Flux in or out??

[shredder]

When I flux my melt and skim off the resulting trash, It leaves me wondering if I am doing it right. I am using a lee bottom pour furnace.

I make sure the melt is up to temperature (30-45 minutes), put on my big leather welder's gloves then stir the pot top to bottom with a metal spoon. I then put a small amount of parrafin (like a pea) in the spoon and it immediatly melts. I then use the spoon to stir the melt again and of course the parrafin ignites and burns for a short while. I continue to stir slowly and dross rises to the surface. I usually leave it for a short while then slowly and carefully skim it off.

My problem is that I think I may be depleting my melt of antimony and possibly tin. What I am skimming off looks at first like sand but after cooling it is a dull grey coarse grained metallic looking stuff. Lumpy and fairly heavy. A good 2 or 3 heaping tablespoons from 10 lbs of 50/50 alloy. Is it possible to flux OUT the antimony from the alloy? Is that a normal amount of trash from what appeared to be clean ingots of alloy?

[SlippShodd]

Well, to my not so expert mind that sounds like a bit much for dross from a 10# melt. I used to just skim it all off assuming that it was all oxidized metal and of no further use. Since being edumicated by the more experienced members of this forum, I've gotten a little more picky and flux a couple times with the parafin, then stir in a pile of sawdust, ignite it with a lighter if it doesn't self-ignite. That usually reduces the pile of dross considerably and I skim whatever is left after the flames die.
I have however started keeping the dross in a tin can and when a considerable amount has accumulated, remelt it in my smelting pot and reclaim whatever molten metal is produced. When casting out of the bottom pour pot, I just cover the melt with sawdust and never let the dross get to the pour spout. When I'm done casting, I skim the melt and either let it cool in the pot, or pour it off into ingots.
Your mileage may vary.

mike

[MikeS]

I have a 20lb pot, and I normally will put a handfull of wood shavings (Pat Marlin's CFF mixed with hamster bedding) in the pot, and stir it in pretty good, then leave it on top of the pot during the casting session. When I need to add ingots, I use the ingot to push aside the shavings before dropping it into the pot, and I never let the pot get less than 1/3 full. At the end of the casting session I will remove what's left of the flux from the top of the melt using a ladle with holes in it so it doesn't take too much lead with it, and then turn off the pot, then refill it with ingots. This way the cold ingots help solidify the melt, as I don't like to leave a pot with molten lead unattended, and by adding the ingots after the pot is turned off helps the whole thing solidify quicker.

I used to just leave the ashes in the pot all the time, and just added to them with fresh flux for each casting session, but I've found that by removing them after each casting session my lead seems to be a slight bit cleaner than it was before, and before it was worlds cleaner than when I used a wax based flux! Now the only time I use a wax based flux is when I'm remelting boolits that have already been sized & lubed, but even so I always add enough wood based flux to soak up the wax, otherwise the wax makes my pot dirty. Wood is the way to go for fluxing lead and lead alloys.

To answer the OP's question, while it might be possible to remove some tin & antimony by fluxing too much with a wax based flux, I don't think you'll be removing enough to worry about. Now if you use something like Marvelux or other borate based flux, you'll suck most of the tin out of the alloy! I don't know about the antimony, if borate will remove it too, or not.

[williamwaco]

My problem is that I think I may be depleting my melt of antimony and possibly tin. What I am skimming off looks at first like sand but after cooling it is a dull grey coarse grained metallic looking stuff. Lumpy and fairly heavy. A good 2 or 3 heaping tablespoons from 10 lbs of 50/50 alloy. Is it possible to flux OUT the antimony from the alloy? Is that a normal amount of trash from what appeared to be clean ingots of alloy?

1) What is 50/50 alloy?
2) Could your 'stuff' be described as looking like metalic oatmeal?

The metalic oatmeal is often described as being caused by zinc contamination but one member here had some analyzed and was told it contained no zinc.

I don't know what causes it but I do know that when it happens to me, it always happens after allowing the pot to "cook" for 30 to 45 minutes.

My lee pot, starting from room temprature is ready to cast in no more than 25 minutes. 45 minutes is WAY to long to wait.

If you are going to flux with paraffin, start as soon as as the alloy will stir like water. one 'pea' is not enough. use at least two and three if there is dross on the top. Stir vigorously, scraping the sides and bottom of the pot with your spoon. Use the spoon to circulate alloy from the bottom of the pot to the top.

If the smoke doesn't ignite, you can ignite it. Depending on conditions, the smoke will ignite at around 700 degrees. When it does self ignite you are at about perfect casting temp. ( Actually a little above. I get best resultst at around 650.)

The good news is that you are not removing antimony. I have skimmed a pot like that until 80 percent of it was skimmed off and bullets cast from the remaining alloy weighed the same as those cast before the skimming had the same BNH readings. You cannot BNH test the skimmings because they are full of air and are very soft.

