wood chips and sawdust flux

[farmbif]

not to take a poll or anything but wondering what size wood chips or saw dust is the most ideal for fluxing.,
I usually just grab a couple handfuls from under the radial arm saw. but I have huge piles of red cedar chips that the planer throws out.
I find that for some reason pine or cedar sawdust work real well when melting down a pot of really dirty wheel weights.
I've tried catching sawdust from the chainsaw when cutting up firewood and it works ok too. but the cedar stuff has a great aroma.
ive had a thought of making blocks of bees wax and cedar sawdust for fluxing.

[Valley-Shooter]

I use what ever is handy.
Sometimes I empty the bag on my chop saw. I have been known to chop up scrap wood on that saw just to make saw dust. Douglas fir is usually what I have on hand.
When I'm in a hurry I grab hardwood pellets from my pellet grill, but those pellets are compressed and take longer to burn.

I think pine and fir sawdust is the best.

Sent from my Pixel 4 XL using Tapatalk

[StuBach]

I just use whatever sawdust is in my dust collector at that time which is mostly pine but sometimes has a mix of hardwoods in it.

Your beeswax and sawdust block idea intrigues me, would be nice to make some (maybe in an ice cube tray) and just drop one in as needed. Currently I drop in sawdust and a couple of beeswax pellets so this could potentially speed my process up a little.

[BNE]

I’ve made sawdust/wax blocks. They work well.

BNE

[Hossfly]

I use pine bedding chips like for horse stalls. They’re kinda big and slow to catch fire so will light them to hold down smoke. Usually do this with the large pot when melting down wheel weights.

[Buck Shot]

I just grab a handful from under the table saw. Usually mostly yellow pine but also some oak. I think the resin in the pine helps.

[lightman]

I've used everything from the fine saw dust from the table saw to the chips from using a chainsaw to the flakes from a planer. They all work fine but I think Pine does the best job. Maybe its the rosin in it?

[uscra112]

Rosin by itself makes a primo flux. Personally I don't use sawdust anymore because I can't be sure that it's completely dry. I haven't had a "tinsel fairy" event but once or twice I saw significant steam coming off it before I started ti stir it in.

[heebs]

I am of the planer chips/dust collector crowd. Fine dust is good but chips last a little longer. I really like it when melting down range scrap or anything dirty. Seems to collect the dirt better, then follow up with either beeswax or candle wax. I make shot, so clean lead is imperative.

[imashooter2]

No table saw and jacking on a hand saw to make sawdust isn’t high on my how to spend a day list… I use pine shavings pet bedding. A buck and small change years ago for a bag that will last years more.

[MrWolf]

No table saw and jacking on a hand saw to make sawdust isn’t high on my how to spend a day list… I use pine shavings pet bedding. A buck and small change years ago for a bag that will last years more.

Same here with a bag of pine bedding. I would cut all types of wood including pressure treated so a lot safer just using the pine shavings.

[trapper9260]

I use ground up corn cobs . Had a farmer ground up the cobs in his feed mill for me and the amount he done for me will last me for a long time. I save my bees wax for making my bullet lube and what other use I need it for.

[pworley1]

I use a mix of heart pine planer chips and saw dust from band mill.

[dale2242]

I use pine planer shaving used for pet bedding.
I add a small piece of candle wax to the flux when I am casting or smelting.
Adding the shaving has reduced my inclusions to near nothing.

[sqlbullet]

Digging into the archives:



gearnasher 02-19-2013, 08:45 PM (https://castboolits.gunloads.com/archive/index.php/t-184987.html)

Murphy, there is a lot of misinformation given already here as to what exactly does what, so I'm going to try to clear it up for you with scientific facts confirmed with the experience of a whole bunch of us.

