wood chips and sawdust flux

[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.