Saw dust

[lead chucker]

when you flux i have been using sawdust and beeswax do you skim it off after its burnt up or leave it on there so the lead doesnt oxidize. Some times i think my tin and antimony are getting cleaned off the top.

[ku4hx]

Circa 1970 when I started casting, I bought, read and followed Lyman's instructions in their cast boolit manual. They instructed the caster to clean the dross off, so that's what I did.

It's worked beautifully for me over the years so I see no need to alter my casting methodology.

[Charlie Two Tracks]

I leave the sawdust on top. It seals it up and keeps the heat in also. I use sawdust only.

[buyobuyo]

It's probably a waste, but I generally flux twice. Flux the first time to make sure everything is reduced and cleaned up. Then I scoop it out and flux again and leave it on while I'm casting to help keep oxidation down. I also only flux with sawdust.

[bearcove]

From what I have found by reading and doing it seem best to leave the sawdust on the melt.

When smelting I skim it off because I use a ladel then, but casting boolits I usually bottom pour so it stays on and is refreshed on occasion.

[cajun shooter]

I purchase my wood shavings from Pat Marlin. It is not a dust as a normal blade cut leaves behind but more of a shaving of mixed cedar type woods. I use one hand type pinch for the flux and remove it and the dross it forms.I then sprinkle a good layer over the top to have both a nice smell and keep the alloy from oxidation

[waksupi]

Circa 1970 when I started casting, I bought, read and followed Lyman's instructions in their cast boolit manual. They instructed the caster to clean the dross off, so that's what I did.

It's worked beautifully for me over the years so I see no need to alter my casting methodology.

Keep in mind that Lyman has recommended this site for casting info. This board has changed a lot of things since 1970, and we now know that skimming that off, is removing tin from the alloy.

[leftiye]

Crushed charcoal. I put a spoonful (heap tsp) on and flux. Stir with a stick, and stir deep, scraping the sides of pot. I leave it on, it turns to ashes, I leave it on adding more charcoal before fluxing (stirring) each time I replenish the pot. If too much accumulates I remove some. I leave a layer about 1/4" thick on top of my lead. Plus I have a sheet metal cover over my pot too.

I have tried everything from paraffin to leaves, to sawdust, including stearic acid (very good flux), this charcoal works best and there's no fluxing every five minutes either. BTW, I DON"T skim. EVER.

For the wierd oxides that get down in a bottom pour pot and become inclisions and surface impurities on my boolits- there's a Buck Beaver caster's flux on eVil bAy that werks wunderz.

[geargnasher]

I do what buyobuyo does, based on the education I got from reading Glen Fryxell's articles on the chemistry of fluxing, and several discussions with a good friend of mine who's an industrial chemist.

Add sawdust, stir it in good with a dry stick, let it char, stir with a spoon, skim the ash, add more sawdust, let it sit until the pot's empty. This "reduces" (chemically) the oxides from the melted boolits/ingots/muffins that went into the pot to fill it initially, absorbs any trace aluminum, iron, etc. that's still in the lead after smelting, then all that gets pulled out of the melt. Fresh sawdust keeps the oxygen away and keeps the tin and antimony from "flash oxidizing" on the surface and depleting the alloy.

Gear

[captaint]

I'm with cajun shooter on this one. I skim only after smashing the dross against the side of the pot with a spoon. Amazing how much smaller it gets. Have tried charcoal and it works too, when I take the time to crush it up. enjoy Mike

[buyobuyo]

One thing that I forgot to mention is that I use a butane torch to light the sawdust. If I don't I get a lot of smoke off the sawdust and not being able to see because your eyes are watering while you're casting isn't fun.

[x101airborne]

No, it is not fun. BUUTTT, I leave a paint stick on top of the pot while it heats up. This removes the moisture from it and it is nice and dry when I flux. Saw dust or charcoal works very well to seal the melt from open air. I like to leave the ash on top of the melt when I cast, but I am still learning...... I do not remove the dross. Even when I add to the pot. I just re-stir with the paint stick and keep going.

[williamwaco]

Gear.