OK, here's the deal, as figured out a long time ago by a Ph, D. chemist named Glen Fryxell. There's three things we do with our dirty scrap alloy to process it: There's cleaning dirt out, there's reverting the oxide scum back into useable, elemental metal (called "reducing", the opposite chemical reaction to the process of "oxidizing", which is what makes the scum in the first place), and there's FLUXING, which is removing the dissolved metals we boolit casters consider impurities because they impede the flux, or "flow" of the metal when we try to cast things like boolits out of it.

To get the dirt out, it usually just requires a good scraping, stirring, and skimming because it will float to the top. Unless the dirt is denser than lead, like Uranium, but I haven't seen much of that in my boolit metal.

Then there's getting that tin-rich oxide scum to go back in rather than skimming it and tossing it. This is where the "reduction" of oxides takes place, and that requires only heat and unburned hydrocarbons. You can use wax, grease, oil, tallow, butter, margarine, tree bark, grass, sap, hair, ground coffee, cereal grains, rosin, vaseline, etc. You get the idea. The hydrocarbons react with oxidized metal to make carbon dioxide, water (vapor), and DE-oxidized boolit metal. There will be a tiny bit of ash unless you can make the reaction in your open pot stoichiometric, which you can't, and it doesn't matter. Just skim the pinch of grey powder and call it good.

Now, there's FLUXING. This is the part that is mostly misunderstood. A chunk of candle was DOES NOT constitute flux. Marvakrap does, but it has a lot of drawbacks, and it doesn't REDUCE OXIDES at all, neither does kitty litter. Kitty litter doesn't even flux, but I digress. Back to fluxing. Most lead scrap has all sorts of evil junk in it like calcium, iron, aluminum, zinc, cadmium, you name it. We want that stuff GONE but want to keep antimony, arsenic, copper, and tin, along with any trace gold, silver, or copper that might be in there. The thing that does it all is CARBOHYDRATES, and sawdust has plenty. Yes, you can flux with potato chips, if you don't mind the salt corroding things. But you said you hate the stuff I call Marvakrap, so that rules out salty snacks for flux.

Since Rosin and sap makes an excellent sacrificial reducant, and carbohydrates do too, sappy pine shavings make some of the very best flux/cleaner/reducant to be had anywhere at any price.

But in order to get the fullest effect you must expose as much of the metal to the smoldering sawdust as you can so it can soak up that nasty calcium, aluminum etc. etc. while also sitting on the top and keeping oxides reduced. Oxides float, and putting the sawdust on top takes care of reducing them back into the alloy, but to really get the bad junk out you have to expose all the metal in the pot to it. To do this when smelting, first I toss in some wax to reduce the oxides out of the clumpy, dirty junk floating on top after getting all the scrap melted and skim all that off. Then I put about an inch of chainsaw debitage on top (the bar oil residue helps some too) and let it start charring really good. Then I take my big ladle and scrape the heck out of the bottom and sides of the pot and get it stirred up good, then start bringing up big ladlefulls of alloy and drizzling it through the smoldering sawdust layer. I do this over and over again until the sawdust is just a grey ash, which I skim off and toss, then add another layer and repeat. If there is a lot of the junky metals in there, you will notice a big difference in the ash from the first fluxing to the second or third fluxing. The ash from the first fluxing will be more like burnt aluminum foil and later fluxing ash more like fine powder.

That's it! After cleaning, fluxing, and ingotizing, you may not need to flux any more. When casting, if you got the bad junk out during the smelt, all you need to do is keep the oxides reduced, if even that. Kitty litter is good for sealing the surface of the casting melt from oxygen on a bottom-pour setup or to insulate and keep heat in during cold-weather casting, but in and of itself does nothing to absorb impurities or reduce oxides. During casting, you can use wax to keep the oxide scum reduced, stir with a wooden stick, or do what I do and float about a quarter inch of sawdust on top of my casting pot, because as it burns to ash it seals the surface just like kitty litter does, only is easier to clean out and less dusty. The charring sawdust layer, while actively charring and before it turns to ash, is also a great reducant for the flash-oxide that forms on sprues, so if you toss them back in the pot as you cast it will help keep the excess scum caused by that process from forming. You might skim and refresh the sawdust periodically if you wish while casting. Otherwise, grease/wax/oil will keep the oxides at bay.

