"Burning Off Tin"????

[BruceB]

The subject came up on another thread, and I think it deserves its own separate discussion.

Those who've been around since the old days of Shooters'.com are well aware that I have a tendency to test out things that "everyone knows", just for my own edification.

Some years ago in the Territories, a friend and I tested this process of "burning off tin" for ourselves, mostly because we were familiar with the concept of "ALLOYS" and failed to see where this tin would manage its escape. He had a pot from a printer's shop that went up to 1000 degrees Fahrenheit and held about forty pounds of linotype.

We put a carefully-weighed (lab scale) twenty-seven pounds of pure lead in the pot, followed by an equally-carefully weighed three pounds of pure tin. Note that this is what we considered to be a 1-in-10 alloy BY WEIGHT...that is, ten percent of the melt was pure tin. By VOLUME, of course, the ratio is different.

Anyway....

After the mix had melted and mingled, we cooled the pot to room temp and made a mark precisely one inch above the frozen surface. We then filled EXACTLY that one-inch of volume with industrial powdered graphite, to keep the mix from oxidizing unnecessarily by air exposure. (Graphite makes an awful mess. I'd try kitty litter, next time.)

The pot was cranked to 900 degrees and left there for eight hours. This is well above the temp quoted as where tin starts "burning out".

Findings, from a rather crude experiment: There was NO DECREASE in the volume of alloy contained in the pot, and there was NO DECREASE in the weight of the metal in the pot. Ergo, the tin was still in there.

I've thought about that experiment quite a bit in the intervening years, and have yet to find fault with the basic premise, i.e.: if one takes a known quantity of a substance and heats the snot out of it for 'x' time, and the known quantity has not changed in weight OR volume, then nothing is getting "burned out".

I've also seen published experiments by others attempting to test the "separation by gravity" of elements in the melt, meaning that the lighter tin and antimony were thought (by some, at least) to float to the top in the absence of any stirring or other disturbance.

The error in that thinking was proven by simply casting bullets from the bottom-pour pot, after it had sat fully heated for a period of some hours, allowing the metals to "separate", if in fact they were going to. The pot was then emptied by casting bullets, without disturbing it in any way. The bullets were weighed in order of casting on a very accurate scale, and the conclusion was drawn: there was NO difference in weight between bullets cast from the "bottom" of the melt when casting started, and bullets cast from the "top" of the melt, as the pot emptied. Obviously, if separation had taken place, the last ones cast would be lighter due to higher tin and/or antimony content. Therefore, the makeup was consistent from top to bottom, and NO SEPARATION BY GRAVITY had taken place.

This should get the ol' juices stirring!

[44man]

Bruce, I agree with you. I don't think there is any way to seperate the alloys once melted together. The only thing I ever heard was that some tin can stick to the dross on the top and will be removed unless fluxed first. Probably where the idea of the tin going to the top came from. I have even said it myself but never meant that the tin rose up in the lead. I never stir my lead until it needs skimmed and fluxed. I never flux pure lead. I do flux my hard alloys and 20 to 1 mix because I don't know if the dross has collected good metals.
I don't think there is any way to cook off alloys with a pot or stove either. None will get hot enough. Lead danger is only from the dust from dross or scrapings on the side of the pot. Just have to wash your hands after handling boolits and ingots. Don't lick your fingers or pick your nose!

[felix]

Seperation of elements can and will occur during heating and cooling, but only when the composition is not a happy one. I know this is a bad choice of words, but an example of unhappy alloys are those of the common babbits. There are special fluxes and techniques for keeping them relatively happy when certain instructions are followd to a tee. The vendor of the babbit typically has a how-to sheet based upon the application sold into. ... felix

[JohnH]

You'll find no arguement from me. What often fails to be described is what occurs to lead/tin/antimony alloys when the surface is constantly disturbed by the dipper when using this method to cast. The dipper constantly disturbs the surface, exposing new metal to the oxygen in the atmosphere. I'm not sure the chemically disinclined appreciate fully the corrosive power of oxygen, and when seeing the continued growth of oxidized metal atop the melt, as a result of this constant oxygen presence, it is easy to conclude that something is seperating from the melt. It is also easy to conclude that tin being lighter than lead, it is the tin seperating. If fluxing is not complete, then there is in fact some metal being removed from the melt when the slag is cleaned off, but it is a oxide of the alloy, not of any single part of the alloy.

