Fluxing Lesson

[TomP]

I'm still kinda new to casting and just starting to use wheel weights for the first time.  After melting down the WW's and scooping off all the floating crud, I cast a few bullets to see how they'd fill.  Fill was good and edges were sharp but I always end up with some rough surfaces on the bullet.  This isn't frosting but like tiny pitting.  I'm guessing this is from impurities in the alloy.  I get a lot more roughness when I pour from the bottom spigot than when I ladle off the top.  I guess my question is can I get rid of the impurities down deep in the pot by just stirring the pot while fluxing or is something else needed?  I use beeswax normally.  Also, does it help to light the smoke when fluxing or just let it smoke?

BTW, I use a Lee Production Pot Four, 10 pounds capacity.

Tom P.

[dodd3]

tomp i flux every 10 minuets or so, i also use bullet lube to flux with. i have the same lee pot i have found when using wy that some times i get good bullets from one batch of ww then next time i get ones like you are getting. it' because's ww are an unknown mix you could be getting all sorts of junk in it.
i now only use sheet lead with tin mix to get my 20to1 or 30to1 mix. hope this helps.
bernie

[buck1]

Try cleaning your mold cold, with denatured alcohol. It sounds like you have some oil in the pours of the mold....Buck

I'm still kinda new to casting and just starting to use wheel weights for the first time.  After melting down the WW's and scooping off all the floating crud, I cast a few bullets to see how they'd fill.  Fill was good and edges were sharp but I always end up with some rough surfaces on the bullet.  This isn't frosting but like tiny pitting.  I'm guessing this is from impurities in the alloy.  I get a lot more roughness when I pour from the bottom spigot than when I ladle off the top.  I guess my question is can I get rid of the impurities down deep in the pot by just stirring the pot while fluxing or is something else needed?  I use beeswax normally.  Also, does it help to light the smoke when fluxing or just let it smoke?

BTW, I use a Lee Production Pot Four, 10 pounds capacity.

Tom P.

[John Traveler1]

tom p,

Casting impurities from wheelweight lead is quite normal.  Consider what those poor wheel weights have been through before they ended up in your bullet melt!  road dirt, grease, oil, tar, gravel, immbeded dirt and crap of every description!

By the way, you should always melt down wheel weights, flux thoroughly SEVERAL times, and pour them into ingots before making up your melt.  If you just melt down WW in the same pot for casting, you will certainly contaminate your bullets, molds, and ladle with CRUD that is hard to get rid of.  Pre-melting the ingots also assures you of a more uniform alloy.  I keep a few bars of 50/50 Sn/Pb solder around.  When a WW melt does not give good bullets, I bump up the tin content to help it flow better.

There is no such thing as "over fluxing".  Stir deeply and thoroughly into the bottom of the pot with your ladle.  Lighting up the smoke helps to reduce the polution and eye irritation, nothing more.  Periodically drain out your pot and scub it clean using a small wire wheel on an electric drill.  Much of your casting impurities form on the melting pot/alloy interface where the alloy reacts mildly with the steel pot.  The usual safety rules apply here:  avoid breathing the lead dust, and make sure you wash up before eating, drinking, or smoking.

HTH
John

[JPH45]

Half of what is in here is pure balderdash, the other half is strongly suspect of being wrong.

My first question would be whay are you fluxing your melt pot at all? Properly fluxed and cleaned ingots will not need further fluxing with a few proper techniques.

First, flux your ingot metal with something more robust like used moter oil. The extra high carbon content will go far in reducing the oxides we flux to be rid of. Empty and clean your melting pot, then on refilling cover the melt with either a layer of fine ground charcoal or a layer of kitty litter. You can simply allow a layer of oxidized metal to form and cover the melt. But realize that what we are doing when we flux is not to remove anything, but rather to drive off the oxygen that causes oxidized metal, recombining the metal from the oxide with the metal in the pot. We accomplish this in fluxing by providing the nessicary carbon to drive the recombining of the metal trapped by oxidation.

Too much fluxing can cause the very thing some would have us believe is the reason we flux, to rid the melt of impurities. Over fluxing can actually add trash to the melt, and that is very bad indeed.

