Fluxing with sawdust.

[hawkeye1]

Just tried fluxing with sawdust. Smells good but seems like it takes long time for the sawdust to burn to char. And it doesn't stir into the mix. Is this what it's supposed to do? Do I scoop off the charred remains before I scoop for making ingots?

[mdi]

Sawdust provides carbon for cleaning, it does not reduce into the alloy. Unless you want ashes/charcoal in your ingots skim it off (if you are cleaning in your bottom pour pot the ash floats to the top so it doesn't really matter)....

[hawkeye1]

That makes sense. Thank you. I kept thinking I must have missed a step.

[nhyrum]

It doesn't stir into the mix, but you'll want to try you want as much of the charcoal to contact as much of the lead as possible.

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[dannyd]

Try a wooden paint stick; works good

[GregLaROCHE]

Make sure the sawdust is 100% dry when adding to flux.

[fredj338]

Either your alloy isnt hot enough or you are using too much sawdust. I only use sawdust when making ingots. I will flux twice, the sawdust chars in seconds when stirred in. Scoop off the crud & pour ingots. When I cast, I use a wooden paint stick to stir the pot every time I add alloy.

[oley55]

Just tried fluxing with sawdust. Smells good but seems like it takes long time for the sawdust to burn to char. And it doesn't stir into the mix. Is this what it's supposed to do? Do I scoop off the charred remains before I scoop for making ingots?

the last sticky in this section titled "fluxing technique" is an interesting read if you are into self-torture and ok with being way, way far off in the weeds.

I for one remain mostly confused about the whole fluxing thing and continually wonder if what I'm doing is right or wrong, good or bad. I've read we should try to get the charred wood down into the mix but I wonder if that is only trapping char in the mix. Then I've read long and vigorous stirring is required along with scrapping of the sides and bottom of the pot. I do try to stir n scrape until there isn't any remaining hint of black dust floating back to the surface, but it seems some will pop back up while ladling. A sure sign I am missing something...or does the introduction of a cold ladle cause the release of the suspended carbon?

I do use fine powdered saw dust and I think it helps collect and trap the trash. After the saw dust has been skimmed off I'll drop in a pea sized chunk of bee's wax, wait for it to char and then stir it in and then skim.

As for wooden paint stirs, mine having been split into threes and set on end in a cup on my work bench for months still contain enough moisture to cause minute spatters and you can feel the moisture boiling out through the stick. I'll chock that up to living on a Florida saltwater marsh and not an option for me.

[Mk42gunner]

One very big thing to keep in mind is that at least 99% of us on this board are casting enthusiasts, and we tend to take things to extremes. Example: If a little fluxing is good a lot of involved fluxing is better, right? Not necessarily so.

If your alloy is clean enough to cast good boolits, it is clean enough. Doing more is just adding work. If you are cleaning a big haul of wheelweights, the ingots will oxidize as they wait to be cast into boolits and still require a bit of fluxing in the casting pot.

When I smelt (lots of arguments over that word) the wild wheel weight into ingots, I tend to flux or reduce once with an oil or waxy substance, then once with sawdust. I stir with a stick from the yard (I have lots of trees).

When the alloy is a clean silvery color, I start filling ingot molds. Don't believe that everything floats to the top immediately, I have had a steel ww clip suddenly pop to the surface when I had a bout ten pounds of alloy left in my 100 pound pot.

When I fill my electric casting pot, I flux again with a bit of left over boolit lube stirring with a stick. Skim the dross and start casting.

I do save the dross and include it in the next smelting session. It is heavy, it has to have at least some lead in it.

Basically, figure out what works for you. Don't be afraid to try new techniques though.

Robert

[Jack Stanley]

Something I learned when i was melting Magnesium at the die cast shop is to keep the flux on the top of the melt . The way we fluxed at the shop was to bring the metal at the bottom of the pot to the top leaving the flux on the top . And the way that was done was with a propeller on a shaft driven by an electric motor .

What I do here at home is use a metal paint stir that is meant to be used on a drill . You don't have to run it fast , just bring the bottom metal to the top so it can be in contact with the flux . It work no matter if I'm melting twenty pounds in the small pot or five hundred in the larger pot .

Jack

[Huskerguy]

I melt a lot of range scrap, think o have 6 buckets waiting on me right now. At our range you will find most anything in the scrap including paper from targets, wads from shotgun shells, back stop belting and who knows what else. I Flux my range mix twice just because, the first with sawdust and the second with beeswax or candles. I often wonder if I am just wasting time as I firmly believe all the junk I collect in the range scrap ends up acting like a Flux. I can get some very nice looking range scrap with zero fluxing.

