Idea for a flux

[Cowboy_Dan]

So when I'm "smelting", I typically use wood shavings sold as rodent bedding. I put the lid on the pot so that less carbon is lost to smoke as it chars. The other day, I was at a yard sale and saw a 3/4# jar of activated charcoal (marked as somthing to do with fish tank filters) with a $.50 sticker on it and thought to myself that charcoal is what that bedding turns into, so this will speed things up while propane is burning. So I bought it figuring that I'm only out four bits if I'm wrong.

Am I right that this will work to flux my scrap? And should I powderize it before using it?

[Outpost75]

I do bulk melting outdoors and just use a Chok Full-O-Nuts coffee scoop of used motor oil and flare off the smoke to kill off any bugs.

[JSnover]

Try it. The worst thing that could happen is it floats to surface and you skim it off.

[warf73]

Make sure it is very dry, activated charcoal is very porous and holds water very well. I would put it in the oven for 15mins at 350 to be safe but that's me.

[gundownunder]

Sawdust. Your local timber and hardware store will give you bags of the stuff for free from their cutoff saw. This is all I've used for years

[runfiverun]

all your looking for is the carbon to get into the melt and carbourize the alloy.
that's fluxing.
lighting stuff on fire on top of the melt returns the oxides back to the alloy.
that's reducing.

set your charcoal on top and let it dry break it up against the sides then work it throughout the alloy.
don't use very much. [a pinch is plenty]
the trick to carbon is getting it back out again.

[1989toddm]

all your looking for is the carbon to get into the melt and carbourize the alloy.
that's fluxing.
lighting stuff on fire on top of the melt returns the oxides back to the alloy.
that's reducing.

set your charcoal on top and let it dry break it up against the sides then work it throughout the alloy.
don't use very much. [a pinch is plenty]
the trick to carbon is getting it back out again.

Thanks for the simple explanation! Fluxing has (and still does) confused me for a long time. Is it so necessary to reduce the oxidation back into the alloy?


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[mdi]

I've used charcoal briquettes, BBQ fuel. Seemed to work OK, I smashed some chunks into small bits any dumped about 1/2 cup on top of about 20 lbs. of scrap lead and stirred. Seemed to work...

[bangerjim]

Pine sawdust from my shop saws 3X to flux + a little paraffin wax the last time to reduce.

Works for me every time. Why break the chain?

Beeswax only in the casting pot to reduce the Sn back in.

banger

[runfiverun]

the oxides your returning back to the alloy are generally Tin rich, it oxidizes out first,
then the lead itself.

adding in the carbon helps the alloy bind together properly to form the SbSn chain with the lead.

carbon has a bad habit of staying in the alloy and taking a while to ride the heat currents to the top.
it will also find anything along the pot walls or the bottom of the pot to cling to.
this is why when you scrape the bottom and sides of your pot you get that little bit of extra black powder stuff coming to the top.
it's also why when your done smelting ww's down and you turn the empty pot over on the ground you get all that gunk out.

[jmort]

100% pine shavings for pet bedding works well. Price is negligible.

[fredj338]

I just use sawdust or wood shavings. Free from any wood project I do or HomeDepot. Just make sure you don't get MDF or plywood. The glues can be nasty.

[gray wolf]

Sawdust. Your local timber and hardware store will give you bags of the stuff for free from their cutoff saw. This is all I've used for years

So far the wheel has worked for a long time, don't reinvent it.

[trapper9260]

I use ground up corn cobs and dose ok with it.Since I also use it for my brass also in the tumbler.We grow our own pop corn so when there is just the cobs left I had a farmer ground up a batch for me.It did not cost me anything also.

[Nick Quick]

So I should NOT light up the saw dust? Is that correct?

[Bent Ramrod]

I always thought it was the resins in the wood that did the fluxing. I only light the smoke when it's heavy and obnoxious, like wax smoke. Sawdust smoke isn't as intense and has a pleasant odor so I don't bother.

I've read that a layer of charcoal on top of already clean lead will keep further oxidation down, and works good with a bottom pour pot, but I've never heard of using it as a flux.

[runfiverun]

you want the sawdust to char and burn to charcoal.
light it on fire if you want.

most here use sawdust and wax.
they light the wax on fire, this burns the wood into carbon.
and it also gives us the oxygen free barrier on top needed to reduce the oxides back into the alloy.

this oxygen free barrier is how Marvelux/Borax works.

[Nick Quick]

Thanx a bunch runfiverun. Much obliged.

[Shiloh]

I tried the sawdust remedy. Cedar shavings as well. I like what I see and will stick with it.

SHiloh

[bangerjim]

Some people have respiratory problems with certain oily woods when burned. Cedar is one of those. Walnut is another. (Walnut bedding will actually sicken/kill some animals!) Just be presonally aware if you use those woods! Especially if you are bothered by any breathing problems. I only use pine and alder sawdust because I cut a lot of it in my shops. Alder also makes great meat smoking wood!

Pine sawdust is pretty much our standard on here. Get some CLEAN sawdust, not the free stuff from big box stores as they cut many composite and glued-up materials that contain nasties you do not want to breath either. Pine bedding from Walmart is dirt cheap for those that are power saw-challenged. Just buy some.

banger