fluxing technique

[triggerhappy243]

what I have is about 400 pounds of ingots that were smelted from 100 % COWW,( not properly cleaned) that I was casting into 45 acp bullets and just started casting keith style 44 mag bullets. some i see inclusions in the drive bands. it is the visual dirt i see in the ingots that I see that has me bugged. also when I dump the melt into the ingot moulds, their is either black "SOOT" looking powder or a light olive drab powdery dust that pours out when i dump the pot. I know the melt is not as clean as i would like or as clean as it should be.

My goal was to have all the ingots have the same content of tin and antimony. Now I am not so sure. this is one of the reasons I thought to remelt and blend all of it so it would be closer in content across the board.......... if that makes any sense.

Turn out? well.... the 45's are ok. I use a lee 2 cavity mould. 200 swc. and they shoot and feed good enough for me. the 44's well that is where i need help. they do not fill out as well as i would like. rounded edges of the drive bands mainly. it is a lyman 4 hole 429421. both ends do not fill out good and most always are rejects. this thing frustrates me. Not to mention how the bullet Dia. changes over time. I still am lapping out the cavities to cast a little larger dia. shooting for .432 after about 2 weeks sitting.

someone said on one of the threads that I might not have enough tin percentage in the melt. now I know what all that shiny stuff was that went into the trash. Now I think I need to replace it.... the other reason to remelt all the ingots all over again. maybe build a bigger melting pot. I can only do about 50-60 pounds at a throw.

[geargnasher]

You do realize that mentioning tin content will start a whole new fight here, don't you?

Seriously, though, it will, but it ought to be fun because relative tin content affects a lot of things ACTUALLY, but whether those things are good, bad, or neutral is mostly subjective and falls into the category of individual opinions and what works best for each of us in each individual gun or load combination. Rick and I don't even agree on how much tin is "best" for a given alloy, but we both have a pretty solid idea what it does and what works for each of us. Thing is, you won't find either of us trying ram a solid constant number down YOUR throat about what tin content you should strive to maintain in wheel weight metal. Others will. When they do, you will just have do try some things and make your own decisions, like you should be doing with everything once you have armed yourself with knowledge.

Sounds like you are having more trouble with controlling mould temperature than you are with your alloy's flow properties. Alloy temperature and mould temperature are two different things, and yet another hotly contested point between those who know what's really up and those who are in denial of basic, metallurgical facts. The recent quality and consistency of Lyman moulds, or rather the lack of both, is still another sticking point. You might be in for quite a ride if this keeps up. Whatever you do, DO NOT purchase a Swedish Mauser and attempt to shoot cast bullets in it, or if you do, don't post publicly about it. Trust me on that . Back to the topic at hand, the gunk in the pot and inclusions in your alloy and bullets is likely just oxidized metals, possibly good metals, possibly bad, but the proper use of sawdust like Brad explained with the ladling metal through it repeatedly will take care of it either way. A really slick trick for getting that powdery junk and clinging dross out of your pot is to scrape at it with a DRY paint stir stick while the empty pot is still on and up to melting temperature. Don't be surprised if little shiny droplets of clean, reduced metal start to form out of the oxidized powder and dross.

Gear

[leftiye]

This may have been said before here, but it IS simpler than all of this. Carbon will take oxygen away from lead oxide, tin oxide, and the oxides of the metals we use to make boolit alloy. Leaving (and returning to the melt) pure metals. Almost anything containing carbon will do this. Remember there are two actions we want to have happen here, reduction as just described, and true fluxing which is cleaning the metal of dirt, and etc. from the metal. Some fluxes like Marvellux will also trap the dirt and etc. (and coat your pot with borax). I use sawdust. But for some types of carp "fluxes" like buck beaver flux and some others do work much better where removing inclusion causing items from the lead. I'm sure there's more to it than this, but professional linotype fluxes appear to be micro fine graphite in a carrier of high temp oil.

[jonp]

I guess I ran sideways into something. I certainly am not smarter in this than most of the others posting on this question and have absolutely less experience gaining most of what I know on this forum and from reading but somehow I came to the conclusion that I was adding woodshavings when melting down the wheelweights to get rid of the trash and then adding paraffin to "reduce" the tin back into the melt after cleaning and keep it there as a final step after adding a little pewter back in to make up for any lost during the casting of the ingots skimming the carbon from the top. That is, keep the final melt where I want it. Adding the wax to my pot took the place of, say, Marvelux. I was not preventing the oxidation from happening in the first place by blocking the oxygen/ melt interaction just continuing to treat the results of it.