Hope that sheds a little light,

Gear

So, for these reasons I use dust, and the dustier, the better.

[higgins]

Oiled sawdust has been recommended occasionally. When I tried it, I got mine by removing the sprocket cover on my self-oiling chain saw and got ready-made oiled sawdust. I have since settled on candle wax (paraffin?) since I got a bag of broken candles several years ago.

[StuBach]

Upon reading the others posts I think I’ll stick to what I’m doing which is saw dust with bees wax chips I get from Amazon. $20 bag of chips lasts a long time when a little is coupled with pine saw dust from my TS/Drill/router.

[oley55]

I have read and been of the impression we flux for two distinct reasons. One we flux to remove impurities and the other is to recombine alloys. So I flux with sawdust to clean my alloy and then use a tiny blob of bees wax to get my tin and antimony recombined with the lead if/when I see them floating on top or when adding some tin/pewter to my alloy.

I wonder if using both at the same time is really doing what we are hoping for. It seems like the combination would be cancelling out one or the other. Or am I cornfused again?

[imashooter2]

Wax and sawdust do the exact same thing. Add carbon to reduce oxides back into the melt. The cleaning is accomplished by stirring and scraping to allow trash to rise to the surface to be skimmed off.

[JoeJames]

I generally have a low mound of pine sawdust where I have push broomed it from my table saw. Works just fine. But a buddy got the idea after reading Ingot to Target, used some sawdust, and set off the smoke alarm on his alarm system at his main house.

[lightman]

I have melted some wheelweights that would have set an alarm off. I got one bucket this year that had a master cylinder turned up sid down in them and another bucket that had an oil filter draining in them. They were fun to sort! :-(

[JoeJames]

I have melted some wheelweights that would have set an alarm off. I got one bucket this year that had a master cylinder turned up sid down in them and another bucket that had an oil filter draining in them. They were fun to sort! :-(I too have found some strange stuff in my buckets. I now have more valve caps then I will ever need. But it is sure worth the trouble, ain't it? We are lucky to be in the Arkansas for many reasons.

[Budzilla 19]

We have a sawmill, so pine, rich pine even better, sawdust for me! Last time we cut wood, after Hurricane Laura last year, I got 55 gallon drum of pine and cedar together, so it’s sawdust first, then paraffin for me. Works good, your mileage may vary,

[DME72]

i use whatever sawdust i have on hand in the shop. oak,pine, maybe a little cherry or other wood. works great.

[kevin c]

Pine planer shavings and sawdust for me, a couple rounds including paraffin wax when processing. Scraping down the pot I do, but not geargnasher's mixing and pouring technique. I got more inclusions (black spots in ingots and casts) that way, maybe carbon carried down into the melt by stirring according to my reading.

Admittedly this was when I started out, and I may not have been careful cleaning the pot prior to pouring. Since then I haven't seen many issues from not doing the pouring through technique, but it could be because my new lead source is very clean (radioisotope containers). I also melt my lead at least three separate times before it ever gets to the casting pot, using wax and sawdust each time, so maybe the cumulative effect is the same as what gear was recommending.

[dondiego]

I always add a book match in with the sawdust. It almost immediately ignites and reduces the smoke volume considerably.

[kevin c]

I do that too. But, I was thinking ("A dangerous pastime"; "I know"): I've read that it's the carbon monoxide from incomplete burning that works best for oxide reduction, so is it actually better to let things smolder?

Any chemist out there want to comment (don't be gentle, I'm a crotchety old guy who can take it)?

[dondiego]

It seems to work for me. I am a chemist but don't know much about fluxing and reducing in a lead pot other than my experience doing it.

