OP just wants to smelt lead powder this message has really lots of potential for improvement...simplest done by erasing/ overreading/ forgetting it.
Powder metallurgy is something different and it does NOT include smelting.

Carsten
 
The dust I'm dealing with is about the consistency of powdered sugar. A decent bit WILL get airborne even just from scooping it. To deal with the dust issue, normally we wet everything down before it's moved at work. That would be the simplest option here, basically creating a wet slurry that I can just pour into the pot. I was thinking about adding said slurry to an existing melt, which was where the problem of introducing water to molten lead occurred. However as several folks mentioned, if I just brought a whole batch up to temp at once, the water would evaporate off long before molten lead existed. I do like the suggestion of using a layer of sawdust to insulate the two mediums, and that's something I'll play with potentially. The big draw back being a lack of sawdust as I don't do much woodwork.

-Jenrick
 
If you have a cabinet shop nearby, they have lots and lots of sawdust they're more than happy to get rid of. Just take a couple five gallon buckets and I'm sure they'll fill them for you. Some of it will be pretty fine from their dust collectors, but it still turns to carbon when burned, and that's your fluxing agent.

Absent that option, a chainsaw and a log will also produce a lot of usable sawdust/shavings that work just fine, too.....

Hope this helps.

Fred
 
PLEASE PLEASE be extra careful if you're messing with Lead and especially with LEAD DUST.

You can easily get it on your clothes and spread it all over your house poisoning yourself, your family and pets.

Just a tiny bit can contaminate 1/3 the area of a football field.

My suggestion is to take a lead safety class if you haven't if you have, PLEASE follow safe practices when handling it, cleaning up, and such.
 
I appreciate the warning, we receive training at work. That's why I've been looking at options to avoid introducing an exposure hazard with airborne dust. I think wetting it down, before I do anything with it is the best option, as it's what we would do at work to avoid the dust hazard. I just wanted to verify that was a safe way to melt it down, and based on the responses here I'm comfortable with trying it.

-Jenrick
 
As long as you don't add wet metal to already melted metal, should be no problem- The water will have evaporated long before the metal can melt. Just empty your smelting pot after each batch, let cool before loading each subsequent batch.

Suggest starting each batch with a layer of sawdust over the Lead, as the large surface area of dust vs. ingots will tend to oxidize more than big chunks do. Best to have the flux between dust and air from the beginning.

What is the Lead dust used for (or scrap from) at your job?
 
I'm a full time LE firearms instructor, our backstop features a deceleration trap with negative pressure ventilation to keep the airborne lead exposure down. Basically when the rounds hits the backstop, it shatters into pretty dang small fragments and gets sucked into the collection trap. Probably about 5% make it into the actual trap as a whole projectile, where they decelerate and drop into the collection trap. We generate about a 55gal drum of lead scrap, with the majority being dust or very small fragments (sand grain size), every two weeks, I don't recall exactly what that weighed last time but I want to say it was close to 3,000 lbs. As we shoot exclusively jacket rounds (the only bare lead is from shotgun's) all the bullet cores are close to pure lead (close enough for casting minie balls at least), based on previous testing, and confirmed by an assay report from our recycling vendor.

-Jenrick
 
To speed up your process get a second pot to melt the lead in and set it over the heating pot while it is at a lower temperature it will start to evaporate the water as they both heat up. Just be darned sure that it cannot spill into the hotter pot of lead. Use a couple spacer bars over the first pot to hold the second securely and allow the first one to breathe. Let us know how you make out.
 
Jenrick said:
That would be the simplest option here, basically creating a wet slurry that I can just pour into the pot. I was thinking about adding said slurry to an existing melt, which was where the problem of introducing water to molten lead occurred. However as several folks mentioned, if I just brought a whole batch up to temp at once, the water would evaporate off long before molten lead existed.
Click to expand...

The water will cook off at ~212F leaving the lead dust sitting there as before up to ~620F. So the water is only present for 1/3 of the process. For the other 2/3 of the process you still have lead dust. I don't see a big advantage for using the water.

Add just enough lead that the molten product will cover the bottom of whatever pot you're using. Once the bottom of the pot is covered in liquid, you can add more powder. Any powder added will be captured when it hits the molten puddle AND liquefy rapidly. You can do this with or without the wood chips.

Just my 2 cents.
 
Wow, "Chicken Little" lives! If the lead is in the consistency (powdered sugar) you mention, you're not going to get a huge dust cloud whenever it's poured into the pot. Use common sense and don't dump the powdered lead from 4' and sit next to the pot while pouring the dust doing deep breathing exercises. What will your total exposure time when pouring the dust? 30 seconds? You can hold your breath that long. Work in a well ventilated area. Just think. You work with this substance (I'm assuming for several hours per day) and should have all the info available for sensible handling for very short handling. Every time lead is mentioned on a reloading forum the fear warnings/scare tactics about "lead poisoning" abound. Use common sense. But, if you wanna "suit up" with full PPE, go ahead...

There are more old wives tales and fear concerning lead for casting bullets than almost any other factor of our shooting/casting/reloading hobby.
 
ca9ee4f0-81b7-4083-98ba-6bfb50b51b4e_zps98ffcaf5.jpg

200bb607-2421-4b88-8ca2-fb68a783d02d_zps0932a0ac.jpg


The "dust" had about the same consistency of granulated sugar (maybe a little coarser) but was mostly soaked in WD-40 so there was no fine dust to worry about. The gathered lead dust was about 2 pounds so it's very worthwhile to save and melt.
 
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