If you are a dipper oriented caster, a Rowel ladle from www.theantimonyman.com will serve to keep you pouring clean metal as the poured metal is from the bottom of the ladle, not off the surface. Continual dipping constantly exposes new metal to the atmosphere, creating the very condition that requires fluxing, so the best solution is not expose the melt to the atmosphere.

We do this by bottom pouring and either covering the melt with a material to create an oxygen impervious barrier, or simply allow the melt to oxidize enough to create it's own barrier. Even humble sawdust can be used for this, and is in fact the material used in lead foundries.

It must also be noted that heat is one of the components of metal oxidation, and the higher we temp we cast at, the more freely the melt wants to combine with the atmosphere. Cast at the lowest temperature which keeps the molds hot enough to cast reliably. You can control frosting through the speed of your casting rythem. Typically, 650-700 degrees is enough, another reason to have a thermometer.

If you would really like to know more about casting, the myths and the realities, I would suggest a long visit at www.castboolits.gunloads.com do a few searches on this and other casting questions and find out how it is really done. I haven't fluxed my melt pot in over two years, and have no plans of resuming such foolishness. I cut out a lot of wasted energy, and spent more time casting which in itself decreased my rejects and improved the overall quality of bullets I was casting. The less I flux the better I like it and so do my boolits.

[John Traveler1]

JPH45,

I did not know that I was promoting "pure balderdash" as you put it.  I simply stated what has worked for the NRA Techical Advisor and no less an authority than the Lyman Cast Bullet Handbook, and most every maker of bullet molds and casting equipment.  We have to assume that they know a bit more about bullet casting that most of us will ever learn.

I am aware of those techniques you mentioned i.e. minimum fluxing, and using carbon-containing material to blanket the melt.  Commercial foundries have the luxury of metallurgical laboratories, die casting machines, and resources that amatuer bullet casters do not have.  They likely produce very large cast lead alloy objects, and nothing relatively small like small arms bullets.  Commercial bullet casters use centrifugal or pressure feed to fill the mold cavities.  Do THEY refuse to flux their melt pots??  Just curious.

How do you control melt uniformity without fluxing?  The lead, tin, and antimony DO separate, you know.   Remember the old-time linotype machines?  If I remember correctly, THOSE melt pots required constant fluxing and cleaning to maintain acceptable type quality.
 
I must admit to not having tried those non-fluxing techniques you mentioned.  However, in the interest of learning something new, I will check out that site link you posted.

John

[Lloyd Smale]

IVe heard both theroys on fluxing. Both doing it often and not doing it at all. Im not a scientist and dont give a dammed about all the technical mumble jumble. I use what ive found WORKS from the school of hard knocks. Ive tested many batches of bullets for uniformity and believe me you can overflux. SOme people say that tin and lead cant seperate once combined. I dont know if its true or not but id have to say from experience that if it does its in such small quanities as to not matter. Fluxing will clean your pot and alloy some say it wont but it does and i believe thats about all it does. I flux the snot out of my ww when smelting them and make good clean ingots. When i cast i fill the pot with clean ingots melt it flux it once (and dont even know why) and wont flux again and thats even if i add lead. I use a bottom pour (actually 3 of them) and have never had the lack of fluxing effect bullet quality in any way. That includes visual and actually weighting bullets. Ive ran into more problems with test batches that i have fluxed every 15 minutes with inconsistant bullet weights then i have with batches i dont flux at all. Granted if you ladle cast you about have no choise. But im no rookie you can ask anyone who knows me how many bullets ive casted in my life and i gurantee you youd shake your head at it. You can either believe me or belive what some so called expert says or some scientist or do what i did cast a couple million bullets and find out for yourself.

[JPH45]

JPH45,

I did not know that I was promoting "pure balderdash" as you put it.  I simply stated what has worked for the NRA Techical Advisor and no less an authority than the Lyman Cast Bullet Handbook, and most every maker of bullet molds and casting equipment.  We have to assume that they know a bit more about bullet casting that most of us will ever learn.
John

Sorry, didn't mean to leave anyone feeling blasted....My bad, not too good with words sometimes. I almost typed "sounds like it was read from a Lyman manual", perhaps it is good thing I didn't.

