Alloy mix's

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  • Last Post 20 August 2012
Wayne S posted this 17 August 2012

 OK we all know that “Lino” is 84/4/12 and that Lyman # 2 is 90/5/5. I save and use lino for my .225 bullets as it seams they are more consent .  This fall I'm going to smelt a very large collection of sprue's .  to form a “general” all purpose alloy for my 7 MM, 30's  & 357's . MAX. velocity  will be no more than 1800 fps  I est. this mix will come out 97/1.0/2.0  My question is, is any more tin required ??. I think the Lyman #2 is to rich in tin, and a waste, except for thoses wanting 2500  FPS.

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RicinYakima posted this 17 August 2012

A real cut with a minimum of 1% tin will work, but how do you know you have 1%? When I was employed and had access to equipment to do 0.001% it was ok, but not now. My tests showed that at 675 degrees, I loose 1% of tin every 1/2 hour from oxidation. Tin oxidizes 350% faster than antimony and 700% faster than lead. So every hour I add one oz. of tin to a 20 pound pot. It works for me. Ric

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onondaga posted this 17 August 2012

http://www.castbulletassoc.org/view_user.php?id=3610>Wayne S

Your 1% tin is ample to aid in flow and fill out.

That is a pretty soft alloy at 97:1:2. It isn't the velocity of 1800 fps that deforms an alloy when shooting it is the ballistic pressure of the load when it exceeds the strength of the alloy in psi. The selection of a powder that yields a load with 10% less than the strength of the alloy is generally close to the accuracy sweet spot. That is for plain base bullets. Gas checks will significantly extend the usable pressure range of your 97:1:2 alloy also. The Lee 2nd Edition of Modern Reloading explains the alloy strength to ballistic pressure relation very well and proves the method with testing data that I have duplicated myself.

More tin to about 2% will give you more usability in the pot. So will a good pot fluxing method and lower pot temperature. Reduction fluxing will readily return tin oxides back to tin and into your alloy so that you can maintain nearly zero loss of tin at the temperature http://www.castbulletassoc.org/view_user.php?id=50>RicinYakima states 675 Degerees.  That 675 degrees is also hot enough to do a good reduction fluxing if you know the method.

To do reduction fluxing and return the tin oxides to tin in your alloy there are some helpful hints I can offer from experience:

1) Stop skimming so often and tossing the crud away, there is a lot of tin in the crud.

2) at 675, or when the alloy is hot enough to seriously  char a rolled newspaper, add a simple flux like 2 tablespoons pine sawdust to the melt top of a 10-20 pound pot.

3) Stir vigorously and pause to allow the sawdust to catch fire. If it doesn't catch fire it is not hot enough for reduction fluxing. The fire is needed to deprive the top of the melt of oxygen. This is required for reduction fluxing. Use good gloves so you don't burn your hands with the fire needed and have an exhaust fan very close to the back of the pot top to carry the fluxing smoke/stink away from you.

4) use a large spoon for stirring that has a curve that closely matches the curve of your pot.

5) Get a circular stir going. Pause and push the crud with the outside curve of the spoon to the side of the pot and then push the crud down and under the surface of the melt. Rub and scrub the crud firmly into the pot wall. Add more sawdust if you run out of fire.

6) keep repeating step 5 several times till there is nothing left but charred flux carbon ash debris.

This will reduce the tin oxides into tin and return it to alloy.

So stop tossing the crud and try this to keep your alloy in much better shape with tin content.

Bottom pour pots will also aid in preserving tin content if you do a reduction fluxing and then cover the melt with a layer of sawdust and leave it there during your bottom pouring to cast bullets. Do not return sprues to the pot with this method. Wait till the pot is low and add the sprues with the new metal you add to the pot. This will also aid in maintaining pot temp and keep the surface tin oxide of the sprues out of your pot till you do a reduction fluxing and return it to alloy when the new potful is hot and ready to reduction flux and cover with sawdust again for bottom pouring.

