Make Ingots or Shot after the pour?

Hi All,

Next odd question.

I'm buying a tiny melting unit, a 70lb brass capacity tilting furnace, pick it up next week and getting ready to play while the weather cools. No desire to do this during the summer, plus I'm busier in the summer, so no free time.

If you ever buy casting wax in bulk in comes in little pestules? little mis-shaped drops. I keep them in a big tote and scoop them as necessary, really a nice way to store them.

I have quite a bit of scrap metal I need to deal with, copper, brass, bronze, they are all separated, no chip, just chunks bits and the like. A few hundred pounds.

I'm looking to melt it down into a convenient form. I personally like the idea of making it into shot, don't you just pour it into water? And little drops form? Watched a few videos on Youtube and that appears to be the way they do it. A few places even sell it that way. Some of the drops are a little messed up, but this is for quickly emptying the crucible at the end of the day and storing the remaining metal for use later.

Questions?

Could it trap water inside the pellet? That would be a problem on the remelt.

Does it affect the remelt in an adverse way, more surface area so a little more oxidized metal, besides that?

Those are the two big ones.

If you have experience with this, advice would be greatly appreciated.

Thanks
Aaron

I've been thinking about this video for other reasons, this was a good excuse to actually go and find it.
Building the Burner and Lead Shot Dripper - YouTube
I think shot would be simple out of lead, I wouldn't want to try it at a temperature high enough to melt brass or bronze though. The blacksmith I trained under had ingot molds made out of 1 1/2" angle iron, Just a row of single lengths with ends welded on, at a 45 degree angle. The long skinny triangle ingots were really easy to stack and cut to weight.

I always wondered if ingots could be too big and carelessly dropped into the pot break it. I suppose they could be jammed from side to side and crack the pot as they expand from the heat so best to keep them vertical. Of course that is why a crucible is tapered on the inside. so there is no lip to stop a ingot from growing in length.
Bil lD

Hi All,

I've seen his video, he does good work. I thought about the angle iron thing too, still kicking around options. I like the idea of scooping material, easier to keep that way. Bars are great, pellets are better, just working on getting there.

Commercial ingots of bronze are 70#'ish. Drop them in a pot they will break it. Drop them on your foot, break that too.

Have to play with it a little more.

Thanks
Aaron

If you try pouring in to water you'll end up with globs. Pour gently into a wood trough (just a v) that drains in to water...if that makes sense. The wood trough gives it time to ball up and pour a thin stream, the molten metal is kept in a reducing environment because of the wood, and most of all, it keeps you away from the inevitable steam and allows you to pour with more control.

On a commercial scale, shot is made by pouring it in to an intermediate graphite crucible with a hole in the bottom. The graphite crucible is heated with an induction coil.

btw, you CAN pour directly in to water if you are good enough....but it's best that the water is kept moving, either with a garden hose just pouring in and keeping everything moving or a pump or even a propeller on a drill, otherwise you end up with steam tunnels.

If your crucible is 70lbs brass capacity, then that's about an A20-A25 crucible size, there would be no advantage in melting your scrap twice to pour a casting. After all, you would have to get the scrap pieces into the crucible to melt it in the first place. There is time, energy, fluxes used and fuel burnt to melt the material, not to mention burning off some of the zinc in brass so the most efficient thing to do is melt the crap and cast it into the usable object immediately and by usable object this includes ingots to be sold to other users. You would start by getting whatever scrap fits into the crucible without jamming it in so tight, the crucible is cracked by the expanding metal. If your furnace has a flat top, you can use the exhaust gasses to preheat heat the next items that are too large for the pot up to a dull red heat and then using tongs and a larger hammer, break them up to fit the crucible.

If you put wet shot back into a hot pot it will explode...bad idea to have any water around your pour...Phil

My very amateur experience pouring aluminum into water is you end up with a spongy mass that probably has trapped water pockets. I think lead shot towers are 100 feet tall or more.
Bil lD

Hi All,

Snowman, yes that does make sense, I was thinking about using angle iron V but you're saying a wood V, Poplar is cheap and easy to use, it's my go to utility wood in the shop. I can make a V from that, back to the reducing environment, that would be because the wood it trying to burn and locally consuming the oxygen? I was thinking about misting a little water down the V, either iron or wood, just a little mist. Give it something to cool a skin. I like the wood idea. Yes, of course keep the water moving, lots of pumps to stir this.