To assume that that just because someone is selling something, that makes them an expert is bad thinking at best. Fact of the matter is that Lyman refers folks to the listed site, so I think the folks there may know more than the average bunch of folks on a website.

As to metals seperation, lead and tin form a true solution, this means that whatever amount the lead will take (22% or so by weight) makes a molecular bond with the lead, that is waht makes it a true alloy, kind of like what happens when you add tin to copper....you get brass, a completely different alloy form the base metals. This bond can only be broken with heat and the presence of oxygen. Tin will oxidize out of the melt, but not at any rate that will alter the alloy significantly. You can't get those kinds of temperature in your melting pot.

Antimony is a different animal altogether. Antimony does not alloy with lead, it will with tin. In a picture of the molecular structure of a lead/antimony mix, the antimony forms long tendrils that encapsulate the lead molecules. This is why it takes two weeks for WW to reach its mature hardness, the antimony is still growing. It is also why we are able to heat treat antimony alloys in the presence of arsenic. Arsenic alone will harden lead, but in combination with antimony, through rapid cooling (such as dropping the just cast bullet in water) we are able to freeze the antimony in a molecular relationship with the lead that allows for harder bullets. But arsenic must be present in the alloy to heat treat, otherwise all you get is cold bullets.

So, lead and tin do not seperate, tin and antimony do not seperate. Lead and antimony do not alloy in the true sense. We do not flux to keep the metals in solution. If that were true then as soon as the metal were removed from the heat and flux source, they would seperate.....we couldn't make bullets, or any other alloys for that matter.

A conversation about lead/tin/antimony alloys with Bill Ferguson of www.theantimonyman.com will go far in helping to see how these alloys really work together.

Lyman states plainly that the mechanism that makes fluxing work is unknown, that is flatly false. Fluxing works by providing a carbon rich environmet that "steals" the oxidized metal back from the oxygen. The metal prefers the carbon over oxygen in other words.

Over the years lots of misinformation and wives tales has been propogated in the firearms industry and press, especially about cast bullets, Lyman and the NRA amoung the offenders. It is why conversations like this take place. Simple obsevation of the melt will reveal the formation of oxides. That does not mean that an untrained metalurgist will draw the right conclusions about what is being seen. And if the right conclusions aren't drawn.......And so here we are today, still working with bad information that is at least 100 years old, probably more so.

It was my intent to call into question the information presented, it is at best incomplete. It was not my intent to leave anyone feeling belittled or run roughshod over. My apologies.

..........Somewhere in this I would like to add that the tin oxidizes first because it is lighter.....on the periodical chart. Similar to why we galvanize steel, it will sacrifice first. It is a result of things at the atomic level. If we don't realize that what is occuring in the melt is really happening at the atomic level, then what we see there will always be a mystery to us.

Also, join the Cast Bullet Association

(Edited for spelling and link repair and added CBA)

[JPH45]

Link to  another disscussion on the topic....

http://www.forum.handloads.com/forum_post.asp?TID=7895&PN=1

Edit:

Apparently the link won't work. go to www.handloads.com and click on the cast bullet forum. Good disscussion there on this topic with a good link to an exellent article on the subject as well. The article speaks of using fluxes like "Marvelux" which is basically borax. Works good but is hydroscopic. It will draw moisture when cold and has the effect of adding bits of water to the melt

[John Traveler1]

JPH45,

Many thanks for your tactful and informative reply.  No need for you to apologize at all.  I must admit to some initial grumpiness when I read your statements, as I thought I understood alloy mixtures with a minor in physical chemistry and engineering materials courses.  I've also dabbled in metallurgy in relation to my work.  These forums are wonderful in providing the medium for comparing and sharing ideas (even wildly different ones) and learning new things.

I truly am amazed that you get good/better quality bullets without fluxing.  Do you do competitive BPCR shooting?  I know that sport requires the very best in casting techniques.  After reading your learned and knowledgeable explanation of alloy mixtures, your "no flux" position makes a LOT of sense.  I'm still browsing the cast boolit site to acquire more info.  Thanks again for providing the links.

John

[Lloyd Smale]

thanks for the facts. They backup totaly what my experience has been in the real world.