If you have enough, you can remelt all those skimmings and clean them up somewhat by fluxing repeatedly with sawdust. ( at least five times. )

DO NOT ADD THOSE SKIMMINGS TO GOOD ALLOY. YOU CAN ADD A POUND OF 'OATMEAL' TO A 20 POUND POT OF GOOD ALLOY AND YOU WILL CREATE 20 POUNDS OF 'OATMEAL'.

No amount of fluxing with wax or oil will have any effect on this condition.

Be sure you cull out any zinc wheel weights before melting them. They can cause this problem but are probably not the only cause.

Do not 'cook' you alloy. If you are not going to be casting for 20-30 minutes. Turn it off.


I agree with others here that sawdust does a better job than paraffin. But I still use paraffin at least half the time.




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[Frank]

The easy way to see if your flux is working is compare it to Marvelux. I found wax didn't do the trick, but Marvelux was good.

[kenyerian]

I also save the dross in a coffee can and smelt it one more time when I get enough. Hate to waste anything. I do keep it separate and don't mix it with anything else. I generally flux it twice .

[leftiye]

First, get a good flux. Which is a hardwood (or not) stick - to stir with. I don't remove anything from my melt. In other words you're removing too much. After the first flux (with saw dust), you've got all of the crud off. Stop skimming at that point. Paraffin does work, but not too well in my experience. The best stuff I've found is the Buck Beaver flux on evil bay, but it is not needed unless you're getting inclusions in your boolits out of your bottom pour pot. I crush charcoal and cover my melt with it while casting (and don't flux = stir until I refill my pot). Sprues and new ingots are melted in a separate pot/heater, fluxed and poured into main pot. Incidentally, this makes a 10 lb pot adequate to fairly high production. Lots and lots of threads about flux and fluxing here BTW ( use the search option, hint hint).

[runfiverun]

those are the oxides you are skimming off.
so no you are not fluxing properly.

[shredder]

Thanks for the responses fellows.

My 50/50 alloy is equal parts pure lead and smelted wheelweight metal. All in Lyman ingots. Got it from a local gunsmith who has been in business many many years. I will try the wood for fluxing and try to be on the spot quicker when the pot reaches temperature. Still learning. While I have cast many many good bullets I also beleive I can learn a few new things around here.

[MikeS]

shredder: While you might be able to cast good bullets now, you might find if you do a bunch of reading here, starting with the stickies you might find that soon you're casting GREAT boolits! There's lots of great info to be found on this site, you might even find after a while that you'll look back at some of the boolits you've cast, and wonder how you considered them good. It's also entirely possible that after reading the info you'll find you've been doing things the proper way, and that what you're calling good might really be great after all! After a while you might even want to start spelling them with the forum approved word.

[shredder]

shredder: After a while you might even want to start spelling them with the forum approved word.

Ha Ha Ha! All right I give! Fro now on I shall refer to all said 'lead castings' as "BOOLITS" even though my spelling senses tell me not to do it!

So much great info on this site and so much experience. No sense trying to re invent the wheel. I will give sawdust a try today and stir with a paint stick. I will then cast some boolits and see how things go. ( see, I can adapt):castmine:

[Longwood]

I wanted to make some milling balls for making black powder in small quantities using a Harbor freight rock tumbler.
I have a length of brass that I can machine some balls from but that would be very time consuming so I thought I might try casting balls instead.

Which metal do you guys think would be best?
Soft lead or much harder Linotype?

Now for my related question.
If I use Linotype, and do not flux, but rather let the melt oxidize. Will the oxidation be lead or another metal?
In other words, do you think the melt metal will cast harder or softer balls if I let it oxidize some?

Should I start machining the brass?

[leftiye]

Yes. Ball bearings would be more convenient, but you don't want anything around black powder that can spark (guess why). Linotype balls could werk.

Tin oxidizes most readily followed by antimony, then lead. I.E. there will be a disproportionate tin and antimony content in your dross. After the first fluxing and skimming, you want to reduce the oxides back into your melt

[williamwaco]

shredder: While you might be able to cast good bullets now, you might find if you do a bunch of reading here, starting with the stickies you might find that soon you're casting GREAT boolits! There's lots of great info to be found on this site, you might even find after a while that you'll look back at some of the boolits you've cast, and wonder how you considered them good. It's also entirely possible that after reading the info you'll find you've been doing things the proper way, and that what you're calling good might really be great after all! After a while you might even want to start spelling them with the forum approved word.

I have been casting since about 1956 and I can cast very good bullets.

I can also cast junk.

Since I found this forum and have been reading the postings. I can cast much better bullets, more consistently, with fewer rejects.

Hang around. You will get better quickly.


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