Following are some observations I have made over the last 50 years melting and blending about 50 tons of boolit base metals (Lead (Pb), Antimony, (Sb) and Tin, (Sn), Copper (Cu)) for bullet casting.
In the beginning, 1970’s, when just getting into the hobby, everything was pretty much a guess regarding the elements contained in the many pieces of “Lead” I collected. Over the years, the vast majority of source metals I collected, melted and blended have been Wheel Weights (COWWs, Soft WW’s). A fair amount of type metals (Linotype, Stereotype, Monotype and Foundry type), Tin / Lead solders, radiation shielding, shot, miscellaneous soft metals such as roof ventilation boots, plumbers lead, shower pans and pewter were also collected, melted and used.
In the beginning I had only literature and an occasional laboratory assay to help guide me regarding the composition of my metals. As a result of this my alloys were frequently less than optimal for my desired cast boolits. Later, (within the last 10 years) I have benefited from X-ray fluorescence technology XRF.
WHEEL WEIGHTS:
• I estimate that I have gathered, sorted and melted in excess of 50 tons of wheel weight material over 50 years, maybe more.
RUN OF TIRE SHOP MATERIAL (ROTS)
• ROTS is everything gathered from the tire shop, COWWs, Soft WWs, Zinc WWs, Trash, etc.
• I normally, dump the “ROTS” material on my paved driveway and rinse off all the dirt, tobacco spit, etc before starting to sort. I sort the weights into four categories COWW (Pb, Sb alloy), Soft WW (Nearly pure Pb), Zinc (Zn) WWs and Iron / Steel, (Fe) WWs.
Run of tire shop yield (ROTS):
My last 5 tons of this material has yielded:
• COWW Clean Ingot Metal = about 55 % of the ROTS weight
• Soft WWs Clean Ingot Metal = about 5 % of ROTS weight
• Zinc WWs about 10 % of ROTS weight
• Iron WWs about 25 % of ROTS weight
• Trash about 5 % of ROTS weight
• In general, I get 50% to 60 % of the ROTS material's weight in clean usable metal ingots (COWW & Soft WW metals)
• It is interesting to note that the % of COWW & Soft WW metal has been declining about 2.5% / year over the last 5 Yrs.
METAL YIELD (WEIGHT) FROM SORTED WWS:
• COWWs yield about 85 % clean alloy in ingot form (15 % Steel clips).
• Soft WWs yield about 95 - 98% clean alloy in ingot form.
WHEEL WEIGHT METAL XRF RESULTS:
• I have sampled several tons of COWWs and Soft (Glue On) WW metal over the past decade.
• The average XRF Analysis has shown the following:
o COWW = Pb +96%, Sb 3.0 % to 3.2 %, Sn 0.0 % to .2%
o Soft Glue on WW = Pb 99+ %, sometime a little Sb normally < .02% Sb
ZINC (Zn) WHEEL WEIGHTS:
• While I am diligent in my sorting process to remove as many Zinc WWs as I can identify, some always get through into the melt. While I do not have accurate temperature control in my melting process (wood fire, large metal pot) I have never had my COWW ingot metal contaminated with enough Zinc to ruin its quality only trace of Zn identified in XRF on occasion. I do find an occasional Zinc WW in the clips skimmed from the top of the molten COWW alloy, however, these infrequently show any sign of melting. I believe my success in Zinc WW removal is careful sorting and when melting, removing all clips from atop the melted alloy just as soon as the alloy is molten.
TYPE METALS:
• I estimate that I have gathered approximately 5 tons of type metals over the past 50 yrs. These metals have normally been identified as spacers, linotype (slugs and ingots), stereo type Ingots, monotype and foundry type blends (lots of single letter material dumped in 5 gal. buckets).