Probably wrong reasoning but apparently the right results. I have thought back to the dvd on casting that brassmagnet sent out and it seemed odd to me that sawdust/shavings were never mentioned, only wax. I took that as being because they were melting clean ingots not other "trash lead" so omitted the wood part as removing contaminants was not needed. Maybe yes, maybe no. Some of my ingots seem nice and shiney, some not so much. I've not figured out why but just chalked it up to a variable in the melt and temperature and have not noticed any difference in the pouring of boolits. I do not, however, test the different boolits based on the appearance of the ingots used to see if there is a variation in bhn which would indicate to me a difference in tin/antimony content.

Any comments on this?

[JonB_in_Glencoe]

...snip...
Now what I am P.O'ed about is all that tin and antimony I thought was trash that I skimmed off went into the trash dumpster.

...snip...
someone said on one of the threads that I might not have enough tin percentage in the melt. now I know what all that shiny stuff was that went into the trash. Now I think I need to replace it

You do realize that mentioning tin content will start a whole new fight here, don't you?
...snip...

The question I'm about to ask, has been asked before, But I think it bares mentioning again.

I'm gonna ask this question in a number of different manners, so as to best get my intent across.

Regarding the "oxide scum" that is floating on our molten COWW alloy, that we reduce with wax or sawdust...doesn't that contain a similar percentage of elemental metals of what the molten alloy contains ?

Typically COWW is about 97% Lead...So isn't the "Oxide scum" contain about 97% Lead oxide ?

I realize that the three metals in our COWW alloy, will oxidize at different rates, but are the rates so different to lower the percentage of one of them in our molten alloy, let's say "TIN" for example, when melting/casting in a normal manner at temperatures ranging from 625º to no higher than 750º, Isn't it NOT likely that we can cook out the "TIN" in our alloy ?

Lastly, to address triggerhappy243 and anyone else in a similar situation:
...OK, we are smelting a bunch of COWW's in about 20lb batches. Other than the fact that it appears that a lack of reducing and fluxing occured so as that there are some black particals in some ingots, isn't it highly unlikely that the typical 0.5% of tin content is different throughout the 20lb batches or is significantly below 0.5% because of poor reducing and fluxing ?

=====
I ask all this, as I am under the impression that it is nearly impossible to lower the content of tin in a COWW alloy, that is enough to be a detriment to boolit casting ...and I wish to be corrected if I am wrong.

[cbrick]

Trigger, Unless it's something you want to do don't re-melt 400 pounds of ingots, just flux well (and properly) as you add ingots to your casting pot.

Adding tin is not mandatory. Is it beneficial? Oh yes, very much. First, I never add anything to my WW ingots. The ingots are either well fluxed COWW poured in 5 pound ingots or well fluxed SOWW in 5 pound ingots. I use 2% Sn in most all of my handgun and rifle bullets and I add it at the casting pot by weighing the ingot and adding 2% of that weight in Sn. The reason I don't add Sn to ingots when making them is because the WW alloy is my basic metal and there is no way to know what the future might bring regarding alloy needs. If I made up all of base alloy into one alloy now you have what you have. Down the road if I want/need a different alloy for some reason I still have the base alloy that I can do with as I need at the time.

If you do add Sn the metallurgy of a Sb/Sn alloy says to not use more tin than antimony. There's been a lot of testing done on the make up of WW's from different parts of the country and the Sb percentage runs right 2% with rather surprising (to me anyway) consistency so 2% Sn is what I use. The COWW's will also run fairly consistent at 0.5% Sn. Yes that's 2.5% Sn but close enough.

When you flux your ingot's as you use them and I do even though they were well fluxed when making ingots I still use the sawdust. Lot's of folks here say to not use sawdust in the casting pot because it will cause inclusions in the bullets. Probably would if not done correctly, I've used sawdust in my casting pot for many years and I have no inclusions. I never try to force the sawdust below the surface and I NEVER use a wood stick to stir or scrape or anything else. If you use the wood stick it will char as your stirring and you have pushed that charring stick down to the bottom of the pot. The charred pieces that come off the stick will be suspended in the alloy and end up in your bullets and the bottom pour spout especially when bottom pouring. Fluxing takes time and some effort, simply stirring any kind of flux around on top of the melt will only clean the alloy at the surface. Use a spoon or a ladle to bring up metal from the bottom and pour it through the layer of carbon, keep doing this until your reasonably sure all of the alloy has gone through the carbon. Yep, time consuming and boring and worth it if you have inclusions or something in your alloy that you don't want in there.

None of it is rocket science and you certainly don't need to be a metallurgist to cast bullets but an understanding of the basics can sure make life (and bullet casting) a lot easier.

