A myth of tin separating lead.

[geargnasher]

I've seen the questions asked before, but I might as well be the guy to ask anyway...
Can dross be returned back into the melt or is it simply waste? There's dross, and then there's dross. I don't know what you call it, but the oxide scum that appears after a pot of metal has been melted, stirred, fluxed, reduced, and cleaned should be reduced back in rather than skimmed because removing it changes the alloy composition. I get more consistent boolits from alloy that is constant in both temperature and composition.

If dross is a combination of lead oxide, tin oxide and other 'stuff', can anything useful be accomplished by saving the dross and then returning it to a melt latter?
I've got a coffee can that's about half full of dross. Is it worth mixing that dross into a pot of lead and fluxing the heck out of it, or is it a wast of time? It is always worth trying to save the metal oxides from "dross", and where possible do so before removing it from the pot that produced it. If you have a bunch saved, dump it all into your wheel-weight smelting setup if you have one (i.e. cast iron dutch oven and turkey fryer burner), pour a cup of diesel or charcoal ligher fluid over the dross, and light both the dross and the burner. Stir with a stick until pure metal starts to ooze out, separate that from the ash when the fuel burns off the dross, and you've probably reduced about as much as you can. The metal you reduced can be hardness tested and/or specific gravity tested to get a ballpark idea of it's content, but you can just toss it in with metal from your next casting session to sweeten the tin content a touch.

Isn't the practical conclusion to just have a layer of sawdust on top of the melt (bottom pour)? Works for me.

I don't have a technical backround in metallurgy, although sometimes I wish did. What I DO have is the ability to use resources (not necessarily the internet) to educate my self on any subject within the limits of my intelligence. I was homeschooled until the ninth grade by my parents (one has a master's in Special Ed and the other an MFA and MS in English, both career teachers), and the one thing I was taught to do best was how to teach myself, since no one really knows how I learn better than I do. It amazes me how little people know about things in the world around them because they never realized that it was within their own power to discover uncommon, higher, and specific knowledge about any subject if they would just put some effort into it. You don't have to have a lecturer to learn something. I was formally educated as an engineer and thus have a solid background in physics, mathematics, engineering, drafting, CAD, materials, and process, but that doesn't mean that's all I'll ever know about. I've also been formally educated in automotive service technology since I prefer that line of work. You'd be amazed how little I know about some common subjects, though. Can't know everything!

And for those of you on the spelling/grammar rant, there sure is a large and obvious difference between a request to stop being an apathetic slob with our language and a personal attack. The "glass house" comments always get my goat because those that make them usually function from a victim mentality and are unrealistically sensitive to what they perceive as someone being attacked. But that's just my perception. Wow, two sentences in one paragraph started with conjunctions, I must be really slipping!

Gear

[runfiverun]

carbon type flux and an oxygen free atmosphere.
mainly burning sawdust and some wax on fire is your best bet.
work it smash it stir it, don't try to do to much at one time.

sorry gear couldn't resist.

[rob45]

This has been going on ever sence I started casting my own boolits well over 35 years ago. This is not to prove that I am wright and someone else is wrong. It's just a matter of getting it stright, ie educating ones self. Tin and lead will not and can not separate with the equipment that is avialable to the home caster, and before you get all up set please look up on google this process. Just type in "the process for separating tin from lead". Click on Continus Method of separating tin from lead. The artical is a real good read and the process is quite involved, which includes injecting oxygen and chlorine into the melt and having the melt at a very high degree, stiring the melt quite fast. The equipment that is used probably cost in the thousands of dollars. My guess would be that it is not profitable. Although almost all tin comes from foreign countrys and the price of tin "new supply" is running around $12.00 to $15 dollars a pound. Thats not too far off from the price of silver.
This should ease our minds of worrying about our expensive tin leaving the pot by evaporation or oxydation into drouse.
I certenly hope I have not stepped on anyones feet.

THE HEADING SHOULD HAVE READ:
A MYTH OF TIN SEPARATING FROM LEAD.

Actually, the method to which you refer is a patented process of intentionally removing tin from lead.
For purposes to which this process applies, tin is considered a contaminant in the lead.
Ever wonder how foundries make "pure" lead? This process is but one of many methods used to get there.

We are not foundries attempting to remove the tin; we are bullet casters attempting to keep the tin in there. Since tin is our most expensive component, and our intent is to retain it, we naturally safeguard against the loss of it.

Rest assured, oxidation is real. It will happen anytime our molten alloys are exposed to air. The process can be either benefit or detriment, depending upon your intentions. For purposes of intentionally alloying tin with lead, oxidation is most certainly a detriment.

Once an oxide layer forms on the surface exposed to air, that layer helps to inhibit further oxidation. It doesn't totally prevent it; it slows the process down.
Here is an analogy to understand that statement:
If you take your new "in the raw" carbon steel barrel to your gunsmith, he will be happy to use a "controlled form of rusting" to slow down the tendency to further rust. In other words, he will blue it or rust-brown it.
His methods and equipment will be more costly than simply letting the steel oxidize (rust) naturally, but the results will be more predictable (and certainly quicker) than putting the barrel somewhere and "seeing what happens".