For five decades I have used paraffin two to thee times - until crud quits forming. I scrape off all dross until the top of the pot looks like a mirror. I guess I learned this from Lyman but I don't really remember.

Since being on this forum, I have become very interested in the sawdust method. I like it especially because it is the only thing I have found that will "improve" zinc contaminated. I say "Improved" because it reduces it but does not eliminate it.

Here is the problem - and the main reason I quit using it. I find that after adding new ingots to the pot a couple of times, the ash begins to show up in the surface of the bullets.

What am I doing wrong.




Unfortunately the smoke is unbearable to my asthmatic nose.

[Sonnypie]

I use Lizard Litter I got at Petco (http://www.petsmart.com/product/index.jsp?productId=2752164) for my vibratory cleaners.
It is ground up (consistent) English walnut shells. (Hardwood)
I have a plastic scooper like comes in powdered laundry detergent and just sprinkle a nice little pile over the melt.
Then stir gently and leave it on the alloy while I run outside for air. Eventually, I can go back into the shop and resume casting. (I have a vent in the peak)
It leaves a nice char of black sandy appearance that eventually burns down into an ash.
I don't have to flux a lot, usually. And I run clean alloys in my furnace, like Rotometals Lyman #2.
Or Magnum Shot with a 24" x 1/8" piece of Lead-Free solder added for a taste of tin. (Bumpo quickly said, ".31% in a 20# pot." :lol: Note the Point. 31%)
So I don't have a bunch of "Mystery Metal" in the pot.

Works for me! Only 2 alloys, and known flux. ;-)

I tried a little wax once and had a nice bonfire for <1 minute. Woo-Hoo! [smilie=l:

[P.K.]

New guy here and still learning. I'm comfortable with my smelting pot. Pour it all out after smelting. Scrape it and heat it again for casting. I'm using mostly WW so it's maybe hit or miss. I flux and ad tin so my boolits come out pretty good. I punch paper and knock steel, just me. Not like some of the others here who are casting legends. I do like to fool with my alloy a bit but nothing earth shattering. I use the same pot for everything if it's lead. No sawdust. I just drop the burnt matches I've accumeulated over time into the mix, wit a candle stub. Flux and charcoal done. Just brush aside with the dipper and pour.

[geargnasher]

Walnut shells make really acrid smoke, I could be wrong but I think something in the gas is poisonous. Maybe I've sniffed too many lead fumes already! Anyone know for sure?

Williamwaco--Any sort of grease/wax/oil (pumpkin spice candle stubs is a good one) will do a fantastic job of reducing oxides, which is great for clean, pure alloys like foundry-grade stuff, but not so good for actually FLUXING the alloy, removing contaminants like calcium, aluminum, iron (rust), and a whole long list of other stuff that us boolit casters don't want in our metal. This is where sawdust comes in, it does it all, especially for dirty alloy that really needs some chemical cleansing.

As for keeping the junk off the bottom, skim before adding ingots, and make sure you don't scrape the bottom of the pot with a stick, as the tip of the stick will slough ash off on the bottom and it will get trapped under the melt by the alloy's high surface tension and weight. The ash trapped down there will migrate horizontally due to the flow of the alloy to the bottom-pour spout and end up in your boolits. The ash won't get under the melt if you don't put it there in the first place.

Another source of dross inclusions in the boolits is from adding your sprues and culls directly back into the pot during a casting session. As each sprue hardens, the surface is oxidized. This oxide skin is carried to the bottom of the pot (since cooler, solid lead sinks in the molten pot of lead), where the skin gets trapped. The oxides have a much higher melting point than the alloy does, so they will never melt in completely. The only way to get the oxides back into the melt is to reduce them. This is where your wax and sawdust come into play again.

I have finally adopted the technique of adding all my sprues, culls, and ingots back to the pot at once and flux/reduce them really well, leave some sawdust on top, and not mess with the pot again until it's empty. This works much better for me that adding sprues back as I went all those years!

Gear

[bearcove]

Now that you mention it I tend to dump sprues, drips, add a bit of sawdust, stir at the same time. That gives the mold a few minutes to cool while I tend the pot. Then go back to it. I think the worry about oxides on that short of a time frame might not be so important.