JPH45,

I did not know that I was promoting "pure balderdash" as you put it.  I simply stated what has worked for the NRA Techical Advisor and no less an authority than the Lyman Cast Bullet Handbook, and most every maker of bullet molds and casting equipment.  We have to assume that they know a bit more about bullet casting that most of us will ever learn.
John

Sorry, didn't mean to leave anyone feeling blasted....My bad, not too good with words sometimes. I almost typed "sounds like it was read from a Lyman manual", perhaps it is good thing I didn't.

To assume that that just because someone is selling something, that makes them an expert is bad thinking at best. Fact of the matter is that Lyman refers folks to the listed site, so I think the folks there may know more than the average bunch of folks on a website.

As to metals seperation, lead and tin form a true solution, this means that whatever amount the lead will take (22% or so by weight) makes a molecular bond with the lead, that is waht makes it a true alloy, kind of like what happens when you add tin to copper....you get brass, a completely different alloy form the base metals. This bond can only be broken with heat and the presence of oxygen. Tin will oxidize out of the melt, but not at any rate that will alter the alloy significantly. You can't get those kinds of temperature in your melting pot.

Antimony is a different animal altogether. Antimony does not alloy with lead, it will with tin. In a picture of the molecular structure of a lead/antimony mix, the antimony forms long tendrils that encapsulate the lead molecules. This is why it takes two weeks for WW to reach its mature hardness, the antimony is still growing. It is also why we are able to heat treat antimony alloys in the presence of arsenic. Arsenic alone will harden lead, but in combination with antimony, through rapid cooling (such as dropping the just cast bullet in water) we are able to freeze the antimony in a molecular relationship with the lead that allows for harder bullets. But arsenic must be present in the alloy to heat treat, otherwise all you get is cold bullets.

So, lead and tin do not seperate, tin and antimony do not seperate. Lead and antimony do not alloy in the true sense. We do not flux to keep the metals in solution. If that were true then as soon as the metal were removed from the heat and flux source, they would seperate.....we couldn't make bullets, or any other alloys for that matter.

A conversation about lead/tin/antimony alloys with Bill Ferguson of www.theantimonyman.com will go far in helping to see how these alloys really work together.

Lyman states plainly that the mechanism that makes fluxing work is unknown, that is flatly false. Fluxing works by providing a carbon rich environmet that "steals" the oxidized metal back from the oxygen. The metal prefers the carbon over oxygen in other words.

Over the years lots of misinformation and wives tales has been propogated in the firearms industry and press, especially about cast bullets, Lyman and the NRA amoung the offenders. It is why conversations like this take place. Simple obsevation of the melt will reveal the formation of oxides. That does not mean that an untrained metalurgist will draw the right conclusions about what is being seen. And if the right conclusions aren't drawn.......And so here we are today, still working with bad information that is at least 100 years old, probably more so.

It was my intent to call into question the information presented, it is at best incomplete. It was not my intent to leave anyone feeling belittled or run roughshod over. My apologies.

..........Somewhere in this I would like to add that the tin oxidizes first because it is lighter.....on the periodical chart. Similar to why we galvanize steel, it will sacrifice first. It is a result of things at the atomic level. If we don't realize that what is occuring in the melt is really happening at the atomic level, then what we see there will always be a mystery to us.

Also, join the Cast Bullet Association

(Edited for spelling and link repair and added CBA)

[warf73]

Lots of great info.


Warf

[TomP]

Well, I step away from my computer for a couple days and what happens?  I end up getting all kinds of good advice.  Thanks guys.

After looking through all the responses to my questions I decided to remelt all my wheel weight ingots in a separate melting pot and flux and reflux with beeswax several times.  I also thoroughly scrubbed out my casting pot and removed some old scale and a bit of rust.  Whatever was contaminating my melt hopefully has been "reduced" and gone back into solution if it was some oxide of tin lead or antimony.  If it was something else, I hope it will float to the surface so I can scoop it off.

In the next day or so I'll try casting some bullets and see if the effort paid off.

Tom P.

