By Jeff Brown
So you have been to see the local tyre shop and got yourself a big old bucket of wheel weights and now you are going to cook up and shoot up a storm. After all, wheel weights are a fantastic source of bullet casting alloy made up of a special blend of lead, tin and antimony and we are told by every piece of shooting literature we pick up so it must be true right? Pain me as it does to rain on your parade the answer is an emphatic NO! YES, wheel weights CAN be a source of very good cast bullet alloy but all that glitters is not gold and all that comes of wheel rims is not lead as I have been experiencing lately.
A veritable potpourri.
There are two factors conspiring against shooters when it comes to recycling wheel weights for the purpose of casting projectiles.
1 - Environmental:
Due to environmental concerns lead is an every diminishing resource in our modern world. Those who still drive very old cars will know of this from when lead (tetra-ethyl lead) was removed from petrol some years. Hunters of water fowl are now limited to “non toxic” shot except under special conditions. In various places in the world the perceived need to remove lead from the environment is impacting on the use of traditional wheel weights also and increasingly these are being replaced with ferrous and zinc substitutes. See the following regarding the EU:
“An estimated 70,000 tons a year of lead is used worldwide in the manufacture of wheel weights….”
“The European Union has banned the use of lead wheel weights, effective July 2005, so alternatives made of zinc, steel and other materials have rapidly become standard practice in Europe, but are very new in the United States, where the need for regulation is just becoming clear.”
This bodes especially poorly for cast bullet shooters as one of the most important supplies of bullet metal is drying up. Evidence of this was in the last lot of wheel weights I acquired. As I was sorting through the bag of weights I noticed that some where a different size, shape and colour to what is normal. See fig 1. The batch was small so I sorted all the weights on my bench the result was four distinct piles consisting of traditional lead weights, plastic coated weights with holes in, large but less dense weights and peripheral oddments of values, valve caps etc. Fig 2. The lead weights made up only half of the allocation to my horror. This is definitely something to watch for if you are, God forbid, BUYING wheel weights are you may end up paying twice as much as you think.
A veritable potpourri.
There are two factors conspiring against shooters when it comes to recycling wheel weights for the purpose of casting projectiles.
1 - Environmental:
Due to environmental concerns lead is an every diminishing resource in our modern world. Those who still drive very old cars will know of this from when lead (tetra-ethyl lead) was removed from petrol some years. Hunters of water fowl are now limited to “non toxic” shot except under special conditions. In various places in the world the perceived need to remove lead from the environment is impacting on the use of traditional wheel weights also and increasingly these are being replaced with ferrous and zinc substitutes. See the following regarding the EU:
“An estimated 70,000 tons a year of lead is used worldwide in the manufacture of wheel weights….”
“The European Union has banned the use of lead wheel weights, effective July 2005, so alternatives made of zinc, steel and other materials have rapidly become standard practice in Europe, but are very new in the United States, where the need for regulation is just becoming clear.”
This bodes especially poorly for cast bullet shooters as one of the most important supplies of bullet metal is drying up. Evidence of this was in the last lot of wheel weights I acquired. As I was sorting through the bag of weights I noticed that some where a different size, shape and colour to what is normal. See fig 1. The batch was small so I sorted all the weights on my bench the result was four distinct piles consisting of traditional lead weights, plastic coated weights with holes in, large but less dense weights and peripheral oddments of values, valve caps etc. Fig 2. The lead weights made up only half of the allocation to my horror. This is definitely something to watch for if you are, God forbid, BUYING wheel weights are you may end up paying twice as much as you think.
The plastic coated weights appeared to be zinc on the interior as were a few flat examples with the letters “Zn”, the chemical symbol for zinc, stamped on them. With the aid of a magnet the large weights proved to by ferrous (IE: iron/steel) and stuck to the magnet like the proverbial to a blanket. See fig 3. Gram for gram these were much larger in mass than their lead cousins. See fig 4. Ferrous content, while an annoyance, is not a major problem to the caster as these weights will readily rise to the surface of lead and may be skimmed off with the steel clips. Ultimately they are best sorted out of the metal prior to smelting as there is little to be gained from heating them for the sake of removing them later. Likewise the inclusion of ferrous weights only diminishes the volume available for lead smelting which is the point of the exercise. Still, ferrous is not a major concern to us.
