Why you should INSIST on an x-ray shoot of the lead you buy

[bangerjim]

Was at a yard the other day and found a bunch of probably 70-80# of really cool big HARD printing blocks, not strips. These are new advertising and the such.

Methinks to myself .... "AH-HA self, nice clutch of linotype alloy". VERY HARD STUFF! Insisted on an x-ray shoot.

OMG! 20% Sb
6% Sn
58% Pb

So far....excellent for HARD. Then the last line on the gun popped up:
16% Zn

I would have bought this stuff thinking it smells, feels, tastes, and looks like lino, when it was "contaminated" (for our needs) with 16% Zn. Probably made and excellent printing media. Not worth the time or $$.

A little Zn in your mix is no big deal. That much is something I want to avoid.

Buyer beware..............insist on your yard doing a shoot B4 shelling out your hard-earned $$.

So I walked away.................with of 90# old Pb came and 7# of new pewter plates! A buck a pound!

bangerjim

[Mitch]

Dern good thing you had a gun there to check it.problem here is there is no gun at the scrap yard that does sell lead.so I am just abit more picky on what I buy.I never buy home brew ingots or anything else that I don't know what it is.I have dome well so far doing things this way.Iguess there is good and bad in living in small town USA but mostly good.

great score on the old PB likely pure I would guess and the pewter you sole lol.

just wondering how much zn have you found to be tolerable in your lead mix

sounds like a good day at the scrap yard

Bob

[bangerjim]

I have played with Zn in alloys from 1 to 5%. No higher. At the 4-5% levels, you just need to add some more Sn for good fill-out. And for those that are paranoid about boolit weights, they will be lighter by a tad. I do not worry about weights. Whatever the mold drops, that is what I shoot!

Most load data is based on the olde school Lyman #2 alloy. I NEVER use that, so my weights will be different than what the books all show. No big whoop!

People seem to get lost in the weeds worrying about "OMG...one zinc WW ruined my whole 100# batch of melt!" Send it to me! Just sort the best you can and do not worry about a little Zn.

If I was reeeeeeeeelly desperate for a lino-type alloy, I probably would have bought that stuff. But I have many hundreds of pounds of lino already.

Everyday is a good day at the several scrap yards around me! I do not ever mess with COWW's or range lead any more. Too much other really good stuff to be had. There are definite advantages to living in a big city! Done the small town thing.....born there, been there, done that. Don't miss it at all. An x-ray shoot is really nice when using the alloy calc on here, but you can always get by with a hardness tester or artist pencils in a pinch to use Bhn as a guestimate of content.

banger

[gpidaho]

I agree with Banger on ZN. A LITTLE bit is no big whoop. I've cast a few boolits that I know contain some zinc. I just use a forgiving mould like a 230gr. RN 45 or such and cast away. GP

[bubbacrabb]

I'm glad I seem this. I bought some that was .01% zn.... so less than 1/100 of a % was zn. I'm new to the game. I've casted some boolits, lots of sinkers so I'm just learning. Thanks for another education. So little % of zn is not worth worries? Like less than 4%. I was stressed today. Probably because a zinc wheel weight touched it it came up that low, lol

[Budzilla 19]

The alloy I use has 2.7% Zn so it's not a big deal in my opinion only. When I have some crazy alloy I don't know about,I try to have it XRF tested and then rely on this alloy calculator as close as possible. Just my .02 cents. Good shooting to all.

[gpidaho]

Welcome along bubbacrabb! If ya can't be led astray by your friends, then Who's gonna do it! lol GP

[bubbacrabb]

I have a post about scrap yard lead. I was nervous buying. Struck out at all the local tire places. I did good today though I think. Found 80 some 1 lbs ingots. Some caster must of gave it up, or someone inherited it. Some ingots were 100% tin written on them also, so I feel the man knew what he was doing. I had them gunned, same as wheel weights, but with that .01 zn. Which I think isn't a big deal now. Looks like the ingots I made. This is a fun hobby. Trying to stock up a bit.

