Fluxing lead for casting?

[jimmy82]

Got some questions about fluxing the lead for casting RB's. For starters what exactly does it mean? I only know about fluxing from a soldering point of view. I've heard you can use beeswax, and since I have some already it might prove useful.

Do you rub it on while the wax is solid? Or do you melt the wax and rub on?

Do you flux the molten lead (add a chunk, let it melt and stir)? If you do how much do you add to the melt?

I understand the basic theory behind casting but I need some finer points for this fluxing stuff.

 

[boar]

I get my lead molten in the ladle, then put small chunk of beeswax on top of lead and let it burn off. Dilly

 

[paulvallandigham]

Fluxing lead involves putting a small piece of beeswax into the molten lead, where it floats. Then stur the lead to bring the dross up to the surface. With new lead-- ie., lead that comes from lots of sources, with oxides already on it, you can first skim off the surface of the molten lead to remove whatever is there. Then flux. Do this in open air, or a very well ventilated room. The beeswax burns and smokes a lot! You may have to flux more than once. It all depends on how dirty the " new " lead is.

I make a practice of pour newly melted lead into ingot molds, cool them, and then use the ingots for melting lead for bullets and balls. That allows some separation of the impurities through cooling and sedimentation. So that its easier to clean the lead by fluxing when I get around to pouring bullets or balls. As you pour, more impurities will work their way to the top, and oxides will form on the top in any case. If you use a bottom pour mold, this does not affect the quality of your castings. If you are dipping lead from the pot from the top, it does, and you therefore have to skim the top off more frequently.

I got a bottom pour furnace, after years of using an open top one. I believe I got fewer bits of crud in my castings using the bottom pour pot, and therefore fewer rejects. Having said that, I learned through long trial and error to pour consistent bullets and round balls using a dipper.

Oh, when fluxing, use a circular motion with your spoon on a slant, so that you are pulling impurities to the surface to combine with the beeswax residues. When the impurities mix, they tend to stay on the top and float on the surface of the lead so you can remove them. You can't push the beewax down into the molten lead, because of the difference in density, so don't even try.

 

[mazo kid]

Yep, put a piece of beeswax or candle about the size of a pea on the molten lead and stir it in from the bottom. I've heard that using saw dust works well too and you can leave the carbonized residue on top to prevent further oxidation (assuming you have a bottom pour pot) Emery

 

[FPDoc]

I use a candle to flux with and just dip it onto the surface of the melt until I get the "right sized" puddle, then stir with a spoon in vise-grip jaws. It will smoke and you can light the smoke to burn it off so it isn't such a mess. Marvelux is a commercial product available to use if you prefer (I can't tell the difference). I pour from the bottom of my pot.. but without touching the spout to the mold and I provide a generous "button" for shrinkage. I have very, very few voids (don't remember the last one actually). I used to weight them to cull under-weights/voids (if I started to have problms I would again) but only visually inspect usually (if it looks perfect it likely is). If there is the slightest question it gets remelted because it's easier to cast another perfect one than to break your rythm. I do weigh for cast bullet target loads and I do segregate suppository rifle bullets by cavity used as well. It's about consistency and basic skills/understanding of the process. A very important thing is... DON'T allow a single drop of moisture (sweat/spit/drool/condensation/beer etc..) to hit the melted lead, that ONE drop of water = big lead explosion/steam-splash. That is considered "bad form". Lots of good advise in previous posts.

 

[BrownBear]

While I flux regularly when casting alloy bullets for CF guns, I never flux lead for muzzleloaders. The point of the fluxing in the CF world is to help tin and to a lesser degree antimony back into the alloy. But you don't want that stuff in your ML lead. Not fluxing is my way of letting the impurities come out of the lead as they want. Differnt stroaks for differnt fokes.

 

[FPDoc]

That is true regarding the extra alloy elements in #2 alloy or Wheel Weights etc. and is a primary reason to flux in those cases. In my lead supply there is also a lot of junk/dirt/dust/etc. that floats to the surface and can be skimmed. With clean pure lead to start with you are probably correct (I wonder how much you could de-alloy something like Wheel Weights with multiple melts and bottom taps?). Mine is usually pretty dirty/oxidized/weathered etc. during the first ...ingot/making... session and that is what I was thinking about. Excellent points Brown Bear.

 

[boondocker]

I flux with old candles ,the grandkids broken crayons, dry sawdust( important) and for the frugal in mind we never leave the diners with out the courtesy crayons the kids use. Im with brown bear on the flux the tin on my cf bullets but it seems to clean up the crap a little in th ml melt. Cant hurt. Boon :thumbsup:

 

[Blizzard of '93]

like Paul V. says stir your melt well and scrape the bottom some, impurities that the weight of the lead holds to the bottom will float to top. skim this off then stir in the wax flux small stuff comes up. light the fumes but sure keep your head out of the fumes and be outside. :v

 

[gmww]

In addition to scraping the bottom, I'll scrape the sides which seems to bring up some impurities that I skim off the top.

 

[MSW]

paul got most of the points. i use beeswax (a pipe major gave me a bunch of the stuff, but you can use the parrafin from a candle stub, too) and since i'm using the smaller of the Lee bottom pour melting pots, a bit a little bigger than a pea seems to do the trick. stir the sides and top, and skim off the funk with a spoon.

the note about any drop of moisture is well taken- even a drop of sweat will make things a bit more exciting than you need or want.

do this out doors, be upwind of the process (if there's a wind blowing) and (don't do like me) wear closed toe shoes and gloves. i don't think you need to wear a respirator, but you certianly don't want to eat or drink anything while casting. wash your hands when you're done, too.

 

[squirejohn]

I used to use beeswax or parafin to get rid of impurities in the lead pot. Now I just stir and scrape the pot and haven't noticed any difference except for the lack of smoke and stink.

 

[jimmy82]

Cool, thanks for all the info :hatsoff: My father-in-law said he's got a pot and dipper that I can have. It would be fun to play with and experiment. I already plan on making my own lube, why not balls too. :v

 

[Dphar]

Got some questions about fluxing the lead for casting RB's. For starters what exactly does it mean? I only know about fluxing from a soldering point of view. I've heard you can use beeswax, and since I have some already it might prove useful.

Do you rub it on while the wax is solid? Or do you melt the wax and rub on?

Do you flux the molten lead (add a chunk, let it melt and stir)? If you do how much do you add to the melt?

I understand the basic theory behind casting but I need some finer points for this fluxing stuff.

The best way is to use Marvelux then before it sets add a little beeswax it speeds the process. I'm out of Marvelux right now so I use Beeswax.
Marvelux does not smoke but takes a little while to harden if you allow it to stay on the metal that long.

Dan