RicinYakima
High Steppes of Eastern Washington
Here in the desert, there is not enough moisture in the air to disperse the HCl (hydrochloric acid) from the Marvelux fumes. Everything rust like crazy if you use it here.
Is Flux important and what can I use?
- Thread starter burbank.jung
- Start date
Ian
Notorious member
That will cause oatmeal, too, due to crystallized antimony precipitating out of solution at low temp with not enough tin to make the bimetallic/intermetallic Sb/Sn. Repeatedly ladling over a hot pot will build oxide meal on top since the oxides melt at something like three times the temperature of the molten alloy. A reducant will blend the oatmeal right back in.
Most people add a lot more tin than I do.
RicinYakima
High Steppes of Eastern Washington
That would be me, since I have a lifetime supply of tin bought cheap 20 years ago. Bought 50 pounds of 50/50 from a hot rod builder for $20. Lead sleds don't exist anymore, everything is plastic.
All of which reminds me that I need to melt down a bunch of wheel weights again. I SWEAR I just DID that!
In 1990 or '91?
I have a 55-gallon drum full of wood shavings/sawdust, so that part's covered, but I learned over time, that if you let your wheel weights "age," you should be able to get more bullets out of them!
If my extrapolation is correct, I should get twice as many bullets out of each bucket of wheel weights as compared to what I got in the early nineties, because those buckets now easily weigh twice as much as they did when I stuck them under them bench thirty years ago! Talk about a return on one's investment!
In 1990 or '91?
I have a 55-gallon drum full of wood shavings/sawdust, so that part's covered, but I learned over time, that if you let your wheel weights "age," you should be able to get more bullets out of them!
If my extrapolation is correct, I should get twice as many bullets out of each bucket of wheel weights as compared to what I got in the early nineties, because those buckets now easily weigh twice as much as they did when I stuck them under them bench thirty years ago! Talk about a return on one's investment!
Mitty38
Well-Known Member
I never flux in the bottom pour pot.
I just double flux my scrap lead and base alloys, with pine bedding, when making.
Then pour thru a stainless 25 micron foundry filter. Thing is you need two cast iron or ceramic pots-crucibles, to do this. You need to pour pretty fast, especially if you are laddeling from one pot to the other. So splash protection is nessesary. I make a 50 lb pot. Or less,at a time, and pour from the pot to a crucible.With the filter fastened to the top of the crucible.
To be safe. I also wear chaps and a leather apron, shoes etc. when filtering.
The filter, of course I got mine from trim pieces left when they install filter in our pour troughs at work. Before they went to ceramic foam.
The filter catches iron, calcium, sand, and leftover suspended carbon from the saw dust.
You will not believe how much crap you can catch with a filter. I do this with everything but my tin.
Then add tin as nessesary, or alloy in a separate step later and run a little bees wax thru it, as a final clean up.
My lead, and pre alloyed is super clean when cast to ingot, then put in 18 lb boxes. Perfect for Lee 20 pounder.
When I bottom pour, I just throw a little paraffin on top. Let it catch fire, and leave a film on the top.To hold the tin in the mix and keep the top of the mix from oxidation.
I also use the Parrafine to help stir the tin back into the mix, that still manages to sometimes float to the top.
I just double flux my scrap lead and base alloys, with pine bedding, when making.
Then pour thru a stainless 25 micron foundry filter. Thing is you need two cast iron or ceramic pots-crucibles, to do this. You need to pour pretty fast, especially if you are laddeling from one pot to the other. So splash protection is nessesary. I make a 50 lb pot. Or less,at a time, and pour from the pot to a crucible.With the filter fastened to the top of the crucible.
To be safe. I also wear chaps and a leather apron, shoes etc. when filtering.
The filter, of course I got mine from trim pieces left when they install filter in our pour troughs at work. Before they went to ceramic foam.
The filter catches iron, calcium, sand, and leftover suspended carbon from the saw dust.
You will not believe how much crap you can catch with a filter. I do this with everything but my tin.
Then add tin as nessesary, or alloy in a separate step later and run a little bees wax thru it, as a final clean up.
My lead, and pre alloyed is super clean when cast to ingot, then put in 18 lb boxes. Perfect for Lee 20 pounder.
When I bottom pour, I just throw a little paraffin on top. Let it catch fire, and leave a film on the top.To hold the tin in the mix and keep the top of the mix from oxidation.
I also use the Parrafine to help stir the tin back into the mix, that still manages to sometimes float to the top.
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Mitty38
Well-Known Member
There are several types of casting filter screens, and filters available. Mostly for aluminum, brass and bronze.
Do not know if there are any specifically designed for lead. But the filter material I got for aluminum, works just as good for lead.
We filter all medical equipment and all food grade aluminum alloy at work.
Filters and screen are available in ceramic, fiberglass, stainless.
We switched from a stainless screen set up, to ceramic at work with the aluminum. Because the stainless would degrade and get in the aluminum, if exposed to the molten metal too long. So it needed constantly switched out, while pouring. Plus we started having trouble getting the stainless screen in the size and thickness we needed. "covid troubles"
So when we finally used up all the stainless at work, they let me have a couple "small" scrap pieces that were left.
Lead is a cold enough pour, that it does not degrade the stainless scraps I use. So works for me.