What seems to escape many is that an alloy is just that.... two or more metals in solution. They bind with one another at a molecular level and cannot be seperated, at least not by means availlable in a garage foundry. (Yes, we have and operate foundries and are metal smiths in case you've not ever thought of yourself as that :) ) Solutions and compounds are different in one significant way, the components a compound will seperate. The proof that we are working with solutions (alloys) and not compounds is that on cooling our boolits don't fall apart. If we didn't have a true solution, our boolits would seperate into their base metals on cooling. That would be quite useless.

Methinks it was this chemical/metalurgical ignorance that fed and continues to feed the ideas that give life to such silly ideas that tin will seperate from the alloy. Seeing it in print by everyone from an exalted gun magazine writer to Lyman doesn't do anything to increase the real knowledge of casters, and on at least one occasion I was reminded that since Lyman contradicted me I didn't know what I was speaking of. I've since quit speaking to this subject on the web, I've no axes to grind and I'm perfectly comfortable allowing the ignorant to remain so.

Thanks Bruce for bringing this up again. It reinforces the need for a manual that speaks to the metalurgy of lead alloys, and what happens chemically and metalurgically with each of the methods we use to cast and what fluxing really does.

[Bass Ackward]

I recieved a lot of linotype over the years because the local news paper did not have the means to reconstitute the mix with enough consistency that after so much use it failed to meet their uses. One of the local steel mills here used babbit just once. Because they did not understand how to flux it properly. In both cases, tin was seperated from the initial solid state. The biggest hang up amongst casters is in the term burnt off. It is a user term not a scientific one because no loss comes until you heat and thus liquify it.

That is the advantage of a bottom pour procedure and why it actually came about. Place any barrier on top to seal against oxygen and oxidation seperation stops. And bullets will remain the same from top to bottom. Laddle from that bottom pour pot and you will have a different story. Remember, the idea for bottom pours came into vogue when high tin content mixes were the standard.

All lead should be fluxed for removal of debris whether it has tin or not. Because of how lead is handled and recycled today, I prefer to flux.

[felix]

JohnH, good intro. Now tell us about slush stage, and what goes on in that time period. A true solution will have zero slush time? ... felix

[Four Fingers of Death]

I have only ever used my Pro Melt to melt down WWs, etc and have made my ignots this way. Probably not a good practice, throwing dirty metals in to the Pro Melt, but I have never had trouble with the spout blocking, so it can't be too much of a problem. When I flux sometimes and get the metal nice and clean, I sometimes get a 'shaded' covering on the metal, which when skimmed off looks like crinkled up aluminium foil. I always try fluxing this back in without much sussess. This doesn't happen often, but worries me when it does. As most of my casting so far has been for handguns, which is not an exact science by any means, I kick on with it.

[Dale53]

BruceB;
Since I am the one who made the statement on another thread, I will defend it. As I have stated before, I am NOT a metallurgist, but I was quoting Dennis Marshall, who IS a mettalurgist. The difference between my comments and your experiment is:

>>>We then filled EXACTLY that one-inch of volume with industrial powdered graphite, to keep the mix from oxidizing unnecessarily by air exposure.>>>

"In as little as 30 minutes, the majority of tin is drossed off at 1050 degrees". This is page 48, column two in the Lyman Cast Bullet Handbook, third edition.

He explained how to control that with a deep film of Borax over the melt. You used graphite which did the same thing.

I essentially stand by what I said. I also believe you. Having a barrier to oxydation is the key in this particular case.

Dale53

[David R]

I have only ever used my Pro Melt to melt down WWs, etc and have made my ignots this way. WHADDYANUTS?? Do you have something better than a pro melt to cast with ? :)

Slag, or dross is why I stopped using a ladle. PIA! Bottom pour all the way with kitty litter.

I have been pouring boolits for 20 years, and this year I learned about the kitty litter. I spend a lot less time fluxing and skimming. More time pouring. I use a Pro Melt.