At least at the quality level I play at!

[geargnasher]

The oxidation occurs almost instantly. If it's not causing you any problems, don't worry about it.

Gear

[MikeS]

When casting, I add the sprues back in as I go, but I keep a thick coating of Pat Marlin's CFF flux on top of the molten lead, and the sprues sit on top of the CFF. After sitting on top of the CFF for a while they melt thru, and fluxed as they go! :) Most of my moulds have 4 cavities (other than about 3 two cavity ones I still have) so if I don't add the sprues back as I go I think I would empty the pot within a few minutes!

Along with the CFF I also have about the same amount of small animal bedding (pine shavings) that are cut larger than CFF, and I find it seems to last longer than CFF as a cover for my alloy, where the CFF seems to be a better flux for actually reducing the oxides back into the alloy, so I'll flux with CFF (I usually put some on melt in the pot, and once it starts to smoke I'll light it on fire, and stir it into the alloy), then put a bunch of the pine on top, then start casting. Having the thick cover seems to keep the alloy cleaner, it holds in the heat, and gives the sprues a place to sit while they come up to temp so they can melt back into the alloy.

[kbstenberg]

My casting procedure is the same as Mike S's. Only i just use whatever sawdust is present from my last project.

[ku4hx]

Keep in mind that Lyman has recommended this site for casting info. This board has changed a lot of things since 1970, and we now know that skimming that off, is removing tin from the alloy.

I generally don't try and fix what ain't broke. The way I see it for my purposes, if it's floating on the top, it's not going out the spout. And if I push it out of the way when I scoop with a ladle, it's not going in the ladle. That makes the sole source of the tin going into my boolits the melt itself and not the dross floating on the melt's top. ipso facto, get shed of the stuff that's just in the way.

[milprileb]

After sitting on top of the CFF for a while they melt thru, and fluxed as they go!

I am not seeing the logic of the above technique but hey... its a big wonderful world out there.

I use the procedure Gear detailed and frankly, it works for me. Saw Dust has proven (as stated by many on this board) to be a ideal fluxing agent.

What I got out of this thread is the details from Gear about not tossing sprues in as you are casting ( I was doing that) and not using a stick as the ash deposits under the melt (again I was doing that). These points noted and will self correct! Thanks Gear !

[williamwaco]

Walnut shells make really acrid smoke, I could be wrong but I think something in the gas is poisonous. Maybe I've sniffed too many lead fumes already! Anyone know for sure?

Williamwaco--Any sort of grease/wax/oil (pumpkin spice candle stubs is a good one) will do a fantastic job of reducing oxides, which is great for clean, pure alloys like foundry-grade stuff, but not so good for actually FLUXING the alloy, removing contaminants like calcium, aluminum, iron (rust), and a whole long list of other stuff that us boolit casters don't want in our metal. This is where sawdust comes in, it does it all, especially for dirty alloy that really needs some chemical cleansing.

As for keeping the junk off the bottom, skim before adding ingots, and make sure you don't scrape the bottom of the pot with a stick, as the tip of the stick will slough ash off on the bottom and it will get trapped under the melt by the alloy's high surface tension and weight. The ash trapped down there will migrate horizontally due to the flow of the alloy to the bottom-pour spout and end up in your boolits. The ash won't get under the melt if you don't put it there in the first place.

Another source of dross inclusions in the boolits is from adding your sprues and culls directly back into the pot during a casting session. As each sprue hardens, the surface is oxidized. This oxide skin is carried to the bottom of the pot (since cooler, solid lead sinks in the molten pot of lead), where the skin gets trapped. The oxides have a much higher melting point than the alloy does, so they will never melt in completely. The only way to get the oxides back into the melt is to reduce them. This is where your wax and sawdust come into play again.

I have finally adopted the technique of adding all my sprues, culls, and ingots back to the pot at once and flux/reduce them really well, leave some sawdust on top, and not mess with the pot again until it's empty. This works much better for me that adding sprues back as I went all those years!

Gear


Amen to that.