I use 25 micron mesh, But If looking for a filter. 50 micron or less would probably be fine. Or a 40 ppi ceramic.
I catch a lot of carbon and rust. Started doing it when I started working with the .223 mould. Cut my weight culls by about 15%.
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Snakeoil
Well-Known Member
Now that is truly interesting. I don't think I ever would have envisioned lead flowing thru a 25-micron filter screen. Is it a screen in the sense that is it a woven fabric or is it some type of micro-pierced sheet metal? I imagine the lead has to be pretty hot to keep the screen hot so there is sufficient flow.
I'm still struggling with trying to envision lead going thru a 25-micron screen.
I think a decent setup based on what you described, is two cast iron Dutch ovens on propane burners with a frame over the receiving pot to hang the melt pot to facilitate pouring. Just the thought of pouring molten lead from one pot to another sends a chill up my spine. The weight has to make it hard to control so that framework to hang the melt pot better be strong and stable. I guess if you do it for a living, it's second nature.
I'm still struggling with trying to envision lead going thru a 25-micron screen.
I think a decent setup based on what you described, is two cast iron Dutch ovens on propane burners with a frame over the receiving pot to hang the melt pot to facilitate pouring. Just the thought of pouring molten lead from one pot to another sends a chill up my spine. The weight has to make it hard to control so that framework to hang the melt pot better be strong and stable. I guess if you do it for a living, it's second nature.
Mitty38
Well-Known Member
It is a woven type screen. Made up of 3 layers, large weave to tight weave. Each about twice as thick as your average window screen.
I keep a rose bud torch aimed at the screen while pouring.
I use a turkey fryer and get the lead pretty hot.
I probably separate a slight amount of tin when I do this. But I heat back up and do the alloying after the filtering.
The receiving pot is heated that the screen is put down into. Pour pretty fast. I usually stop half way thru the pour and change screens because it does plug up.
Probably going thru way too much work to get 15% less culls. Since major occlusions can be detected by weight. But that's just me.
When I am done I flip the used screens over. Then clean by melting the caught lead along, with the crap, out onto a pan, with a rose bud torch. Then throw it in my dross can.
I can not get pewter to filter thru this because it is just way too cold. I haven't given it much of a try because pewter is pretty clean anyway.
25micron is probably a bit excessive. Could probably get by with twice that or more. But it is what I obtained.
Would love to get a hold of some ceramic foam filters of different porosities to play with.
I keep a rose bud torch aimed at the screen while pouring.
I use a turkey fryer and get the lead pretty hot.
I probably separate a slight amount of tin when I do this. But I heat back up and do the alloying after the filtering.
The receiving pot is heated that the screen is put down into. Pour pretty fast. I usually stop half way thru the pour and change screens because it does plug up.
Probably going thru way too much work to get 15% less culls. Since major occlusions can be detected by weight. But that's just me.
When I am done I flip the used screens over. Then clean by melting the caught lead along, with the crap, out onto a pan, with a rose bud torch. Then throw it in my dross can.
I can not get pewter to filter thru this because it is just way too cold. I haven't given it much of a try because pewter is pretty clean anyway.
25micron is probably a bit excessive. Could probably get by with twice that or more. But it is what I obtained.
Would love to get a hold of some ceramic foam filters of different porosities to play with.
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Mitty38
Well-Known Member
Man did I unintentualy Drift this thread.
To the OP sorry for that. Do not worry about the filtering part. You won't need to do it.
I only do it because I work with some pretty nasty scrap. And some pretty small cast plane base bullets, in an AR15 close to full velocity, where any factor removed is a plus.
Also, I am a melt shop worker by trade. I am their material analyst. Plus general go to guy. So I have access to a lot of stuff.
Plus I am a little anally attentive.
To the OP sorry for that. Do not worry about the filtering part. You won't need to do it.
I only do it because I work with some pretty nasty scrap. And some pretty small cast plane base bullets, in an AR15 close to full velocity, where any factor removed is a plus.
Also, I am a melt shop worker by trade. I am their material analyst. Plus general go to guy. So I have access to a lot of stuff.
Plus I am a little anally attentive.
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burbank.jung
Active Member
When casting ingots, I'm removing copper jackets and light powder that's like dirt. Sometimes I pickup lead but only a little. As soon as this slag is removed, I empty enough of the pot to fill my ingot mold
My reply was in response to this. If you're not using flux my reply is quite accurate.
burbank.jung
Active Member
Bret, after reading the recommended articles, the flux seems to be removing the oxygen to change the oxide to a metal that can be mixed back into the molten lead. What about the lead in the bottom of the pot. What impurities are there that need to be removed? Or from the stirring, are the impurities being stirred to the surface?
burbank.jung
Active Member
So, clarify this for me. You don't necessarily flux once. As soon as you notice a film or oatmeal build up on the surface, you flux to remove the oxide and keep the alloy consistent.
burbank.jung
Active Member
What is this beard thing you guys are talking about? Is it a buildup of some kind on your ladel?
No! Read the articles by Glen Fryxell posted in this thread. You do not want to remove, you need to reduce. Glen explains this very clearly.burbank.jung
Active Member
I must have missed that. Thanks.
CWLONGSHOT
Well-Known Member
Emmitt that filtering process would make a dandy video!!