David

[utk]

Excuse my lack of words, I'm a Swede and often do not find words for what I want to say. Anyway:

I've read that tin oxidizes more easily than lead.
And therefore, the gray scum we find on top of the melt is mostly tin oxide.
In that case fluxing would be extra necessary in order to reduce the tin oxide back into pure tin. Added carbon atoms from the flux combine with the oxygen atoms from the oxide, resulting in pure tin + carbon dioxide.
The tin content is often low, making it a "rare" metal, worth fluxing for.

Have I gotten it wrong?

[felix]

Urban, you got it right! ... felix

[Bret4207]

My only thought on this is that the tin content is usually less than say 4% of the mix. Given that, how would MORE tin oxidize than lead?

[felix]

Tin is more reactive than lead with oxygen? Possibly. Need to go to the books for that one, but I'm too lazy right now. Time, pressure (weight), heat (agitation) all enter the equation at the same time. ... felix

[44man]

OK, that makes more sense then tin sticking to the dross.

[LAH]

Quote: I've read that tin oxidizes more easily than lead.
And therefore, the gray scum we find on top of the melt is mostly tin oxide.
In that case fluxing would be extra necessary in order to reduce the tin oxide back into pure tin.>>>>>>Quote

I've used melt covers of sawdust. This worked fine. I first fluxed with a plenty and left the covering, not skimming. This seemed to work fine. When the casting stopped I did away with the cover and added fresh saw dust the next session.

Once I started casting for hire I changed to NEI flux. Once the melt was up to temp I would flux. Using 44 & 45 caliber handgun moulds I would add an 8 pound block of alloy each half hour. This alloy was preheated on the pot for the half hour. 15 minutes after adding the alloy I would flux.

In a word I added alloy each half hour and fluxed each half hour. The surface of the melt would become somewhat grey. The flux would make it bright again and leave a fine dust on the melt which I would skim every 3 or 4 flux.

Please understand I know nothing about metal or alloy though I've cast bullets for 30+ years and I both gas and electric weld. I'm just posting this to add what I've noticed casting..........Creeker

[JohnH]

Felix, that prolly sounds like I know more than I do. There is only one true eutectic lead/tin/antimony alloy and that is linotype. It has zero slush period. The zero slush was one of the reasons for its use as a type metal. It is also one of if not the lowest melting point lead alloys... 465 dF I believe it is. I don't know how much tin will actually alloy with lead. We know at least at 1 to 1 (50/50) After that, I guess we would be properly talking a tin/lead alloy. I don't know how much antimony will alloy with lead or with tin, but it seems that I remember that antimony doesn't truly alloy with lead, but rather the two form an intertwining lattice of their molecules, and what is happening in the slush stage is the two finding thier "equilibrium"; the greater the antimony content the longer the slush period. An interesting peice to know if one is quenching for hardness, because the sooner one can get a boolit quenched (preferably while it is still in slush) the harder it will become, but don't forget the arsenic required for this.

I think it is also important to remember is that tin and antimony do form a true solution, the metal is commonly called pewter. It may be for that reason alone than tin in combination with antimony and lead is always a good idea, but the practice of lead/antimony boolits made from straight WW, not to mention 22 rimfire bullets would seem to suggest that there is some room for play between alloy theory and boolit practice.

Dale53, Not slammin' you, but Dennis Marshall..... What hell kind of casting temerature is 1050 dF? Who casts boolits at those kind of temperatures? I've no doubt that Marshall is correct, but if his point is to speak to the loss of tin from a melt due to heat, I think he should also tell us what kind of loss will be seen at 750 dF and less, as most if not all our casting is done at such temperatures. Marvelux is Borax by a different name. The stuff is hyrdoscopic and it has an oxygen component to boot. If the whole point is to creat an anerobic condition (the absence of oxygen) Why tell us to pour Borax onto the melt when that creates exactly the kind of condition we want to avoid? And have you ever dealt with that goo? I'd rather use nothing was the conclusion I came to very quickly after I tried that one.

I remember reading the article you reference, reading and rereading, and most of it was written for metalurgists, not laymen like ourselves. I'm an avid reader and have no trouble with college entry level writing. I'm certain that I can read better than 95% of the current crop of high school graduates that are college bound. Marshall/Lyamn did us no big service with that article, I'd bet not 1 in 30 who bought Lyman Cast Bullet Handbook #3 had a reasonable understanding of what he said or how to use it to improve their casting methods. In fact, I bet most experienced casters bought it for the data and ignored the rest. It was only newbies like myself that read it at the time and thought we'd learned something.