• Following are results of recent XRF analysis of the various metals usually samples of 1,000 lb lots of these metals.
o Foundry / Mono blend: Pb = 60.5% to 64.8%, Sb = 21 % to 25 %, Sn = 10.8 % to 12.6 %.
o Lino blend (22 lb ingots and slugs): Pb = 83 % to 85 %, Sb 12 % and Sn 3.5 – 4 %.
o Stereotype Ingots
I have found several “Imperial Stereo Metal” ingots over the years with XRF Pb = 72.5%, Sb = 16%, Sn = 11.5 %.
o Spacer Metal: Spacer materials have varied widely in their Pb, Sb and Sn content my experience has been Pb = 84 % to 85%, Sb 9 % - 12% and Sn around 4 %.
LEAD TIN SOLDERS:
• Normally I find solders in the form of 1 lb bars and pieces of solder wire spools.
• The National Lead bars labeled:
o 111 = 50 % Sn and 50 % Pb.
o 666 = 39 % Sn, 1 % Sb and 40 % Pb
• The pieces of solder spools I gathered were mostly rosin core and acid core. A collection of over 100 lbs of this solder melted into one batch, yielded about 40 % Sn with 60 % Pb per XRF.
• Bell Wiping solder = 38% Sn with 62 % Pb per XRF
• LEAD FREE SOLDERS:
o These have normally been reported by the Mfg. as 95 % Sn, 5 % Sb with some Silver and other metals present in small amounts by certain Mfgrs.
RADIATION SHIELDING:
• Normally the lead sheeting found in X-Ray room walls is very nearly pure Pb per XRF.
• Nuclear medicine containers:
o These containers, used to shield nuclear (radioactive) medicines, have been either pure Pb or an alloy of about 97.5 % Pb and 2.5 % Sb per XRF.
My understanding as that these Nuclear Medicine Pigs normally contain isotopes which decay rapidly and that the health care institution using such "Pigs" must hold them until the ionizing radiation reaches background levels for 60 days. In other words there are no radiation risk to us folks melting the Pigs.
MISCELLANEOUS LEAD OBJECTS:
• Misc. Lead sheet objects such as roof vent “boots”, shower pans, rings from cast iron sewer pipes, etc have almost always been + 99 % pb per XRF
RECLAIMED LEAD SHOT:
• I have worked with several hundred pounds of reclaimed shot. This material was difficult to melt consuming a lot of time and fuel and repeated fluxing to produce clean ingots.
• The material was between 2% and 6 % Sb with the remainder Pb per XRF.
• I guess the shot was a blend of “Chilled Shot” and “Magnum Shot”.
RECLAIMED RANGE BULLETS:
• I have no experience with reclaimed range bullet metals.
PEWTER:
• I have collected and melted about 1 ton of pewter metal. As you might imagine just about any pewter object I could identify and melt was included.
• In general if the pewter has a dull grey patina (pre melt) it may contain small amounts of Pb with the remainder normally Sn, Cu (Copper) and in some cases a little Sb.
• Bright shiny silver pewters are normally + 95 % Sn with the remainder Cu and on occasion Sb.
POWDER COATING:
• In the last couple of years I have experimented with Eastwood Lime Green Hot Coat, Shake and Bake Application method.
• While the application of this coating results in a greater investment of time, I sure like the finished product for cleanliness with good performance.
MY OBSERVATIONS:
• As you can see the expected values of the Pb, Sb and Sn present in many base metal alloys varies somewhat from the values reported in much of the literature.
• My experience is that it is impossible to determine the elements present in any item or comingled lot of items without correct sampling and XRF analysis.
• Test such as thumb nail penetration, pencil hardness, dull thud vs ring when metal is dropped on concrete, gold colored patina (tin presence), Saeco, Lee, Brinnell hardness test, etc, etc, etc, offer very little information regarding the combination and percent of elements contained in the sample.
• Since I started using XRF on my source metals going into a desired alloy the quality of my alloys and cast boolits have improved considerably.
• I believe if you want to be reasonably sure of the amount of the desired elements (Pb, Sb, Sn) in your alloy, you must have reliable XRF analysis for each of you input metals.
I hope these ramblings of an old man are helpful
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