[kevin c]

I should think that experience trumps theory.

[Lloyd Smale]

i think a big mistake many casters make is over fluxing. I flux till i get no crud or very little when i smelt down lead and very rarely flux in my pot. It may be nessisary for a ladle caster but i never saw where it did anything positive for a bottom poor caster.

[JonB_in_Glencoe]

not to take a poll or anything but wondering what size wood chips or saw dust is the most ideal for fluxing.,
I usually just grab a couple handfuls from under the radial arm saw. but I have huge piles of red cedar chips that the planer throws out.
I find that for some reason pine or cedar sawdust work real well when melting down a pot of really dirty wheel weights.
I've tried catching sawdust from the chainsaw when cutting up firewood and it works ok too. but the cedar stuff has a great aroma.
ive had a thought of making blocks of bees wax and cedar sawdust for fluxing.

Dust, not chips.

One time during a long smelting session, I ran out of sawdust, so I ran to the lumberyard. They let me take whatever was in the dust bin by the panel saw. What I got, was sawdust with some plastic shavings (Lexan?) and likely plenty of glue from OSB and plywood. I tried to grab the dust with as little plastic shavings, as possible Using that did stink, but I was smelting outside with a lite breeze, and I always lite the smoke on fire...so toxic smoke smell wasn't a big issue. It worked just fine, but I prefer pure wood sawdust. Once that session was done, I trashed the rest of that plastic/glue filled sawdust, and haven't used anything but pure wood sawdust ever since.

[Buck Shot]

i think a big mistake many casters make is over fluxing. I flux till i get no crud or very little when i smelt down lead and very rarely flux in my pot. It may be nessisary for a ladle caster but i never saw where it did anything positive for a bottom poor caster.

I'm new to casting, but I've wondered about that, too.

Judging from the YouTube videos I've watched, there is no obvious indicator of "how much fluxing is enough" and it looked to me like you could continue fluxing and drossing until the end of time, or until the pot was empty, whichever came first...it just seems like the more flux you add, the more dross you get, and every time you skim off the dross, all you do is expose fresh molten metal to oxygen, creating more dross to remove, exposing more fresh metal to oxygen -- it seems like it never ends. Does it?

Lately, I've been leaving the sawdust/carbon on top of the melt to act as an oxygen consumer and shield the molten metal from oxygen somewhat...IIRC, cellulosic welding electrodes like 6010 and 6011 use cellulose/sawdust to create CO and CO2 to gobble up any oxygen and shield the puddle...

[JoeJames]

I'm new to casting, but I've wondered about that, too.

Judging from the YouTube videos I've watched, there is no obvious indicator of "how much fluxing is enough" and it looked to me like you could continue fluxing and drossing until the end of time, or until the pot was empty, whichever came first...

The free online book: From Ingot to Target is the best I have found on fluxing, well, and casting in general. Read it. It, and the advice from others on here really got me started producing good boolits.

[bangerjim]

What ever species of wood dust is under the table saw from the last project. If it is carbon-based, it will work as a flux. In the fall I use dried leaves in the back yard around my casting station!

[reedap1]

I use pine dust/small chips from a planer. I will plane down a fresh green pine board and then screen the chips to collect fine pine dust. I find that the bigger chips are good for fluxing the initial melt and alloy processing where the fine dust is good when actually casting bullets. A small blob of candle wax follows the fluxing and I can cast for a full pot with good results.

[lign]

I use hardwood from my planer and jointer. Mostly oak and cherry. Smells better than the stinky pine we have around here and makes people think I'm running the smoker :-) I rub the chips between my hands a bit to make them smaller and less fluffy. Finer stuff is good too when I have been using tablesaw or bandsaw enough. I let them smoke a while before stirring in to prevent any moisture surprises...
sqlbullet gave the best reasons from Fryxell about why to use sawdust instead of other fluxes.