[littlejack]

I bought a potatoe masher at Good Will years back. It is the one that has little stamped out diamonds. The ones with the handles spot welded on, will eventually separate so I replaced it with one that was riveted to the handles. I put the sawdust on top and then do the old up and down butter churn method.Then I use a long handled tea spoon (with holes) to stir the sides and bottom. Gets my alloy mix very clean. Haven't had any inclusions. I ladle cast in the 20 pound pot.

[oley55]

I do save the dross and include it in the next smelting session. It is heavy, it has to have at least some lead in it.

I had the same thoughts from a recent COWW rendering session and was convinced I was skimming off my tin and/or antimony. So I started putting my skimmings into different tin cans. One for obvious trash n stuff, the other for what appeared to be be mostly metal of some description. When I put that blob of metal dross in with a relatively clean smelting pot full of alloy and fluxed with beeswax, 95% of it immediately recombined with the alloy and produced some nice clean looking ingots.

Now when fluxing and skimming my casting pot, I pretty much do the same, using two different skimming containers and recycle the metal dross. Again, the beeswax seems to make that surface grey matter almost instantly recombine, leaving a mostly clean and clear lead surface. At least that what it seems like......I sure wish there was a way to validate this whole lead alloy fluxing thing.

[Bigslug]

I've done the "stir the ashes" thing, but truthfully, I'm a little dubious about it actually accomplishing much over just stirring and scraping the pot.

Lead is REALLY heavy. Most of the junk in the pot is comparatively REALLY light and will float to the top. If you're smelting with a bottom-pour pot, your clean stuff is at the bottom. Anything that doesn't get cleansed out in the initial ingot pour will float to the top of the casting pot (again, away from your spout) when it's re-melted to make bullets.

If you're ladling for the entire process, it'll be more critical, but again, the crud is light and will float like a duck on a pond. Skim off what you can or push it aside, but even so, that which ends up in your ladle will float to the top of that and be the last thing out of the spigot.

Seems like a lot of sleep lost for no reason to me. YMMV.

[GregLaROCHE]

Make sure you are stirring the beeswax into the lead and not just letting it burn off.

[nhyrum]

I've done the "stir the ashes" thing, but truthfully, I'm a little dubious about it actually accomplishing much over just stirring and scraping the pot.

Lead is REALLY heavy. Most of the junk in the pot is comparatively REALLY light and will float to the top. If you're smelting with a bottom-pour pot, your clean stuff is at the bottom. Anything that doesn't get cleansed out in the initial ingot pour will float to the top of the casting pot (again, away from your spout) when it's re-melted to make bullets.

If you're ladling for the entire process, it'll be more critical, but again, the crud is light and will float like a duck on a pond. Skim off what you can or push it aside, but even so, that which ends up in your ladle will float to the top of that and be the last thing out of the spigot.

Seems like a lot of sleep lost for no reason to me. YMMV.What the flux is doing is removing impurities on a molecular level from the lead. Things that get dissolved into it. Just like salt in sea water doesn't just "settle out".

There's a great book that goes pretty in depth in fluxing, it's called from ingot to target by Glen Fryxell. It covers far more than that and is definitely worth reading

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[gwpercle]

I like to use pencil sharpener shavings , place a tablespoon on the melt and drizzle 1/4 teaspoon melted beeswax over the shavings and stir vigorously with a little wooden paddle untill it's reduced to fine charcoal .
The combo wax / wood shavings works best ... And two small fluxes works better than one big one .
Gary

[dondiego]

I like to use pencil sharpener shavings , place a tablespoon on the melt and drizzle 1/2 teaspoon melted beeswax over the shavings and stir vigorously with a little wooden paddle untill it's reduced to fine charcoal .
The combo wax / wood shavings works best ... And two small fluxes works better than one big one .
Gary

Smells so good!

[everybodydiesintime]

I only use sawdust for Flux. I have a big spoon with holes in it that after I sprinkle some on top I use the spoon to push it down in to the lead.i does wanna float but after staring it down a few times it's burnt and trying to float I scrape off the ash/carbon repete as needed but not so much that your removing all the tin/antimony. And start making ingots.

[lightman]

I use Pine saw dust or chips in my smelting pot. I put about a coffee cup full on top and let it char well and I usually light it. It takes a while to char. Then I will aggressively stir it while scraping the sides and bottom of the pot. I usually do this twice. I don't put sawdust in my casting pot though. Only wax or bullet lube.