Rick

[cbrick]

Jon B, perhaps this will help answer your questions. For some time I took all of the sawdust that I had fluxed COWW with and put it into metal coffee cans, took quite awhile to fill two three pound coffee cans and they were both quite heavy so I knew there was good metal in there. I put both cans full in my smelting pot and melted out the metal from the used sawdust and got enough to make a four pound ingot. That ingot sat around for a few years until the opportunity to do the XrF testing via Tim's place of work. Samples from this ingot tested surprisingly close to the same percentages of the WW alloy it came from. This was another XrF test that made me realize that WW alloy was much more consistent than I ever thought. The metal in that 4 pound ingot had been fluxed twice with sawdust, once when it was made into ingots and again when the ingot went into the casting pot, this is where the used sawdust flux came from, not the smelting pot.

All of the results of these XrF tests where posted into a thread that was made a sticky, someone in their infinite wisdom decided that info didn't warrant a sticky and is now gone. Sad.

Rick

[Larry Gibson]

Cbrick

Mr. Fryxell is incorrect only in referring to wax as a “reductant”which it is not. Either you have lookedup the definition of a “reducer” in the dictionary as I mentioned or you haven’t.If you haven’t you argument is baseless.If you have looked up the definition and readit you understand your argument is wrong but don’t want to admit it; that isanother matter………read the definition of “flux” and of “reducer” in Webster’sdictionary (the definition hasn’t changed in 40+ years) and then read Mr.Frxell again.You will see where he wasquite correct, where he misused the term “reductant” and where you aremistaken.

Geargnasher

I suggest you also need to read the definitions of “flux”and “reducer”. And no, I’m not “smokingcrack”.Is it necessary to start with the personalattacks?You and cbrick fail to provethe point with facts so, as usual; you begin with the personal attacks andinsults.Such is perhaps better servedover on the other forum?

I’m stating facts. I’m sure the more facts I post on this the less “sense” it makes to you asyou claim.Simply read the definitionsof “flux” and “reducer”.They are factspublished in Webster’s dictionaries of which I had nothing to do with.Those are the definitions “the rest of us”use.I’m sure you can understand thosedefinitions if you’d bother reading them.I’m sure most everyone else has read them and see who is making ‘sense”and who isn’t.

Also I have notsaid you are wrong for using sawdust as a flux.In fact just the opposite; I have consistently stated that some sawdustmakes very good flux too.You continueto try to convince me sawdust is a good flux when no convincing is needed as Ido not argue that point with you.

Since you who asked mje to tell you where you arewrong; It is you, geargnasher, and acouple others who say to the rest of us that wax is not a flux and that a fluxis a reducer.That is where you arewrong and that is the crux of this argument/discussion.No one is saying sawdust is not a flux.You’re arguing with yourself.

Triggerhappy243

No need to re smelt all that alloy. Just add 2 % tin to it when you melt it tocast bullets.Let it heat up at 700 – 725*for 15 – 20 minutes and then flux it real well with whatever works foryou.I use beeswax for this.A small piece on the melted alloy and then2-3 wood matches (they light and burn instantly) then keep the smoke to aminimum.I make get some benefit fromthe wood also.Stir vigorously (but don’tsplash the molten alloy out) and the alloy will flux (the tin will mix with theantimony forming the sub metal SbSN which better goes into solution with thelead and the resulting alloy will be much better.If it is too hard for the bullets wanted youcan then cut it with lead upwards of 50% for still very good casting alloy.

Larry Gibson

[Larry Gibson]

JonB_in_Glencoe

The question I'm about to ask, has been asked before, But I think it bares mentioning again.

I'm gonna ask this question in a number of different manners, so as to best get my intent across.


You've gotten your point across very well thank you.

Regarding the "oxide scum" that is floating on our molten COWW alloy, that we reduce with wax or sawdust...doesn't that contain a similar percentage of elemental metals of what the molten alloy contains ?

You are correct; the "scum" on top is oxidized alloy of that underneath in the same percentages.

Typically COWW is about 97% Lead...So isn't the "Oxide scum" contain about 97% Lead oxide ?

You are absolutely correct.

I realize that the three metals in our COWW alloy, will oxidize at different rates, but are the rates so different to lower the percentage of one of them in our molten alloy, let's say "TIN" for example, when melting/casting in a normal manner at temperatures ranging from 625º to no higher than 750º, Isn't it NOT likely that we can cook out the "TIN" in our alloy ?