Also, the 5% tin in #2 alloy does make  it rich in tin for the very same reason #2 alloy has been the first choice for casting hunting bullets for over 100 years. The 5% tin gives #2 it's malleability and allows #2 to expand double caliber on impact with game animals when delivered with 1,000 or more foot pounds energy to game animals. The 15 BHN  hardness of #2 alloy is specific. Sure, you can make a 15 BHN alloy with 1/2 of 1% tin  for flow and fill-out of bullet molds and up the antimony to get 15BHN. What you end up with by doing that is a 15 BHN alloy that shatters on impact with game at 1000 foot pounds. Antimony has very little malleability and makes bullet alloys brittle above the 5% that is in the Lyman #2 hunting alloy.

For paper punching, #2 may really be a waste. But I won't use anything else for hunting animals I plan to humanely harvest.

Gary

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Maven posted this 17 August 2012

Gary, et al, The late Ken Mollohan questioned using sawdust/wood dust as a flux in his recent FS article, “Technical Ramblings: More on Fluxes.” The part about using wood dust is on p. 218-10, paragraph 5.

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onondaga posted this 17 August 2012

Maven:

I sure would like to know Mollohan's reason for questioning the use of sawdust for a flux. I don't have access to his article. Perhaps he was concerned with breathing the fumes of pine resin. That is a valid concern for casters that are *stubborn or ignorant of reasonable ventilation to carry fluxing fumes away from the caster.

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Maven posted this 17 August 2012

Gary, Molly didn't give many reasons for avoiding saw- or wood dust, but he did write this from the article I mentioned earlier:  “I wouldn't recommend wood dust though.  Not only is it very smoky and aromatic, but I know of at least one professional caster who blames it for almost putting him out of business because he couldn't cast good bullets after trying sawdust."  (p. 218-10, para. 5)   Btw, I don't use it myself, although I am tempted to as I've got a small amount of it lying around.  Usually it's candle wax and Marvelux for smelting as I do so out of doors.

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Wayne S posted this 17 August 2012

 Gary,etal.; sorry for no reply, my 10 day old new knee isn't playing nice, so I spend most of my time in a recliner. Thank you for the help in info on fluxing and since I don't hunt, just long range <100 & 220 yd. target shooting, I think I can limit the tin to no more than 2.5/3.0%. I bought some 95/2.5/2.5 off cast boolits so when I'm able I'll try that % with a 311467 Thank you  

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onondaga posted this 17 August 2012

http://www.castbulletassoc.org/view_user.php?id=126>Maven:

Candlewax and Marvelux do work for standard fluxing to get impurities out and candle wax will flame for a brief reduction fluxing. I am not sure if Marvelux will flame or not for a reduction fluxing.

Yes, the fumes are stinky with sawdust. A professional caster not getting good bullets after sawdust fluxing is very likely completely related to technique. The method of using sawdust to reduction flux is very different from conventional fluxing to remove impurities. Sawdust fluxing without sufficient alloy temperature does spell failure and frustration. Sawdust reduction fluxing without completing the job till only carbon ash is left on the melt surface does spell failure.

Changing to sawdust reduction fluxing is just too much of a change for some casters expecting the standard method to do as well or better with just changing to sawdust. It doesn't work that way. Sawdust reduction fluxing uses a different method.

Some will also not believe the metallurgical principle of reduction fluxing to return tin oxide to tin in a bullet  alloy.  That is unfortunate. Nearly all tin and tin oxide skimmed off the melt top could be re-alloyed to your mix instead of being tossed.

Gary

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James Ball posted this 17 August 2012

I have used old coffee grounds and had good results.also have used unopened cans of coffee that were in the closet for 8-10 ys. the smell wasnt bad to me but i like coffee.i put it on top of the melt about 1/2 inch thick so the melt is well covered.Worked for me.

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CB posted this 18 August 2012

RicinYakima wrote: A real cut with a minimum of 1% tin will work, but how do you know you have 1%? When I was employed and had access to equipment to do 0.001% it was ok, but not now. My tests showed that at 675 degrees, I loose 1% of tin every 1/2 hour from oxidation. Tin oxidizes 350% faster than antimony and 700% faster than lead. So every hour I add one oz. of tin to a 20 pound pot. It works for me. Ric

Ric, I don't mean to argue but you're wrong. If you're using mathematical formulas to estimte the loss of tin you're losing in a 20 pound pot, it doesn't concern the whole pot, only the exposed surface area actually exposed to atmosphere . The exposed surface area is minute compared to the depth of a 20 pound pot.