SAG, I agree it's a waste of energy, and it might degrade my brass a little, brass is my least used metal so it it loses a little shine that's fine with me. It's more of a first time playing with this furnace, which is ELECTRIC!!!! I know, fancy and all. But I want to play with it a little, new to this animal and I need to see how it plays before I do it for real. It also gives me time to clean up a little scrap, clean shop, play with new toy, make some little metal beads. What's not to love. After I'm done with the first scrap load, I'll just stay caught up with it and use the scrap mixed with new, standard practice. I just have a lot this first time out.

Phil, No we do not put wet anything in the furnace, bad stuff happens. But would it trap water is the question. With Snowman's V trough I think it will skin before it hits the water, which would solve the problem.

Yes, Bill, a true shot tower has the metal fall a ways, that's so the ball forms uniform and some other things. I think copper is a little hotter and a lot more dense than aluminum so it doesn't form the sponge. Guys on Youtube (land of many idiots) They are making beads/shot occasionally, but often they are making some type spadder thing. Then the polish it? Why does anyone polish and ingot? or make shot spadder into some type of ornament? So they are close, I just need to fill in a few gaps to get to the result I'm looking for.

So lightly misted V channel made from Popular dumping into a rapidly swirling tank of water. I even have some surfactant sodium lauryl sulfate, lower the surface tension a little. A gram goes a long way, so I don't think it will change the chemistry much.

Thanks
Aaron

I am using a piece of 1 1/2" channel iron 3/4" deep to make small ingots in. It is about 10" long and I welded end caps on at a slight angle, similar to the sides of the channel. The small crucible I use holds just enough to fill it so it works good for me. They stack nice if I can keep the pours all the same volume. Nowhere near 70 lbs, not even lead, maybe 6 or 8 lbs of zinc.
Next step with bronze and aluminum is to get bigger molds for ingots. Thinking of 3" channel 12" long.

Thanks Snowman,

You provided the missing piece. The graphite crucible with the holes. Googling that got me a manufacturer of the crucible, they sell them on ebay. but they give the hole size 3mm and the other dimensions. Not hard to make. It's called a graining crucible or drilled crucible. Once you figured out that, look for the videos on youtube.

Yes some dumb ones, but a few that are production quality, some are company product videos. It's common practice to do it for precious metals and other jewelry grade metals, easier to weight out to make the proper alloys.

So now I just need to make a graining crucible, some type of stand to hold it above a bucket, few little parts here and there and good to go.

Rob, that's why I'm working on making the balance of the pour into shot, easier to work with, convenient to store and I don't need bunches of molds. Just a different way to skin the cat.

Thanks
Aaron

Aaron-M said:

Rob, that's why I'm working on making the balance of the pour into shot, easier to work with, convenient to store and I don't need bunches of molds. Just a different way to skin the cat.

Click to expand...

I know I would spill or drop or contaminate the shot somehow. I dont do much with these and they sit and get moved around. It sounds like shot in different metals is the way to go to accurately mix your own alloys

Good idea to decide how you will tell this shot or ingots apart in storage. Ingot scan be stamped brass, bronze, zinc etc. Shot no way to mark except the bucket. If it spills into a different bucket or two buckets fall and intermix? I do not know if that is really a problem for you or not But I have lots of mystery metal that may be tool steel or not. I forgot and never marked it. And I have no marking color code system anyway.
Bil lD
Bill D

There are significant issues melting granular metals (swarf) in hopes of casting it into ingots. The high ratio of surface area to mass guarantees much or most will be lost to oxidation. I believe commercial melters of scrap use very high pressure compactors to press swarf into semi-solid form prior to melting and melt in a controlled atmosphere. You do see a number of guys on YouTube melting cans into “ingots.” What you won’t see is them then melting those useless ingots and casting them into useful castings—-wrong alloy, poor yield.

This forum is not the optimal place to get foundry information. You will get more hands-on experience-based responses at Thehomefoundry.org.

Denis

I am in and out of lots of Foundries and have never seen any of them pouring leftover melted metal into water. Yes their crucibles or furnaces are much larger but the principles are the same.

Every time you melt brasses bronzes and aluminum you are likely degrading the alloy. All the non ferrous Foundries I work with buy ingot and the only scrap they're melting is internal scrap. Even that they limit the mount of remelted metal that goes into a heat. Oxygen is your enemy in melting why would you increase your oxidation by a huge amount.

I have seen metal ingot moulds with a wash on them in non ferrous Foundries but usually just open topped sand moulds.

The other thing is to melt as rarely as possible so you are not dumping molten metal. A lot of smaller or even medium sized foundries not running automatic moulding machines only pour in the afternoon. 2-3 man foundries it might be only a couple of times per week. Get as many moulds ready as possible. That way your are saving energy and not melting the same material over and over again.