Again, absolutely correct. The tin forms with the antimony forming the sub metal SbSn which then goes into solution with the lead. Once in solution with the lead (this is what "fluxing" does) the alloys stay together. Simply melting and remelting the alloy will not separate the metals. The "oxidized" scum on top is the alloy, not just the tin.
Lastly, to address triggerhappy243 and anyone else in a similar situation:
...OK, we are smelting a bunch of COWW's in about 20lb batches. Other than the fact that it appears that a lack of reducing and fluxing occured so as that there are some black particals in some ingots, isn't it highly unlikely that the typical 0.5% of tin content is different throughout the 20lb batches or is significantly below 0.5% because of poor reducing and fluxing ?

Absolutely very "unlikely", the poor fluxing does not reduce the tin content of the COWWs. this is because the COWWs are already an alloy (from their manufacture). Thus as in the previous question/answer the tin will not separate during smelting whether fluxed poorly or not. The gray "scum" on top of the initially, once again that many refer to as "tin", to be saved is merely oxidized COWW alloy. It is not the tin separated from the lead and antimony.
=====
I ask all this, as I am under the impression that it is nearly impossible to lower the content of tin in a COWW alloy, that is enough to be a detriment to boolit casting ...and I wish to be corrected if I am wrong.

You are not wrong. The tin content of COWWs is very low. Adding 2% tin and fluxing with whatever works makes for a much better alloy.

Larry Gibson

[btroj]

Directly from Merriam-Webster dictionary-
11
a : to bring to the metallic state by removal of nonmetallic elements <reduce an ore by heat>
b : deoxidize
c : to combine with or subject to the action of hydrogen
d (1) : to change (an element or ion) from a higher to a lower oxidation state (2) : to add one or more electrons to (an atom or ion or molecule)

This is EXACTLY what we have been stating all along.

Also, please follow proper etiquette, he is Dr Fryxell when we discuss his education and professional works.

Also from Merriam-Webster we have adsorption-: the adhesion in an extremely thin layer of molecules (as of gases, solutes, or liquids) to the surfaces of solid bodies or liquids with which they are in contact. We also get from the same site this explanation-Capability of a solid substance (adsorbent) to attract to its surface molecules of a gas or solution (adsorbate) with which it is in contact.

While a wax does provide a reducing atmosphere it does NOT provide any solid residue which can act to adsorb any impurities. Sawdust does provide just such a substance.



Again I turn to Merriam-Webster as it seems to be the preferred reference source and we get activated carbon: a highly adsorbent powdered or granular carbon made usually by carbonization and chemical activation and used chiefly for purifying by adsorption. While we do produce a powdered or granular carbon we don't chemically activate it, per se, so it is not quite as effective at adsorbing impurities but it is better than nothing.

While some may prefer to get there entire chemistry knowledge from a dictionary I do not. I have absolutely no reason to disregard the professional knowledge of Dr Fryxell and his Ph D in Chemistry. I can assure you he didn't get that from a dictionary.

So yes, I think it is safe to say that one must be smoking crack in order to argue the facts of a chemical reaction with a a man who has reached the pinnacle of education in the appropriate area of study. I can think of another potential cause but will refer you Merriam-Webster to look in the N's.

[geargnasher]

JonB, the short version is I thought I used to know because some authorities said tin oxidizes out faster than other things and is lost through skimming dross without reducing, but after comparing results of my tests with several others I'm still not sure. I really doubt you're going to affect the already low tin percentage of WW much, Lyman #2, you might IF you abuse it.

the test to which Rick referred where he reconstituted the skimmings and compared to the base metal via XR has changed the way I think about the losing tin through excess oxidation. A few years before that, I did a test myself to see if it would be true to say that "overheating your alloy burns out tin". I ran a pot of WW+2%Sn at 850F for several hours, repeatedly skimming the dross. I then reduced and cast the dross into a few bullets that came in a great deal lighter (I don't remember how much exactly, something like 15% lighter) than bullets cast from the alloy from which the dross was generated. I don't know why my results were so different, except that I had added tin to the WW (during "smelting", after fluxing/cleaning) so there was a lot more tin in my mix than in Rick's reconstituted COWW smelt skimmings, and also I let my pot expose to air over and over again and just skimmed the clean oxide layer that formed over time which I'm pretty sure he didn't do when "smelting". What this tells me is that it is still probable that one can lose more tin than other metals in an overheated casting pot, but it may actually not be that way at all, and it may depend entirely on the relative tin percentage, and it may not. Whether it is or not really doesn't matter that much if you reduce and flux according to the methods Glen and the rest of us advocate, because whatever oxidizes is put right back in.