In fact, Marshall double speaks himself when addressing fluxing, at once saying there is no need but then saying we continue to do so if only out of familiarity and comfort. That's just stupid as hell. If you are going to teach something, teach it. If you are going to lead into new territory, lead. But don't talk out both sides of your mouth. I suspect Marshall was making an overture to the tradionalists, I've people who religously flux everytime they see dross forming even when using a bottom pour method

All this goes back to the heart of what I was said, I've learned more here and by forgetting what Lyman/Marshall/Venturino/Seyfried and a host of others I've read over the years. The need for a real casting manual; such that a complete idiot like myself can take and make boolits with confidence and be able to speak to the art with others without sounding like a fool is great indeed. And a chapter devoted to the metalurgy of our alloy(s), written in plain terms that don't require an engineering degree to make sense of should be a to priority.

OK, rant over.

[Dale53]

JohnH;
Some of what you say definitely has merit. However, you have to understand that engineers talk "engineering" and metallurgists "talk the talk" . It is extremely unlikely to find a person with a Specialty field that does not. That's just the way things are.

Actually, I got quite a lot out of the article - I learned that 750degrees is better than 1050 degrees :mrgreen: (that was his whole point). Of course, my favorite cast author is E.H. Harrison. Extremely bright, well educated and a fellow that really made things easy to understand. His articles re-inspired me to really get into casting (I have cast bullets since I was a teen ager and THAT is a long time ago:) .

Also, you must remember that the only authorities that we had came from books where you couldn't ask someone to clarify. We have a heck of an advantage with the internet, these days.

Dale53

[Bass Ackward]

What hell kind of casting temerature is 1050 dF? Who casts boolits at those kind of temperatures?


John,

I believe Dan had to quit cutting certain large size molds because guys were molding at and over 1000 degrees to get fillout on large diameter slugs. This was causing warpage of the blocks and thus customer complaints. So there are a lot of guys casting hot. Especially the pure lead boys who are not adding any tin.

Remember, back when Marshall wrote a lot of his work, casting was a pot on the stove. How did most folks know they were running 650 or 950 since most casters wouldn't splurge for a thermometer? And if you were stiring the pot while molding, removing a hot dipper and replacing it with a cold one. And then you stopped for a second, to do something else, how high did the temperature go until you started again?

My Lee pot will go to 1100 at the highest setting. But I do have a thermometer.

Some of those articles were written to inform and frighten guys into being careful. Kind of a CYA thing too.

[454PB]

I once had a bunch of what I "suspect" was zinc contaminated lead alloy. I melted a pot full, cast some rather crappy boolits, then left the pot (Lee 10 pounder bottom draw) turned on for 3 days. Each evening I'd go out and flux the mess and cast a few boolits. I was trying to "burn off" whatever the contaminate was. This experiment failed, the alloy was no better or worse after 3 days.

Bruces experiment verifies what I've always practiced. I've said here before that I always use a bottom draw, flux well with Marvelux and leave the dross on the surface. The dross serves the same purpose as cat litter, as an oxygen barrier. I get zero slag inclusions, very lttle weight variation, and no problems with the spout plugging.

[montana_charlie]

Each evening I'd go out and flux the mess and cast a few boolits. I was trying to "burn off" whatever the contaminate was. This experiment failed, the alloy was no better or worse after 3 days.
I once thought that, if kept in the molten state long enough, the various metals would separate by weight. After reading the theories/knowledge/guesses of others, I am less inclined to believe that.

However, I am still under the impression that there is 'fluxing'...and then there is whatever-you-call-it when using Marvelux and similar things.

Marvelux/borax/kitty litter substances insulate the melt from oxygen, which reduces or eliminates oxidation.

'Fluxing' (if I understand correctly) is a dual process of 'un-oxidizing' metals which have done that...and then blending them back into the alloy.