[TCLouis]

I was using sawdust until I tried the fines out of the bottom of a bag of charcoal.
Seems to fully protect the surface and probably reduces the oxides as they form, I never see them or have to wax treat the melt to get them back in the mixture.

Unlike most, I cut and drop the sprues right back into the pot.

IF I were shooting for hundredths of inch precision, I may set the sprues aside and compare boolits produced both ways on a scale and down range on paper.

[Bigslug]

What the flux is doing is removing impurities on a molecular level from the lead. Things that get dissolved into it. Just like salt in sea water doesn't just "settle out".

There's a great book that goes pretty in depth in fluxing, it's called from ingot to target by Glen Fryxell. It covers far more than that and is definitely worth reading

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Yes, but Fryxell or no Fryxell, for the most part we are already working with pretty well cleaned and refined alloys (wheel weights, range scrap, bars from Rotometals, etc...) that might have some grease, dirt, or oxides on them which will typically float like a cork along with everything else that's closer to the top of the periodic table than lead.

Yes, there's often a microns thick level of tin oxides that can form on the top of your casting pot, but it can be stirred back in. . . and the multiple pounds of stuff below it is fine.

I'm not going to say that it HURTS anything, but IME the whole sawdust cleanse thing seems to run more on superstition about a mythical boogeyman in our alloy than providing actual benefit.

[littlejack]

IME, the superstitious sawdust does what I expect it to do. If I scrape and stir voraciously, my pot of alloy, theres not a whole lot that happens. But, when I drop in a couple teaspoons of sawdust, stir it, submerge it, scrape the walls of the pot, theres lots of debris that sticks to it and floats to the top to be skimmed off. I'm not a scientist, not even close. But if someone tells me it doesn't work for me, doesnt know what they're talking about.

[charlie b]

Sawdust works for me as well. Smells better than beeswax :)

[Bigslug]

IME, the superstitious sawdust does what I expect it to do. If I scrape and stir voraciously, my pot of alloy, theres not a whole lot that happens. But, when I drop in a couple teaspoons of sawdust, stir it, submerge it, scrape the walls of the pot, theres lots of debris that sticks to it and floats to the top to be skimmed off. I'm not a scientist, not even close. But if someone tells me it doesn't work for me, doesnt know what they're talking about.

Hey, whatever floats your wood waste. Seems to me that the only "purifying" it accomplishes is from the extra scraping, stirring, and spooning you have to do to remove the ash of the sawdust you've added - any extra "fish" you catch is only because you've made more casts into the lake. Lead, being dense and heavy, does seem to force crud to the sides of the pot, and mechanical scraping is the ticket there - - but, my take is this: if it's loose in the pot, it floats; if it's not, it's stuck to the sides. In neither case is it going out the bottom-pour spout of either the smelting pot into the ingot mold or the bottom-pour spout of casting pot into the bullet mold. By the time you're making bullets, you've float-cleaned your metal twice. Technically, maybe even three times - as any unlikely crud that makes it through the double gauntlet will probably float to the top of your sprue plate.

Guess I'm just highly agnostic to the Religion of Sawdust. Do I need to be concerned about what you guys do to heretics? :target_smiley:

[littlejack]

No worries.
Years ago I used to use a bottom pour pot. Believe it or not, there are heavier metals (or whatever) that sink to the bottom of the pot. Using sawdust, stirring and scraping, with my ladle casting procedure leaves my cast projectiles with no inclusions or foreign particles. But, when I was using the bottom pour procedure, there would sometimes be inclusions in my projectiles from the heavy particles lying on the bottom of the pot and dropping out when the lead was filling the mould. Just sayin.

[fredj338]

Yes, but Fryxell or no Fryxell, for the most part we are already working with pretty well cleaned and refined alloys (wheel weights, range scrap, bars from Rotometals, etc...) that might have some grease, dirt, or oxides on them which will typically float like a cork along with everything else that's closer to the top of the periodic table than lead.

Yes, there's often a microns thick level of tin oxides that can form on the top of your casting pot, but it can be stirred back in. . . and the multiple pounds of stuff below it is fine.

I'm not going to say that it HURTS anything, but IME the whole sawdust cleanse thing seems to run more on superstition about a mythical boogeyman in our alloy than providing actual benefit.

When I am melting scrap, range or ww or whatever, it is hardly refined alloy. I think it is quite helpful to flux alloy well before making ingots. Only clean ingots go into my casting pot & that gets fluxed with a wooden paint stick. I have tried casting without fluxing & get better fill-out fluxing so it isnt just a feel good thing.