[Chief]

I was reading a little about motor oil today and had recalled reading something about using old motor oil as a flux for casting.  I've not used it for this application so I can't say how it works but....here's a thought.  According to google, some motor oil manufacturers put a little zinc in their motor oil for it's lubrication qualities.  Just thought this was something worth sharing as even a small amount of zinc in a melt is reported to ruin its casting qualities.

Thanks
Chief

[Forest T]

Tom P I use bees wax I flux every 10 or 20 minutes whin I am casting I use a old table spoon to get the junk off the top of my melt so then I made a tool out of a hack saw blade I got the end 2 inches of the blade red hot and bent a 90 degrees in it so I can scrape the bottom of the pot with the tool and scrape the sides with the saw edge of the blade I hope this helps   Forest T

[Kenneth L. Walters]

Decades ago I wondered if a bottom draining furnace was better than a dipper when it came to casting bullets.  So with a variety of moulds I tried both.  In every case the bottom draining furnace produced more bullets and yielded a higher percentage of visually acceptable bullets.  I haven't used a laddle since.  Don't believe me.  Do the studies yourself.  Doesn't really take all that long.

I also wondered what effect fluxing had.  So I got several single cavity moulds that yielded bullets of very consistent weight and I cast with them fluxing every so often.  I saved the bullets in their as cast order noting where each fluxing occurred.  In every case, visual rejects occurred right after the fluxing and weight inconsistencies showed up.  Don't believe me.  Do the studies yourself.

Since I mostly use linotype I don't really need to flux.  When I cast with wheelweights I'll skip the crude off once in a great while but not often.  Personally I like bottom draining furnaces (I owned three RCBS's) and I don't flux.

[Dana C]

Wow, I don't have anything to add but I sure learned a lot from this tread!
You all have shined the light of some of my crappy bullets.  
Thanks all!
Dana

[454PB]

In defense of using Marvelux, those of us that use it have to adapt to the fact that it is hydroscopic. This is easily addressed by pre-warming the stirring tool. If it is plunged cold into a molten pot, it will let you know. Not necessarily an explosion, but a lot of bubbling and hissing. It has the added benefit of forming a thermal layer to help isolate the melt from oxygen.

Those of us that cast in conditions where good ventilation is not possible love the stuff. Would I use it for bulk melting ingots? No, but it is great for fluxing before boolit casting. I flux once, just before the first boolit, then no more until the pot is refilled.

[Kenneth L. Walters]

Don't think that I've fluxed an alloy, except to originally remove dirt from wheelweights, in decades.

It is comparatively easy, though time consuming, to understand what fluxing does or does not do.  Pick a single cavity mould, cast saving your bullets in their as cast order.  Note where you flux.  Visually inspect and weigh all the bullets.  Plot weights noting which bullets were visually acceptable and which were not.

The plot will show a drop in weight right after the fluxing.  Visual rejects right after fluxing will also rise.  Undoubtedly the fluxing caused heat loss in the mould because the casting sequence was disturb and that heat loss caused these two effects.

Repeat the experiment exactly as before but with no fluxing.  Chances are you visual acceptance rate will go up a bit and the weight plot will be a bit more uniform.

Repeat a third time adding alloy and keeping track of where that was done.  Here what you'll probably find is no impact.  If you run the furnace temperature up just before adding more alloy then the cold alloy will not cool down the furnace much and thus no ill effects will occur.

Fluxing does not have to be the stuff of myth.  Experiments like these will absolutely show what effect fluxing does or does not have.

Fluxing before or after a casting session to get crude out of wheelweights is worth doing the first time you use a dirty batch of wheelweights.  Fluxing for any other reason has no merit.  Do not take my word for it.  Run these experiments and see for yourself.

My guess is that the "tiny pitting" is grain structure.  That has a lot to do with the temperature of the alloy and how fast the alloy hardened in the mould.  Dennis Marshall wrote about that in Lyman's 3rd edition Cast Bullet Handbook.

[Steve P]

I cannot go into the technicalities of lead, antimony, and tin.  I cannot recite molecular properties or go into chemical make-up of lead in a pot.  I can tell you what works for me and my buddy.  He has been casting bullets for nearly 30 years.  The bullets are just plain accurate.