If you 'fluxed the mess' every evening, it would seem that you were reversing any separation which may have occurred.
CM

[buck1]

I once had a bunch of what I "suspect" was zinc contaminated lead alloy. I melted a pot full, cast some rather crappy boolits, then left the pot (Lee 10 pounder bottom draw) turned on for 3 days. Each evening I'd go out and flux the mess and cast a few boolits. I was trying to "burn off" whatever the contaminate was. This experiment failed, the alloy was no better or worse after 3 days.

Bruces experiment verifies what I've always practiced. I've said here before that I always use a bottom draw, flux well with Marvelux and leave the dross on the surface. The dross serves the same purpose as cat litter, as an oxygen barrier. I get zero slag inclusions, very lttle weight variation, and no problems with the spout plugging.
I dont think Zink "burns off" but its the tin that is said to.
To remove zink a low temp skim is what i hear works best.

BruceB, I must agree with others , the graphite would seemingly give the needed carbon to keep the tin mixed.

JohnH, So if I use LINO there should be NO gray film forming on my pot?? If there is it will be a exact coppie of the alloy?

I am in compleete agreement with Felix.

Untill someone takes the gray film and alloy to a lab to be checked before ,during and after casting, fluxing, its ALL opinions isnt it??
.....Buck

[montana_charlie]

Untill someone takes the gray film and alloy to a lab to be checked before ,during and after casting, fluxing, its ALL opinions isnt it??
Probably...and here is another...
I hope this guy is right because I can understand what he says, and it kinda goes with what I have long thought.
http://www.lasc.us/FryxellFluxing.htm
CM

[BruceB]

Getting back to that experiment: the graphite, as a porous and lightweight mass ON TOP OF THE MELT, would not be getting mixed into the molten alloy. It would largely prevent oxidation by denying air contact with the metal, but it would not form an impediment if the metal was "gassing off", as I would assess the reaction if tin was in fact getting "burned out".

Gents, an "alloy" is a molecular bond between the metals. You do NOT have tin and lead in a free state available for separate oxidation or burning-out. What we have is a lead-tin ALLOY, and if anything oxidizes it is the ALLOY being oxidized, not just one of the elements contained in it.

I would expect a chemical analysis of oxide from a potful of bullet metal to contain just about the same proportions of the elements as the original contents of the pot contained.

Just thinking about fluxing, I recently started using wooden dowels for that job, thanks to waksupi's writings here at Cast Boolits. It's a great way to get carbon right down into the bottom of the melt, and the dowel makes an excellent stirrer even while it's fluxing the metal. I can even scrape the crud from the pot walls with it while fluxing, and overall, I think it's the best method I've found to date. It even SMELLS a lot better than most other stuff I've tried.

[montana_charlie]

it would not form an impediment if the metal was "gassing off", as I would assess the reaction if tin was in fact getting "burned out".
I think the term 'burned out' is the problem in this discussion.
Tin boils at about 4700 F. so that is where it would vaporize (or 'gas off').
Looking at it from that perspective, I believe you are absolutely correct in saying that tin won't burn off at casting temperatures.
That leaves the loss of tin due to skimming off oxidation as a possibility that a caster might have to consider.

On that question, you say...

I would expect a chemical analysis of oxide from a potful of bullet metal to contain just about the same proportions of the elements as the original contents of the pot contained.
That may also be absolutely true. As you (and buck1) said, an analysis of the 'scum' would answer that question.

If you are right, it would greatly simplify my life. Until those analysis results arrive, I'll just keep fluxing it back in.

Just thinking about fluxing, I recently started using wooden dowels for that job,
Regarding everything you said on this subject, I absolutely agree.
CM

[buck1]

[QUOTE=
Just thinking about fluxing, I recently started using wooden dowels for that job, thanks to waksupi's writings here at Cast Boolits. It's a great way to get carbon right down into the bottom of the melt, and the dowel makes an excellent stirrer even while it's fluxing the metal. I can even scrape the crud from the pot walls with it while fluxing, and overall, I think it's the best method I've found to date. It even SMELLS a lot better than most other stuff I've tried.[/QUOTE]


I have been meaning to try that, but I keep forgetting!
I love these discushions, they make us all think a little and cut through some of the the old wives tails.
A open mind is a powerfull thing. :) ....Buck

[BruceB]

Re: a lab analysis....