[Old Caster]

I can guarantee there are still particles after lead is fluxed no matter what you do or a bottom pour spout would never clog up. When I pressure pour cast with certain molds I like for the pour to be rather slow and slow enough so that a solid pour won't go to the plate below but will be solid for a couple of inches and then drip looking. The reason I do this is because if I have it go in too fast I will see dirt occasionally in the base of the bullet. I think when it goes in slow it is not suddenly crammed in and can float to the top and get back into the sprue before it gets hard. I only do this for bullets that are used for competition because I want the best and most of the time I am using an 069 Saeco 200 grain mold which has very small holes in the sprue plate. It is a genuine pain to cast this way because the level of lead has to be very close so I add a pound every 35 or so bullets out of my Waage pot that has molten lead to add so as not to change temperature or pressure. Lately I have more problems with spout clogging than in the last 50 years and I assume that zinc or something is in virtually any lead that is picked up at the range which is what I normally use. I do have some pure that I might add tin to in order to see if it improves the problem but I am getting old enough that my 45 scores are no longer that good anyway and I am no longer very competitive and sometimes just pour at a faster rate without pressure pouring.

[dale2242]

I had some issues with inclusions until I started fluxing with shaving that are used for bedding and a small piece of candle wax.
I flux this way when my melt gets up to temp and whenever I add sprues and/or new alloy to the pot.

[WRideout]

I have had good luck cleaning up wheel weights etc. with vegetable oil that had turned, and was not edible. It seemed to clean the lead off the clips better than almost anything, and it smells like french fries. I just melted down a pot of range scrap today, and dosed it with a little motor oil. It seemed to be fine. When casting with my little Lee dipper pot, I will throw in a partially used birthday candle for one pot, and seldom have to do it again. Nothing against sawdust, but I am more likely to have a wooden stick around to stir with.

Wayne

[JohnH]

When I'm smelting (reducing COWW or other lead/alloy) to bullet metal, the best flux I've ever used is burnt motor oil. It's all about carbon. Fluxing is chemistry in action. Oxygen is a free radical and will bind with anything that has an open spot. She's a good 'ol huzzy. WThe trick to fluxing is to add or create an environment that has something the oxygen would rather combine with and carbon is the element. Anything that is carbon rich will do the job and the richer the better. Dry leaves will work so far as that goes, as will tallow candle wax, bees wax and other high carbon materials but the winner winner chicken dinner is burnt motor oil.

I smelt in a cast iron dutch oven between 10" and 12" diameter at the top. Once I've scooped off all the clips and other non lead debris I take 1 to 1 1/2 table spoons of oil and pour it on top and begin to stir. I May or may not add that much again as I'm stirring, and I'll light off the smoke. Smells like crap and it's prolly a method to be avoided in an urban environment. You can also soak your sawdust or wood chip (I use red cedar chip bedding from the pet dept in Walmart) in oil.

But do understand that it's all about the chemistry. The oxygen would rather bind with the carbon than the lead/tin/antimony and it is this molecular shift which creates the reducing we see in the dross. I agree with another poster, we prolly do too much fluxing. I keep a layer of kitty litter atop my casting pots, I bottom pour, so I rake back a spot and slip and ingot in (I keep my pot topped up as a cast) then recover and go on about casting. Ladle pourers are the one's who need to keep a constant flux going on the melt as every time they dip into the melt they are exposing the melt to oxygen.

For a while now I've wanted to make a smelting pot with a bottom pour valve so I can pour directly into my ingots and reduce the amount of cleaning/fluxing I do in that operation. 'Nuther one of those roundtuit projects.

[Mandoair]

I’m not a boolit caster. But gona be one someday. I read a book I got here “from ingot to target “. Very informative. He recommended saw dust to lay on top of lead to reduce the tin back into the mix. Stops oxidation from occurring. When I was experimenting with melting lead into ingots I m sure now that I was skimming off all my tin. Education is expensive. I am also wondering what is coww. Wheel weight some thing ❓

[oley55]

coww-clip on wheel weights
soww-stick on wheel weights

somewhere on this board there is a "board used acronyms" stickie, but danged if I can find it right now.

edit: I was mistaken, it was/is a stickie for boolit coating acronyms: https://castboolits.gunloads.com/showthread.php?257663-Commonly-used-Acronyms-in-Boolit-Coatings&highlight=acronyms

[Joe S]

I just came upon this thread and dont know if this has been mentioned or not but wood chips from a router or planer work better ( for me anyway) than sawdust.
Regular sawdust is too find and much harder to remove. Your mileage may vary, of course.
Joe S

[charlie b]

My sawdust tin is a mix of saw dust (from saws :) ) and shavings from hand planes. By the time I remove it from the pot everything is ash anyway.