You guys are taking this way overboard. Ononadaga is also taking this way out to left field. LEAD ALLOY is a homogeneous conpound. The oxide surface is not just tin oxide, but also lead oxide and antimony oxide ( if alloy contains antimony). A homogeneous alloy alters melting points of all elements in an alloy. Answer to Wayne's original question, just cast, if the bullets don't cast well, try adding another 1% of tin, it ain't that much wasted to a 20 pound pot.........Dan

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onondaga posted this 18 August 2012

http://www.castbulletassoc.org/view_user.php?id=7>Dan Willems:

Of course you are correct about the oxidation of each metal in the alloy. My main concern is the tin, although all of the metals oxidize at an increased rate as the temperature goes up.

Losing lead oxide is no concern to me when casting bullets. I am unsure but believe antimony oxidizes at lower rate than tin at a given temperature, correct me if I am wrong there.

I have just about given up advising casters to cast at lower temperatures and increase their casting cadence to control mold temperature. I also have failed to be convincing about  a long stream from a ladle or bottom pour spout causing oxide inclusions in bullets.

The reduction fluxing does work and will be more helpful to the casters that just have to cast at high temperatures no matter what anybody says. They can get the tin oxides back into alloy as tin by reduction fluxing.

For me, if the alloy is fluid, I can cast it no matter how low the thermometer says the alloy temperature is by controlling mold temperature with casting cadence or external heat controls. The low temperatures do limit oxidation a whole heck of a lot more than the 800 degrees plus that I read bandied about from time to time.

The OP can conserve the amount of tin he chooses to select for his alloy with reduction fluxing and will need to add less tin to keep his alloy optimized.  He can also keep more of it there at lower casting temperatures. This is just basic metallurgy and not “way out to left field".

The OP question, “is any more tin required ??” than the 1% of his expected alloy? :

One half of 1% is sufficient tin to reduce alloy surface tension and significantly aid in fill out of bullet molds. However the one half of 1% really has to be there to do that. I will admit that 1% tin in an alloy doesn't leave enough of a safety margin for me. I am comfortable with 2% tin and get good results with little bother at all when I start with 2% tin. That is the choice I made to handle the question for myself. Your results may vary differently than mine.

Gary

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onondaga posted this 18 August 2012

http://www.castbulletassoc.org/view_user.php?id=3610>Wayne S:

There is another aspect to your question that wasn't asked by you or addressed here in this post. How good of a bullet caster are you?

A relative way to answer this for yourself before you cast with a bullet alloy low in tin is to realistically look at how well you can cast with very pure lead, even laboratory grade pure lead. Wayne, if you can really cast well with pure lead, then you don't have to worry about having any tin in your alloy at all.

Note this tidbit from RotoMetals:

"For every 1% additional tin, Brinell hardness increases 0.3. For every 1% additional antimony, Brinell hardness increases 0.9. For a simple equation, Brinell  =  8.60 + ( 0.29 * Tin ) + ( 0.92 * Antimony)"

Tin does very little to harden a lead:tin:antimony alloy, it is used for flow enhancement, thus mold fill out. Tin is also used for ductility modification in bullet alloys. If you don't need that, don't worry about it. You may however have difficulty getting antimony into alloy without the presence of at least some tin in a lead bullet alloy if you were to really start from scratch making an alloy.

Gary

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Pigslayer posted this 18 August 2012

I am a layman when it comes to metallurgy. I have been casting for about fourty years. I started casting with a Lyman cast iron pot, a bernz-o-matic propane torch, a Lyman dipper & a Lyman #358156 single cavity mold. I used wheel weights only back then. I fluxed with candlewax & a discarded metal teaspoon. Result? I cast nice bullets that shot well in my S/W Mod. 28, .357 Mag. Fourty years later I have a LEE bottom pour melter, a PID controller & custom made molds. I flux with candlewax & a discarded teaspoon or a wood dowel. (I like the dowel best) I make my own Lyman #2. Lyman #2 is all I use. I cast for .45 Colt, 7.62x54R, 7MM & .270 win. They shoot well. I keep my temps between 625F & 650F. Sometimes I flux the pot again in a casting session. Some molds are different than others in controlling temperature. Sometimes after dropping fresh bullets I leave the mold open for X number of seconds before pouring the next ones . . . it's a system that works & works well. OK, so what's the trick? Temperature! Even with my metallurgical naievity I know that one must control the temperature. I most certainly agree with Gary in keeping the temps. low. It's not hard to do & it works. Whether you're using a B/P furnace or a cast iron pot with a propane torch it can be done. Each to their own but why run the pot up to 800F? .>