We have a metallurgical lab here at the mine, but it's primary purpose is to do assays on samples of our gold ore production. Tomorrow I'll try to get hold of one of the senior folks and just see if, by some wild chance, they could do a test for us on a lead alloy and oxide thereof.

If not, I might be able to get some pointers on having a test made elsewhere, without paying an arm and leg.

I certainly agree that a proper analysis could put a lot of conjecture to rest!

[Marlin Junky]

Since I started placing a heaping Rowell #2 ladle full of clay (AKA, Stater Bros. generic cat litter) on top the melt in my 40# Magma MasterCaster (special ordered without the bottom pouring feature) I don't worry about oxidation or fluxing. Occationally, I stir the clay through the melt and some dross floats to the top but it's pretty easy to keep it out of my dipper for the duration of a 2 to 3 hour casting session. I just push the layer out of the way to fill the dipper. When the clay gets too dusty, I replace it, usually during a new casting session startup.

BTW, once you've mastered a Rowell #2 ladle, +/- 0.1 grain with quality boolit molds is possible and I throw back all heavy weight .30's (greater than 180 grains) that are outside +/- 0.2 grains. Actually a more accurate statement would be, I throw back all boolits that are under weight by more than .3 grains because I very rarely cast boolits that are more than 0.1 grain over my expected weight for any given mold.

MJ

[montana_charlie]

Re: a lab analysis....
I (for one) certainly wish you the best of luck in having that done.

Speaking of gold...how hot does THAT have to be to cast good bullets?


Since I started placing a heaping Rowell #2 ladle full of clay (AKA, Stater Bros. generic cat litter) on top the melt...
From what I have read elsewhere, I could believe THAT is the only thing a Rowell ladle could possibly be good for...until you said,

BTW, once you've mastered a Rowell #2 ladle, +/- 0.1 grain with quality boolit molds is possible...
Now, I have finally heard someone (someone besides 'the antimony man') say that they can actually be used to cast good bullets.

I have passed up more than one...maybe I'll buy the next that I see.
CM

[buck1]

Re: a lab analysis....

We have a metallurgical lab here at the mine, but it's primary purpose is to do assays on samples of our gold ore production. Tomorrow I'll try to get hold of one of the senior folks and just see if, by some wild chance, they could do a test for us on a lead alloy and oxide thereof.

If not, I might be able to get some pointers on having a test made elsewhere, without paying an arm and leg.

I certainly agree that a proper analysis could put a lot of conjecture to rest!


There is someone here that had some "Type" alloy checked a wile back.
I cant remember who, he might read this if we keep it on the first page long enugh.
He had a girl friend or someone in that sort of business. FWIW.....Buck

[Marlin Junky]

montana_charlie,

The Antimony Man will probably tell you the #2 is too large for casting boolits and recommend the #1. That's baloney, get the #2 and patiently learn how to use it. Pouring technique is everything but once you learn how to use a big bottom pour ladle you'll never look at the RCBS Pro-Melt or its kin again.

Variables to control while using the Rowell #2 are: rate of flow, stream height and over-pour. Speaking of over-pour, the placement of clay on top of the melt actually limits two casting dilemmas (1) oxidation; and, (2) splashing on the mold surfaces while over-pouring. Just a word about stream height: Some molds like a little more pressure to fill out their bases and I let the metal fall about 3/4 of an inch or so. On other molds than tend to produce finned or whiskered bullets, I place the ladle's spout lightly on the edge of the sprue hole's countersink. There's no doubt in my mind (yes, I've actually owned an RCBS ProMelt) that casting with a #2 ladle affords far more control than is possible with the best bottom pour outfit. If I though it wasn't a waste of money to have Magma drill a hole in the bottom of my MasterCaster, I wouldn't have special ordered a ladle-only furnace from them. No speed of casting issue applies here either because the #2 ladle doesn't cool like the baby sized ladles from Lyman and RCBS (does anyone really buy the Lee ladle for actual casting?) and you can fill a big two cavity mould in about two seconds with practice. The only thing you wait for is metal solidification.

MJ

If I ever buy a 4-6 cavity mould I would also grab a Rowell #3 ladle like I should have done instead of buying the #1 ladle at the same time I bought the #2 ladle. I feel the #1 is simply too shallow for pouring 200+ grain boolits into more than one cavity, but it still holds more metal than an RCBS ladle.