[bangerjim]

I'm glad I seem this. I bought some that was .01% zn.... so less than 1/100 of a % was zn. I'm new to the game. I've casted some boolits, lots of sinkers so I'm just learning. Thanks for another education. So little % of zn is not worth worries? Like less than 4%. I was stressed today. Probably because a zinc wheel weight touched it it came up that low, lol

An x-ray analysis is not the "end-all be-all". They are "relatively" accurate most of the time. They are the best we can do. But they can vary. I like to know approx what I am mixing, so I always get the % from the yard's gun. Is it dead laboratory accurate? Heck no! But we are not doing rocket science here! We are making little lead things hit other things far away. Knowing within a few % is more than sufficient for most if not all of us.

The % content and a good hardness tester go a long way in helping you cast repeatable alloys.

banger

[tiger762]

What I do is cast a cylindrical core of 0.365" diameter (adjustable core mold)
Then run it up into a 45cal core swage die (0.418")
Now it has had the air compressed out of it and is as close to a perfect solid cylinder as possible
For one recent measurement, I measure the diameter, 0.4185"
I measure the length, 1.286"
The weight was 496.6 grains
The volume is 2.9035 cm3
I calculate the density as 11.09 g/cm3

Now I set up a simple spreadsheet with 95% (to start) in A1
In B1, I have the equation "=1-A1" (it will then show 5%)
In A2, I put the density of pure lead, 11.3
In B2, I put the approximate density of everything else, 7.0
In A3, put the equation for the partial mass of lead "=A1*A2"
In B3, put the equation for the partial mass of alloys "=B1*B2"
In C3, add the two partial masses to get the overall alloy density, "=A3+B3"

Given the 95% initial estimate, I get a calculated density of 11.085. Recall, the density from micrometer measurements yielded 11.09. So I conclude this range scrap mystery metal is 95% lead and 5% "other stuff with approximately a density of 7".

Tin's density is 7.4
Antimony's density is 6.7
Arsenic's density is 5.7

The alloy components are likely tin and antimony, which is why I assume a density of 7 for the impurities. Hope this helps!



The alloy I use has 2.7% Zn so it's not a big deal in my opinion only. When I have some crazy alloy I don't know about,I try to have it XRF tested and then rely on this alloy calculator as close as possible. Just my .02 cents. Good shooting to all.

[coyotewacker]

Please excuse my lack of knowledge of metallurgy, what would be the problem with Zinc in casting metal ?

[tiger762]

The problem is waaay overblown. Lead has a very low appetite for alloying with zinc. It would make the melting point higher and it increases the surface tension. Tin reduces surface tension and fills molds out better. If I were casting something that requires fine detail I would religiously avoid zinc but for bullets? I skim off the grey oatmeal that floats to the top and if a few percent gets "stuck" with the lead, I'll get over it..


Please excuse my lack of knowledge of metallurgy, what would be the problem with Zinc in casting metal ?

[bangerjim]

Please excuse my lack of knowledge of metallurgy, what would be the problem with Zinc in casting metal ?


If you read all the many things about lead casting, historically (or hysterically) those "in the know" always bemoaned a Zn wheel weight or two totally contaminating their melt. Well, we know better today.

Running some Zn does not ruin your castings. As said, Sn will improve the surface tension for better fill. A few % Zn will lower your boolit weight ever so slightly (a REAL "sleep-looser" for those that weigh every single blessed boolit!). You CAN waste a ton of time stripping Zn (and Sn and Sb) out of your pot by using copper sulfate or sulfur. Not worth the time, smell, and mess.

I know some of my alloys have a "kiss" of Zn. Do I worry......heck no!

banger

[RogerDat]

Please excuse my lack of knowledge of metallurgy, what would be the problem with Zinc in casting metal ?