If someone else had of done to me what I did to myself . . . I'd have killed him. Humility is an asset. Heh - heh.

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onondaga posted this 18 August 2012

http://www.castbulletassoc.org/view_user.php?id=6171>Pigslayer:

I can tell you why some casters run at 800+ degrees.  It works for them. I really disagree with them, their methods and reasoning and question their results  that I would love to look at under magnification.

From what I have read these casters write on their method is that their 6 cavity or large block molds require a lot of heat. Their casting cadence is very slow from drop to drop and they run their pots that high to compensate for their casting cadence or to compensate for a very aggressive mold cooling  ritual they use before nearly every pour.

I wouldn't insult them by laughing in their face because they do get results they are happy with. They find their own way to maintain a thermal balance that works but sure ignores a lot of other casting/metallurgical and practical  principles. I have actually been called stupid, a know it all, and insulted for trying to explain how they might get better results. Such is life.

Thermal manipulation does work. An extreme example I can demonstrate is with pure lead. Screaming hot 900-1,000+degree pure lead can be poured from a ladle into a completely cold round ball mold and you can get a very nice casting as the heat of the metal will warm the mold and balance out what heat is missing in the mold before the lead even cools anywhere close to solidification... you get a balance by thermal manipulation.  A very slow cadence before the next pour  with very complete cooling of the mold between pours will allow a quite leisurely casting pace that was common in early America circa 1830, when casting at a hearth with only a ladle, no pot, and a simple ball mold with no sprue cutter was popular. This also worked very well for the shooter that needed one round ball for a hunting trip.

Gary

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Pigslayer posted this 18 August 2012

onondaga wrote: http://www.castbulletassoc.org/view_user.php?id=6171>Pigslayer:

I can tell you why some casters run at 800+ degrees.  It works for them. I really disagree with them, their methods and reasoning and question their results  that I would love to look at under magnification.

From what I have read these casters write on their method is that their 6 cavity or large block molds require a lot of heat. Their casting cadence is very slow from drop to drop and they run their pots that high to compensate for their casting cadence or to compensate for a very aggressive mold cooling  ritual they use before nearly every pour.

I wouldn't insult them by laughing in their face because they do get results they are happy with. They find their own way to maintain a thermal balance that works but sure ignores a lot of other casting/metallurgical and practical  principles. I have actually been called stupid, a know it all, and insulted for trying to explain how they might get better results. Such is life.

Thermal manipulation does work. An extreme example I can demonstrate is with pure lead. Screaming hot 900-1,000+degree pure lead can be poured from a ladle into a completely cold round ball mold and you can get a very nice casting as the heat of the metal will warm the mold and balance out what heat is missing in the mold before the lead even cools anywhere close to solidification... you get a balance by thermal manipulation.  A very slow cadence before the next pour  with very complete cooling of the mold between pours will allow a quite leisurely casting pace that was common in early America circa 1830, when casting at a hearth with only a ladle, no pot, and a simple ball mold with no sprue cutter was popular. This also worked very well for the shooter that needed one round ball for a hunting trip.

Gary I concur.

If someone else had of done to me what I did to myself . . . I'd have killed him. Humility is an asset. Heh - heh.

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Harp posted this 19 August 2012

I have been casting for years with out a lot of success. At best it has been with mixed results. Since paying attention to members like onondaga and others I have had better results. I also have seen the error of my ways with cleaning rods and I am switching to bore snakes. Thanks Gary.