[David R]

My "ladel" holds 22 lbs of alloy and has an adjustable flow rate.

RCBS Pro Melt.

Don't take me too seriously.

David

[LAH]

And mine holds 40 pounds. Works great.

And Don't take me too seriously either.

[garandsrus]

Buck,

Quote:
There is someone here that had some "Type" alloy checked a wile back.

That may have been me... I bought some Monotype and Foundry Type from a person and told others about it in the buying and selling section. After I melted mine down into ingots, I took one to a local recycler who had a hand held "gun" that could read the composition of the alloy. In just a few seconds he was able to tell me the chemical composition of the ingot.

Here's what I would propose for a test:

Add some alloy to the pot that includes a fair amount of tin, such as Linotype, Foundrytype, or Monotype. Let it melt, then flux. Run the pot pretty hot and scrape off the oxidized layer every 5 or 10 minutes. Save the ozidized layer by itself. When I have "enough" I can remelt it by itself into an ingot. I would plan to re-flux the ozidixed scrapings while casting it into an ingot. Compare this to a poured ingot from the same pot of lead. Then, ask the person to analyze both samples to see if they are the same.

Any other suggestions as to how to improve the test?

John

[montana_charlie]

a local recycler who had a hand held "gun" that could read the composition of the alloy. In just a few seconds he was able to tell me the chemical composition of the ingot.
I am constantly surprised by technological advances, but that is a device I would have to see to believe.

Are you sure that the readout wasn't telling you the 'speed' of the fast one he was pulling on you?
CM

[montana_charlie]

a local recycler who had a hand held "gun" that could read the composition of the alloy. In just a few seconds he was able to tell me the chemical composition of the ingot.
I am constantly surprised by technological advances, but that is a device I would have to see to believe.

Are you sure that the readout wasn't telling you the 'speed' of the fast one he was pulling on you?
CM

[454PB]

I went through an "environmental audit" at work some years ago. They had to identify all the lead based paint on sight. They used a "gun" that was simply pressed against the suspect surface, and it told them if there was lead based paint on that surface. That's all it identified, I too would like to know what type instrument can analyse alloy composition in that manner.

I retired 2 years ago, and one of the biggest health and safety issue problems we fought was lead based paint. When you work in a power plant, there is constant welding, painting (involving removing the old pain), and other activities going on. OSHA is really cracking down on exposure to lead in any form. Lead abatement is a very expensive procedure, and after seeing how it's done.....pretty much a joke.

We had a lead abatement contractor do paint removal on a very large section of floor, and he screwed up. Everyone on the crew had to have blood lead level testing. I figured mine would be elevated, due to my many years of casting and shooting lead boolits. Surprisingly, my level was the lowest of all those tested, and completely under the range that OSHA gets excited about.

[mroliver77]

While I do find some of the very technical information interesting most seem not to. Most it appears to me would prefer a manual to say this is how it is done and also there is a second school of thought that does it this way with acceptable results.
I do not know for certain what fluxing does. I do know that sometimes it makes the difference between junk bullets and shootable bullets. I have a large ingot of some unknown alloy that is adulterated with something that makes it hard to cast with. If I keep the heat up and flux often with sawdust(ala Glen Fryxle) and a wooden stick(dry stick!) It makes bullets acceptable for plinking. If I dont flux it every 15 min or so it leaves some bullets with a defect that is best described as looking like oxidation. When well fluxed this is kept to a minimum and acceptable accuracy results. I assume this is zinc contamination as melt tends to flow sluggishly and makes a bunch of dross. I was advised to get rid of it. There is a couple hundred lbs of it and I shot a sub 1" 90 yard group with my Scoped o3a3 with it the other day and all groups were under 1-1/2". I cannot just throw it out!
We are sure that there is a loss of alloy when casting. It does seem from linotype evidence that there is a change of tin % in well used alloy. This leads me to believe that somehow the Tin oxidises at a greater rate than lead. I believe when people stated that the tin is burnt out it was a figure of speech and not meant it was gassed off. Then again I have seen stated many times the danger of lead "fumes". I too have found the last boolits the same weight as the first out of a batch leading me to believe that if there is any loss of alloy richness it is so little that my scale does not detect the differance. I do flux regularly though. If nothing else it gets dirt and debris out. I would be interested in the results of a well run study of dross content. Since comming to cast boolits I have learned quit a bit more than the Lyman manual teaches and still newbies are recomended this as first book to buy. Jay

[garandsrus]

I am constantly surprised by technological advances, but that is a device I would have to see to believe.