So here are two scenarios:

1. You are operating a foundry where you intend to remove tin from lead. You want to remove as much as possible, and you want the most effective means possible. You realize that tin will oxidize more readily than lead, but you need a quicker, more complete (thorough) process than natural oxidation. You need a process to augment oxidation.

2. You are a bullet caster who wants to alloy tin with lead. You have been constantly experimenting with different percentages of tin in an effort to create the "perfect boolit" for your application. You know that oxidation will occur any time your molten alloy is exposed to air. You also know that tin will oxidize more readily than lead due to the relatively low casting temperature you're using.
You want to combat that oxidation, because not only is your tin expensive, but you have already made a batch of 30:1 alloy, and now you are wanting to test some loads made with 25:1 alloy.
You start thinking to yourself: "I know that gray scum layer on top is helping to prevent further oxidation, but I added exactly eight ounces of pure tin to twelve and a half pounds of pure lead."
"Aw, man! That gray scum might be more tin than lead! How much tin is no longer alloyed with the lead? I'll bet I don't have a true 25:1 alloy any more! I already have a batch of 30:1 alloy; I hope I'm making it closer to 25:1 than 30:1 alloy. Sounds like I better reduce that oxidized tin back into the melt, just to be sure. And once I put the tin back in, I probably need to keep it in there, too.


Conclusion: Simply because a specific process has been developed to augment oxidation does not mean that oxidation ceases to occur when said process is not utilized.

[45-70 Chevroner]

It looks like I'm going to have to eat crow. It apears that the general consensus is that I am wrong. I do think that after adding tin ( I actually use very little) to the melt and fluxing and for the time it takes to cast up a batch of boolits, say 20# I can't see any difference in my boolits from beginning to end. Maybe that doesn't mean my tin has not depleated or oxidized or migrated to the surface. I will probably continue to cast the same way I have been doing it for seems like eons. As for grammer and spelling, I"m a pretty big guy and I have big shoulders so I can take a lot of criticism. I know for sure that I make a lot mistakes as to both grammer and spelling. Like one gentleman (geargnasher)said in his post (be carefull of the glass house effect). I have personally corrected people on this site, but I certinly had no intention of trying to embarrass someone. As for spelling the dictionary is my best friend. I use it quite often and obviously not often enough. Truthfully CROW does not taste very good.

[felix]

Consistent boolits are easier to make when PID controllers are used to keep the lead at a constant temp. The best setup would be to include a seperate PID for a hot plate which would warm the mold to a set point before using. The boolits will be consistent if the lead is at a consistent temp from start to finish, and sprues are NOT put back into the pot throughout the session. Eliminate all boolits that vary in weight according to mold cavity. The variance should be zero per cavity for at least 80 percent of the boolits. If not, change the lead composition or wait for another day to cast. Humidity and pressure does make a difference that can be measured via boolit consistency. The whole idea is to keep the lead as a saturated alloy with ALL constituents, and allowing the excess to migrate to the top before serious casting. Very hard to do when copper is intentionally desired within the mix because copper just won't stick within the lead solution using home equipment. Copper inclusion requires constant stirring, it appears. ... felix

[runfiverun]

felix i think tin helps keep copper in solution too.
airc between what i tried and leftiye tried we come up with 10% tin to 3% copper in an alloy.
try keeping that all fluxed in and protected.
i used a barrier of marvelux and high casting temps.
i din't really come up with a good use for the alloy though,except to try some higher velocities in the rifles.

[44man]

I ladle cast so I do not want a bunch of crud on top. I flux often and get very little dross in my can. I can cast for a week and will have very little in the can.
I have dumped it back in the pot to flux again and still come up with the same amount in the can.
The only lead I don't worry about flux with is pure and I still do not get that much in the can, maybe a little more then from my alloys because I run pure hotter.
I do believe tin can be lost but I have never been able to recover any usable metal from dross.
Someday I will measure the weight but I don't expect much change.

[geargnasher]

44Man, you only remove the oxides with the dross if you haven't reduced them back in before skimming the true "dross" or non-metal trash from the melt. What you're calling "fluxing" is probably more of a reduction process which yields only ash and mineral impurities, and that is what ends up in your dross can. My dross can if full of brownish-grey ash with occasional specks of metal oxide and charred sawdust bits, no clumps of metal oxides in the dross.