We melt wheel weights in a large cast pot.  We use only the wheel weights that have the clip on them.  The soft wheel weights that have the double sided sticky tape are of a different composition and will mess up your mixture.  I don't know why, but they do.

When the weights are melted, most of the dirt, clips, junk, float to the top.  We have a ladle made that will scrape up the clips, and allow the lead to flow back into the mixture.  Turn it around and you can scrape off the dirt.  I few stirs of the mixture will bring more dirt to the top for scraping.  Then we drop and piece of parafin, an old candle, left over bullet lube, or similar wax base substance and light it with a match.  Sometimes it is hot enough to light the match by itself.  We let it burn until it goes out, then scrape off the smokey dirt and residue.  

Next we start casting ingots.  These are ladled out of the top of the pot and into clean molds.  RCBS molds and a couple of old cast muffin pans.  If the mixture starts to look dirty on top, or dirt starts to float up, we flux again.  When we start getting toward the bottom of the pot, we add more wheel weights and start over.  We never use the last inch or so of mixture in the pot as it usually has dirt in it that does not raise to the top.  

The ingots are the only thing that ever go into the Lee Casting Pot.  We flux the pot when the pot is full of molten mixture and run out half dozen bullets or so to clean the bottom of the pot and warm the mold.  These bullets are thrown into weight bucket to be remelted.  

Once the mold is to temperature, we cast bullets and drop from mold into 5 gallon bucket with about 2 gallons of water in it.  We may cast 500-1000 bullets in one setting or over a period of a couple days.  After cooling and drying, the bullets are sorted and weighed.  All bullets within 1 grain are gas checked if needed, sized, lubed, and stacked neatly for loading.  

With heavy bullets like 200 grain 357, you may have a set of 2-300 that weigh 208.0 - 208.9, 2-300 that weigh 209.0 - 209.9, and a few 205s, 206s, 211s etc.   We take 100 of the 208s and load them.  

Most of our bullets cast in this manner shoot minute of angle or less thru our Contenders and XP100s.

Hope this helps someone out.

Steve  

[bob allen]

As for casting in an envrionment with poor ventilation,this is not a good thing to do.I cast for years with what I thought was a pretty good set up.
It was found that my heavy metal content was very high.Antimony was right off the map to say nothing of arsnic ,lead,mercury,and a host of others.Chelating gets it out but it's best to avoid  needing it....

[454PB]

JPH45,



 It is also why we are able to heat treat antimony alloys in the presence of arsenic. Arsenic alone will harden lead, but in combination with antimony, through rapid cooling (such as dropping the just cast bullet in water) we are able to freeze the antimony in a molecular relationship with the lead that allows for harder bullets. But arsenic must be present in the alloy to heat treat, otherwise all you get is cold bullets.

The subject of heat treating came up recently on the castboolits forum. A poster asked if linotype and pure lead would heat treat. I responded that I didn't think it would........no arsenic.

As the discussion progressed, I decided to give it a try. I used 75% pure lead and 25% linotype and water quenched them, then began hardness testing. The boolits tested 11 BHN air cooled, and 14.2 BHN quenched immediately after casting. A few days latter, they were up to 18 BHN. I will continue testing them at 5 days intervals.

This proved to me that a lot of the accepted theories about casting and heat treating are not true.

[blhof]

Thanks guys, I learned a lot.  Been casting for 40 years, learned by trial and error.  Have found that the methods stated worked for me.  I also can speak of casting at too high of a temp, even in a well ventilated area.  My neighbor several years ago was casting sinkers on a grand scale for sale at flea markets.  Using ww's he got free.  He was using a gumbo pot and fry cooker out doors.  He set up several molds and with a large ladle dipped up a lot of lead.  The heat got high enough to actually boil the lead in the pot.  I warned him to control his heat.  He passed out at work and subsequent blood tests showed heavy metal contamination.  He went through chealation therapy and was ok.  He still casts but with more careful temp control and thorough washing and clothes change before eating. Lead is TOXIC and should be treated as such.  A few basic precautions can save you from a very expensive procedure.  My friend was lucky, he was active duty and the USAF paid his high med bills.  I warned him not to tell them of the scale he was casting.  There is a point that the govt can rule you libel for your own medical in the event of stupidity.