Too much zinc will cause the melt to turn into oatmeal. Zinc has a higher melting temperature than lead and there is a greater difference between zinc melting temp. and the lead alloys with tin. Lead/tin has a lower melt temperature than plain lead. This means you can't cast at the temperature you might consider "normal" with a given mold.

Wheel weights used to be almost all made of lead, now they are also made of zinc, in some areas a 5 gallon bucket of WW's will be 1/3 or more zinc. If you did not pull those zinc WW's out so they are not part of your melted lead you would lose the whole batch.

People either sort WW's before melting, or keep the temperature down (below 800 F) where lead melts but zinc doesn't melt so they can skim the zinc WW's off of the molten lead along with the steel clips.

Is a little bit of zinc going to wreck the whole batch, no. Is zinc something most would try pretty hard to avoid, yes. The impact also depends on the size of your melt. Banger doing 100# or more pot at once can have a couple of lbs. of zinc without having too high a percentage. Someone using a small pot on a hot plate or burner could get too much zinc from just a couple or three missed zinc WW's.

Tin helps the lead flow and cast nice sharp lube grooves and edges at a lower temp, this is "good fill out". Zinc does the opposite making it harder to cast nice sharp edges unless one gets the temps up higher, higher temps tend to cause the melt to oxidize more (gray floating dross) and some good things such as tin and antimony to cook out of the alloy. Bottom line, avoid zinc as much as possible, don't freak if a little gets in.

Zinc can be mistaken for lead, and will seem like a really good hard lead alloy, this has lead to some disasters. Big and small. I hauled about 40# of zinc ingots around for 15 years thinking they were lead. Some folks have messed up pretty big pots of lead.

[bangerjim]

Roger..........Roger!

Good points.

coyotewacker - you can easily test for Zn weights by:
1) reading them - most ARE marked
2) using side cutters - you won't be able to cut/score them like lead
3) a drop of muriatic acid - Zn foams up rapidly, lead & tin do nothing
4) sound - tap them against a 1" or larger steel bar. Lead is dead. Zinc will have a distinct ring to it.
5) melt temp - Zn will float........if you can trust your re-melting pot temp! I consider this a very poor way to sort weights.

Very easy to sort - - -just can be rather (extremely) time-consuming. That is why I quit the WW dance 2 years ago.....way too many zinkers and Fe in the buckets. Even when free, it was not worth my time and effort when I can buy good clean lead and alloys for 75¢ to a buck a pound locally.

banger

[runfiverun]

I just scrape the unknown ones on the cement.
after doing a side by side of a known zinc and a known lead ww you'll never mistake one for the other.
it has saved me from carrying wild zinc ww's home many, many times.
if one or two gets through into the smelting pot [shrug] it ain't the end of the world.

[RogerDat]

I put a few handfuls from the bucket of WW's into a box lid tray sitting in my lap. Then nip each one I throw in the "keeper" bucket with diagonal cutting pliers (dikes). If the tip of the dikes can nip a groove in the wheel weight it is lead. After doing it awhile I can spot the Fe (iron) or Zn (zinc) about 95% of the time and just toss them into sorted containers for sale to scrap yard without bothering to nip with the dikes.

Sometimes I sit doing this sorting and pondering great thoughts, sometimes I do it watching TV or a movie, other times I just sits and does it with brain totally disengaged :-)

So far have only seen one zinc WW show up in a smelting pot after sorting. Any others I might have missed don't seem to have hurt anything, but I do fairly large batches always better than 50# at a time. In my sources I typically only get about a coffee can of zinc, and less than that of steel out of a 5 gallon bucket. The ratio of lead to junk really depends on the part of the country, area in the state and even tire shop clientele. One shop only a few miles from where I get "good" buckets tends to run 50% zinc and steel. If everyplace around has that ratio you do what bangerjim has done, find another source.

runfiver you do know that with intense professional help you might not feel compelled to bring home wild wheel weights you find on the ground in the first place. Ok you would still "feel" compelled but might be able to control the urge.... maybe. Or not.