Gear

[felix]

5R5, you are correct. Tin and copper do have some affinity for each other, and others like arsenic besides tin prolly do too. Yes, copper is for toughening up an alloy and seems to make boolits hold the faster twists mo'betta' without distortion. However, accuracy does suffer when the copper is not applied consistently, no matter when the boolits weigh exactly the same. Might have something to do with the pot's spout not being consistent before a drop. I typically drop some alloy before applying the mold to the spout, especially when copper is involved. That seems to help some in the accuracy department. ... felix

[Rocky Raab]

Consensus doesn't make reality, chevroner. Not for a flat earth, not for man-caused climate change and not necessarily for bullet casting.


(If words and typos don't matter, just write to tell your mother you are interested in incest - when you meant insects.)

[nanuk]

so can felix make me a PID controller? or does someone make them for sale?

cause I have little experience in that area, and if I tell my wife that I'm going into the other room to play with my PID.... Well, I just won't go there.

[45-70 Chevroner]

Rocky Raab: I'm not realy sure what conclusion has been arrived at here but it sure seems that there are some diverse opinions about the subject.

felix: I'm not making fun of you but what is, are, PID controlers. I realy hate some of these abbreviations because I'm not in the know or maybe I just don't get it.

[sundog]

Felix, over the last few days I have been casting with a 1# bar of our #5 alloy (made with your copper babbit) per roughly 5#s of WW and 5# of range scrap. Did a batch of NOE 225-60-RN (the new mould just delivered - nice boolits btw) and SAECO #301 for 2 days in a row, a couple hours at a time. I just wasn't getting enough oxidation on the top of the melt to worry about loosing anything. I drop sprues back in as I go so it stays mixed. Got some really nice boolits! The melt stayed together quite nicely and poured very well at about 700dF. I'm willing to bet that a high dollar assay won't find find much of a difference between first and last boolit per potful. My experience is that the rifle can't tell the difference and that's where it really counts. Anyway, unless you are competing for a world record or dollars, it makes no difference.

[HangFireW8]

The best setup would be to include a seperate PID for a hot plate which would warm the mold to a set point before using.

I have to chuckle... I built a half-wave rectifier so I could run my 1000W mold warmer hot plate at 500W continuous instead of 1000W cycling, and caught hell for it on this forum because it was deemed unnecessary by someone here....

-HF

[dualsport]

I don't have a technical backround in metallurgy, although sometimes I wish did. What I DO have is the ability to use resources (not necessarily the internet) to educate my self on any subject within the limits of my intelligence. I was homeschooled until the ninth grade by my parents (one has a master's in Special Ed and the other an MFA and MS in English, both career teachers), and the one thing I was taught to do best was how to teach myself, since no one really knows how I learn better than I do. It amazes me how little people know about things in the world around them because they never realized that it was within their own power to discover uncommon, higher, and specific knowledge about any subject if they would just put some effort into it. You don't have to have a lecturer to learn something. I was formally educated as an engineer and thus have a solid background in physics, mathematics, engineering, drafting, CAD, materials, and process, but that doesn't mean that's all I'll ever know about. I've also been formally educated in automotive service technology since I prefer that line of work. You'd be amazed how little I know about some common subjects, though. Can't know everything!

And for those of you on the spelling/grammar rant, there sure is a large and obvious difference between a request to stop being an apathetic slob with our language and a personal attack. The "glass house" comments always get my goat because those that make them usually function from a victim mentality and are unrealistically sensitive to what they perceive as someone being attacked. But that's just my perception. Wow, two sentences in one paragraph started with conjunctions, I must be really slipping!

Gear

I tried, I just couldn't resist. What is the large and obvious difference between calling someone an 'apathetic slob' and a personal attack? Sounds kinda cranky to me. Just for the record, all you grammatically challenged members out there go ahead and peck away, I don't care what your grade was in English class. If you can get close I won't check your spelling.

[felix]

Yeah, Corky, 1 pound of that brick that you used should be about perfect for that 20 pound pot full of obvious mixture. Should that brick make the total mix have about 1/2 percent of copper? That amount of copper should find something to hold onto before rising out of the mix with constant mixing. Like you say, looking at the top of the melt is sufficient for a determination anyhow. ... felix

[acemedic13]

The " W " key is right next to the " E " key.
A typo is a bit different that someone going against the grain with their lecture and not even bothering to use proper language. It sorta detracts from the credibility.

I think you meant "Than" instead of "That" in this post. I know what you meant, but I thought I would point it out....JK man..... You're definataely entitled to your opinion. You go bro!

[felix]

HangFire, most of us do not use copper (intentionally) in a mix. Small impurity amounts can be ignored. Larger amounts require special attention to the mix at all times which includes all ambients surrounding the entire setup. ... felix

[felix]

Medic, you are definitely defiant if you do not understand the difference. ... felix

[sundog]

With copper (and tin), when you get it right, they make 'clinky' boolits when air cooled. That #5 alloy that Felix and I made several years ago will NOT pour a boolit by it self - it sheets and makes voids, it does not fill out well. When stretched with additional lead, it does very well. Just gotta get close. You know when fill out is working well.

Thanks for the lesson Felix years ago. It took well.