[fredj338]

IT doesnt really matter. I use what ever sawdust I have around, no MDF or plywood dust, for fluxing as I render scrap to alloy. Once casting, I just use a wooden paint stick to stir the pot every time I add clean alloy.

[oley55]

i think a big mistake many casters make is over fluxing. I flux till i get no crud or very little when i smelt down lead and very rarely flux in my pot. It may be nessisary for a ladle caster but i never saw where it did anything positive for a bottom poor caster.

Still mostly a new guy here smelting wheel weights, but something weird happens when I ladle into my ingot molds. I can flux twice or more with saw dust. I work the charred dust down through the lead and stir and stir for at least three minutes. I then carefully scrape every inch of the inside of my cast iron pot and then stir and stir some more before spooning off all remaining dross and carbon. But as soon as I put my steel ladle into the lead, some (not a lot) black carbon seems to come out of the lead and float to the top. It's almost as if the black carbon is suspended in the lead and gets released as soon as the slightly cooler ladle enters the lead. Kinda frustrating because I wanted my ingots as clean as reasonably possible so I won't have to flux so much on my casting pot.

Does this sound normal, or am I doing something wrong. FYI I use one of those 4" round flat skimmer spoons with a bunch of holes in it. Seems to help get the charred carbon down into the alloy and mix everything together without splashing lead.

[GregLaROCHE]

I am of the opinion that almost any dry plant based material works. It’s the carbon in it that does the work. Perhaps sawdust or chips from a wood with a high resin content is a plus. I use whatever I have on hand. It’s usually sawdust, but I have used dry leaves and small bark chips. Once when everything outside was wet, I used Quaker Oats from the kitchen.
Also, when I an melting scrap to make ingots, I only use sawdust etc. I save the beeswax for the casting pot after I have fluxed with sawdust or something similar.

[dondiego]

Still mostly a new guy here smelting wheel weights, but something weird happens when I ladle into my ingot molds. I can flux twice or more with saw dust. I work the charred dust down through the lead and stir and stir for at least three minutes. I then carefully scrape every inch of the inside of my cast iron pot and then stir and stir some more before spooning off all remaining dross and carbon. But as soon as I put my steel ladle into the lead, some (not a lot) black carbon seems to come out of the lead and float to the top. It's almost as if the black carbon is suspended in the lead and gets released as soon as the slightly cooler ladle enters the lead. Kinda frustrating because I wanted my ingots as clean as reasonably possible so I won't have to flux so much on my casting pot.

Does this sound normal, or am I doing something wrong. FYI I use one of those 4" round flat skimmer spoons with a bunch of holes in it. Seems to help get the charred carbon down into the alloy and mix everything together without splashing lead.

Could the black stuff be coming off of your ladle? Seems like that might be it.

[oley55]

Could the black stuff be coming off of your ladle? Seems like that might be it.

I don't think so. Aside from some very light surface rust powder it was/is clean. I thoroughly cleaned prior to and during my next batch of COWW and still seemed to get a little black soot popping up. The amount of black popping up is small but irritating in that, "where did that stuff come from?" I'm probably being just too anal again.

[dondiego]

I don't think so. Aside from some very light surface rust powder it was/is clean. I thoroughly cleaned prior to and during my next batch of COWW and still seemed to get a little black soot popping up. The amount of black popping up is small but irritating in that, "where did that stuff come from?" I'm probably being just too anal again.

Does the carbon come up when you use a different stirring device? Maybe try a paint stirrer.

[gwpercle]

I'm a little late to this party ...hurricanes and such ... but an ideal source of wood shavings is old fashioned wood Pencil Sharpeners ... pencils are made of Cedar wood , the sharpener shavings are a nice size and thickness , just right for flux and nice smelling . The little bit of graphite doesn't hurt .
I empty the sharpeners at my office and at home and if you know a teacher she/he can score you all the Sharpener Shavings you need ... a lot has changed but a lot of writing still goes on with a number 2 wooden pencil .
Gary