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CB posted this 19 August 2012

Wow. What to say... I cast at 800 or so with most of my 4 cavity aluminum moulds, and often times with smaller caliber 2 cavity aluminum moulds. I cast hot in the beginning of a session with iron moulds, but usually adjust the temp down a bit when the mould hits it “sweet spot". I have a 4 cavity H&G 503 that casts poorly until the bullets start frosting, then everything goes pretty quickly from that point at 650 degrees. I contrast, I have a few Lyman 4 cavity moulds that prefer 700+. I use plenty of tin, probably too much, so that's not the issue. My bullets come out well filled, with little weight variance, so I cannot believe I'm doing anything “wrong". I simply believe that's it's necessary to tailor everything involved to the individual circumstances. I pretty much know what my individual moulds need for temp, and casting style (ladle or bottom pour), casting cadence and even alloy. Some of my moulds simply can't be used at the same time as others because their “personalities” are so different.

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Pigslayer posted this 19 August 2012

I used to run the melt hot to get the mold(s) warmed up but long ago found that If I pre-heated the mold by letting one corner of the mold sit in the melt OR heating with a Bernz-o-matic torch I was able to cast nice bullets a lot quicker. Some use a hotplate to warm the mold. I have a hotplate but adding that to an already heavily taxed 20A circuit would kick the breaker.

     Each to their own & whatever works best for you. I had the displeasure of breaking in a new .490 round ball mold yesterday. It had the usual film of oil on it. I tried to clean it with lacquer thinner prior to casting but . . . as usual it took time & heat to get it casting roundballs without wrinkles. I finally got it though and have about 100 nice roundballs for my 50 caliber flint on the bench. Wanted to go to the range this AM but . . . it chose to rain today

 

Pat

If someone else had of done to me what I did to myself . . . I'd have killed him. Humility is an asset. Heh - heh.

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onondaga posted this 19 August 2012

http://www.castbulletassoc.org/view_user.php?id=3817>Harp :

Thanks, Glad I have helped.

http://www.castbulletassoc.org/view_user.php?id=2451>anachronism & http://www.castbulletassoc.org/view_user.php?id=6171>Pigslayer:

If we get good bullets, at one time or another we have found a thermal balance with a mold and an alloy that has taught us what it likes. I have tried to steer casters toward what history and metallurgy tells us that works.

I started casting with gold at 5 years of age and bullets at 7 years of age. Dentists, Scientists, metallurgists, artists and competitive shooters elmered me from the beginning and treated me as an adult. It has been fun and continues to be fascinating and still is a learning experience at 62.

Gary

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pat i. posted this 20 August 2012

onondaga wrote: Dentists, Scientists, metallurgists, artists and competitive shooters elmered me from the beginning and treated me as an adult.Gary LOL!! Never heard the term “Elmered” used before so went and looked it up on Google. After seeing the Urban Dictionary's defintion it might be a good idea to edit your post and replace elmered with mentored. 

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onondaga posted this 20 August 2012

elmer = elderly mentor, it is a colloquial or regional term for someone considered brilliant and respected to a younger person or a novice in an area of learning.

The term is also associated with Elmer Keith, an author of many shooting articles and books. Elmer Keith was the same age as my grandfather and an acquaintance of his I was introduced to briefly at about age 5.

Consider also, the purpose of the Urban Dictionary.

Gary

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Pigslayer posted this 20 August 2012

pat i. wrote: onondaga wrote: Dentists, Scientists, metallurgists, artists and competitive shooters elmered me from the beginning and treated me as an adult.Gary LOL!! Never heard the term “Elmered” used before so went and looked it up on Google. After seeing the Urban Dictionary's defintion it might be a good idea to edit your post and replace elmered with mentored. 

Oh now! We all knew what he meant.

 

If someone else had of done to me what I did to myself . . . I'd have killed him. Humility is an asset. Heh - heh.

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Pigslayer posted this 20 August 2012

onondaga wrote:

The term is also associated with Elmer Keith, an author of many shooting articles and books. Elmer Keith was the same age as my grandfather and an acquaintance of his I was introduced to briefly at about age 5.

That's impressive!!

If someone else had of done to me what I did to myself . . . I'd have killed him. Humility is an asset. Heh - heh.

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richidaho posted this 20 August 2012

Thanks for all the info in this post. Onondaga makes me want to go back to school lol.

Rich L (richidaho)

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