Learned that a long time ago. I drop them in a bucket and use them to "start" the pot next time. They seem to melt faster that ingots.

[Bloodman14]

So, have we quit using kitty litter as a rule? My problem is this; when I flux with sawdust, it seems that a bit of alloy (tin?) gets caught up in the ash (I can see small spheres of shiny metal in the ash). How do I recover that alloy?

[390ish]

You guys leave dross on the top when using a dipper? I don't have a bottom pour. Just ladle around the junk?

[Sonnypie]

Walnut shells make really acrid smoke, I could be wrong but I think something in the gas is poisonous. Maybe I've sniffed too many lead fumes already! Anyone know for sure?

Gear

Actually, they claim all smoke is carcinogenic. (Causes cancer, and bad Ju-Ju.)
Maybe whoever told you that was referring to the tannin acid in Oak?
And I happen to love smoked Salmon. I do my own. I use Hickory.

I did find this MSDS (Material Safety Data Sheet) (http://www.agsco.com/MSDS/msdsWLS.il.092608.pdf) which is a really good indicator for most stuff.
It's what the Government uses to hold your feet to the fire if you hire folks. :holysheep

Now as for some of the other stuff folks add.... (myself included at times) :-( :dung_hits_fan:

[Sonnypie]

So, have we quit using kitty litter as a rule? My problem is this; when I flux with sawdust, it seems that a bit of alloy (tin?) gets caught up in the ash (I can see small spheres of shiny metal in the ash). How do I recover that alloy?

Naw.
But PahLEASE stop using the USED kitty litter. :veryconfu :lol:

Lookie here fellows, if I was that worried, I wouldn't cast at all.
Besides, that blond ahead of you riding the brakes is putting worse stuff in the air than you are casting a few boolits from time to time. [smilie=s:

[TheGrimReaper]

I skim the ash off myself.

[geargnasher]

Sonnypie, Cat Pee makes great flux!! Used kitty litter is a go, but I can't seem to find an MSDS on it :kidding:

Gunnerd, Kitty Litter does absolutely nothing for reducing oxides like the scum that forms when you melt down a bunch of ingots or run the pot too hot too long. It might absorb some impurities, but not sure about that. The only thing it does is protect molten alloy that has already been fluxed, reduced, and cleaned from further oxidation, and insulates the melt from the cooler temps of the atmosphere and thus preserves heat. It's an excellent solution for those who must cast outside in cold weather with a bottom pour.

Milprileb, the technique that was described regarding returning sprues to float on top of sawdust/CFF until melted works fine. I've done it, but it takes a little more finesse. I choose not to do it because it adds one more high lifting motion to the casting sequence.

Gear

[Springfield]

I flux with CFF and/or beeswax based bullet lube. Both will make all the impurities on the top return to the metal if I use enough,sometimes it takes 2-3 stirring sessions with the flux. If I still have silver metal in the ashes I add some more flux until I don't. I add the sprues back into the pot as I cast but I have a 40 lb pot, might work better than a smaller pot. I don't like to leave any flux on top as when I cast 2000 bullets in a session it all ends up in the mix, not on the top, so it isn't doing it's job anyway.

[Bloodman14]

Gear, if I use sawdust or oil in conjunction with the kitty litter, will that work?

[geargnasher]

Gear, if I use sawdust or oil in conjunction with the kitty litter, will that work?

Yes it will. I use diesel fuel salvaged from used filters at work and sawdust when smelting heavily oxidized wheel weights, roof lead, plumbing lead, etc. I light teh diesel as soon as I light the burner, it helps add BTUs to the lead and save propane, plus it creates a very sooty, carbon-monoxide-rich, low oxygen enviroment to help reduce the oxides as the lead is heating and melting. Also boils off any moisture in the pot or metal right away.

Clean ingots don't require such severe fluxing/reducing once in the casting pot, so a pea-sized lump of smelly-good candle and a couple tablespoonfuls of sawdust is more than enough to get the alloy ready to cast. In the end it all comes down to a matter of personal preference, although chemically some things work better than others, regardless of the beliefs of the user.

Gear