Now, regarding tin/antimony-rich metals like the type metals, was there not a commercial 'sweetener' that was supposed to be used to maintain the eutectic point of linotype alloy because it was depleted through repeated heating/cooling/skimming? Another thing, I have a box of Monotype letters and they hardness-test anywhere from 8 bhn to about 13. I bought them with the drawer and they are heavily ink-smudged from use. Still looking for a good explanation for that one.

Gear

[btroj]

Good point Gear. If tin and antimony were not depleted over time from type metal why would any business spend good money on a specific alloy to replenesh those metals in the type metal being used? I am pretty sure that the companies that made type casting machines and the metals used in them knew a fair amount about the science of the alloys. Maybe we should just consider that they knew something and we should listen?

[triggerhappy243]

Ok, so now I am getting somewhere. Now that I see the whats, wheres and the hows, I can say this. I use the same pot to cast bullets as I use to smelt. it effectively holds 50 pounds of finished melt. the pot is a 4 qt. cast iron dutch oven and the heat source is a turkey fryer burner.

The reason I thought I needed to remelt everything was solely to get more of the trash out of the lead... so when I sat down to start casting bullets, I knew I was working with the cleanest lead I had available. As things were going along, I had ingots of different levels of clean. This just confused me even more.

In a previous post, I stated that my ingots were noticeably different in appearance because of dirt and trash that i did not correctly clean out. Sorry, I am a clean and organized freak. I just wanted as clean as possible ingot stack to work with. I will put off remelting everything for a while and concentrate on one batch... see if I can clean that up nice, going the route prescribed above.... and repeat it til I see good clean metal. Then I will start over, casting for shootable bullets.

I am not looking for match grade cast bullets. I just want bullets that are consistent from melt to melt. devoid of inclusions and any thing that might be abrasive.

[btroj]

Bullets that are consistent in weight and devoid of inclusions ARE match grade.

[5Shot]

Do you guys think that crushed walnut bedding would work as well as sawdust? I have a 20 lb bag that was too coarse to use for tumbling. I tried it, and it appeared to work, leaving some grey dust to be skimmed off.

Just curious...

[geargnasher]

I've been digging through an older edition of The Metals Handbook and haven't found much specific to the Sb/Sn bond, I think it falls into the ultra-trivial category called "little-known things about little-known things". What Larry mentioned about Sb/Sn staying together even when oxidizing on the surface makes a lot of sense and explains the linotype sweetener as well as the dross analysis results, but I have a difficult time drawing an SbSn (oxide) molecule in my head. It is my understanding that SbSn is only bonded when in the alloy solution, it just has to do with how the elements link up in the soup based on the presence of other elements. That may mean that Sb and Sn oxidize at the same time, but separately on the surface. What Rick's results seem to show is that it doesn't matter the intermetallic bonds, the percentages of oxides forming on the alloy surface are virtually the same as the percentages in the alloy.

That said, I have read repeatedly that tin flash-oxidizes on the surface of the melt, and does so before either Sb or Pb does, thus forming a protective oxide coating that breaks and reforms like the crust on a lava flow. This "crust" as I'll call it, being composed mainly of tin (due to lowest oxidation point or possibly highest reactivity of the mix?) is more flexible and breaks more easily than the oxides of Sb and Pb, thus a certain tin percentage SEEMS to effectively lower the surface tension of the metal and make it flow. IDK. At this point I have reached my "Threshold of Information of Molecular Chemistry". Maybe someone can help me push it up?

Gear

[geargnasher]

Do you guys think that crushed walnut bedding would work as well as sawdust? I have a 20 lb bag that was too coarse to use for tumbling. I tried it, and it appeared to work, leaving some grey dust to be skimmed off.

Just curious...

You should do a little research about the naturally occurring toxins in walnut shells. I guarantee that walnut shell smoke will kill mosquitoes in mid-air if they catch a whiff, and some members here have reported serious illness from inhaling said smoke, though no doubt some are more sensitive to it than others. Just educate yourself and be careful. Not sure there is any advantage to using the walnut media except for possibly the convenience.

Gear

[5Shot]

Thanks...not worth risking other issues. I thought that since I had it I could use it...but I can get other material.

[geargnasher]

Here is MY personal recommendation for "The Best" flux: Sappy Yellow Pine sawdust. I hook up my compound miter saw to a clean shop-vac and powder all my yellow pine dimensional lumber scraps from time to time. Works better than anything else I've tried, including a lot of things from the pantry. YMMV.

Goodsteel, how are you doing with that reaction equation?

Gear

[btroj]

Yellow pine would be good. I should really do the same thing and just make a bunch but I have all this animal bedding left. It is aspen I believe.

The reaction equation isn't gonna come Gear, it is like the great pumpkin. It doesn't really exist.