Are you sure that the readout wasn't telling you the 'speed' of the fast one he was pulling on you?
CM

Charlie,

Yep! He didn't charge me anything for doing the analysis since I was buying some lead. The analyzer even displayed a chemical symbol he had to look up on his Periodic Chart, which as you may have quessed was Antimony.

He has the device so that he knows what alloy mix he is buying with his scrap. As he explained (because I asked questions), he has to "certify" that his scrap is a certail alloy. He was sorting scrap aluminum parts that all looked similar, but were two or three very different alloys. If his scrap screws up a batch at the processor he is liable for the whole batch. He said that the "gun" cost around $20K.

This isn't exactly what he used, but it is similar: http://www.spectro.com/pages/e/p010101.htm

Here's another similar item:
http://www.niton.com/XLiXLt700_excite.asp

Here's a product like what 454PB mentioned: http://www.niton.com/XLp300.asp

If you want to look at the chemicals they can analyze, here are some element symbols for materials we deal with: Pb - Lead, Zn - Zinc, Sn - Tin, Sb - Antimony

John

[mroliver77]

boy, I am glad I kept my mouth shut about the anyliser. I was skeptical but I am tired of the taste of my foot. J

[buck1]

garandsrus , That sounds like a good plan to me! I called. My recycler has no such tool, so needless to say I cant have it done.
That alloy you bought , I bought some too. I mixed it 1 part type to 7 parts WW.
That alloy flows like water!! Good stuff. I think the % you gave were real close! I thank you for posting them!!!!

BruceB and everyone else, What do you think of this test?
.......Buck

[454PB]

Now we need to figure out the richest guy on this board and nominate him to buy one of those. Then we can pass it around via UPS and analyze our stock. At $5 per use, it would only take 4,000 members to pay for itself.

[LAH]

http://www.spectro.com/pages/e/p010101.htm


AMAZING...........LAH

[montana_charlie]

Charlie,
He said that the "gun" cost around $20K.

This isn't exactly what he used, but it is similar:

Well...you've convinced me, John.

I was skeptical but I am tired of the taste of my foot.
M.R.,
'Crow' has a delicate piquance which rivals the homespun bravado of 'foot'.
CM

[doc25]

New member here so be kind. Is there some way to remove the impurities from wheel weights to make it pure lesd to cast ML projectiles?

[waksupi]

New member here so be kind. Is there some way to remove the impurities from wheel weights to make it pure lesd to cast ML projectiles?

Sorry, doc, those Ww's will always have some tin and antimony in them. About as easy to remove, as a spoon of surgur from coffee. If you want soft balls, cast and shoot them within a couple days, and the WW's will register as nearly pure lead. Any longer, and hardening will be setting in.

[buck1]

Also you ca RE soften them by putting them in a 400F oven for a hour , then turn the ove off leave them in there with the door closed untill cool . this will give you another day or two any time you want it.....Buck

[doc25]

Thanks, the soft balls thing is scaring me a bit though :).

[dragonrider]

I can't speak about alloys, I only have what I read about and attempt to duplicate, or used to. Now I use straight wheel weights water dropped. What I can talk about is sawdust for flux. I have tried many things for fluxing, home brewed and commercial, grease, crayons, wax toilet rings, beeswax, paraffin, the whole gamut of stuff. All I got from any of them was a very dirty, slimy, gunk filled pot. Shorty after I joined this forum someone, sorry I can't remember who, mentioned that he fluxed with sawdust, something I never gave a thought to or heard about. Figured it can't hurt so I tried it. Whoever mentioned it has a great big kiss coming his way if we ever meet. My pot and bullets have never been cleaner. And it seems that my pot is still getting cleaner. I will continue using and evaluating sawdust, I use oak, for all of my casting from now on.