Zinc on the other hand is a nasty customer to have in your lead pot. Should zinc reach a critical level in your lead alloy, much the same as aluminium, the bullets will not form at all well due to the surface tension created by the contaminate. The only options are the discard the metal or risk adding additional “good” alloy to try and dilute the zinc down to a degree that has no effect. I suspect I have had this in the past with a batch of alloy that would not cast well and managed to dilute the alloy down with good results however it is always a gamble to “throw good alloy after bad”. One way to prevent zinc contaminating your lead alloy other than sorting is the control the temperature of your ‘melt’. Wheel weight is molten at 505F, pure lead at 621F and zinc at 787F. By keeping the alloy temperature in the wheel weight/lead range the zinc will not melt into the alloy but instead float to the surface on fluxing presenting itself for skimming off.
Zinc on the other hand is a nasty customer to have in your lead pot. Should zinc reach a critical level in your lead alloy, much the same as aluminium, the bullets will not form at all well due to the surface tension created by the contaminate. The only options are the discard the metal or risk adding additional “good” alloy to try and dilute the zinc down to a degree that has no effect. I suspect I have had this in the past with a batch of alloy that would not cast well and managed to dilute the alloy down with good results however it is always a gamble to “throw good alloy after bad”. One way to prevent zinc contaminating your lead alloy other than sorting is the control the temperature of your ‘melt’. Wheel weight is molten at 505F, pure lead at 621F and zinc at 787F. By keeping the alloy temperature in the wheel weight/lead range the zinc will not melt into the alloy but instead float to the surface on fluxing presenting itself for skimming off.
The need to carefully sort ‘new’ batches of wheel weights in now a very real priority and whilst this is time consuming the benefits outweigh the consequences of not sorting especially in terms of the potential impact of zinc weights.
Whether we agree or disagree with the environmental motivation for this change there will be no turning back and non lead wheel weights are here to stay. I personally believe that wildlife is at much greater risk from the wheel upon which the weight is mounted than the lead in the weight itself. My own research shows that the number of hedgehogs killed by ingesting lead is infinitesimally smaller than those made two dimensional by vehicles tyres! Likewise with the tetra-ethyl lead/benzene in petrol scenario. A good friend of mine told me this: Benzene is known to cause cancer whereas lead will only make you stupid. He’d rather be stupid than dead. I bit my tongue. HHHMMM.
2 – Composition.
‘Deep Thought’, the immense computer in “The Hitchhikers’ Guide to the Galaxy” calculated that the ultimate answer to the ultimate question was 42. What this calculation was based on nobody was entirely sure and the composition of lead wheel weights falls into this category also.
The bottom line is that nowhere in the world anymore is there a standard formula for the blend ratio of elements which make up wheel weight alloy. Further to this the numbers that are quoted in relevant literature frequently do not match. See the following table noting seven different references:
Whether we agree or disagree with the environmental motivation for this change there will be no turning back and non lead wheel weights are here to stay. I personally believe that wildlife is at much greater risk from the wheel upon which the weight is mounted than the lead in the weight itself. My own research shows that the number of hedgehogs killed by ingesting lead is infinitesimally smaller than those made two dimensional by vehicles tyres! Likewise with the tetra-ethyl lead/benzene in petrol scenario. A good friend of mine told me this: Benzene is known to cause cancer whereas lead will only make you stupid. He’d rather be stupid than dead. I bit my tongue. HHHMMM.
2 – Composition.
‘Deep Thought’, the immense computer in “The Hitchhikers’ Guide to the Galaxy” calculated that the ultimate answer to the ultimate question was 42. What this calculation was based on nobody was entirely sure and the composition of lead wheel weights falls into this category also.
The bottom line is that nowhere in the world anymore is there a standard formula for the blend ratio of elements which make up wheel weight alloy. Further to this the numbers that are quoted in relevant literature frequently do not match. See the following table noting seven different references:
Reference source: | Pb% | Sn% | Sb% | As% | BHN |
Lyman Cast Bullet Handbook 3rd Edition | 95.5 | 0.5 | 4.5 | 0 | n/a |
Lyman Reloading Handbook 45th Edition | n/a | n/a | ~9 | n/a | n/a |
Cast Bullets for Beginner & Expert, Joe Brennan - issued by the Cast Bullet Association. | 95.5 | 0.5 | 4.0 | 0 | 9 |
93.55 | 0.25 | 3.0 | 0.17 | 9 | |
Los Angeles Silhouette Club web site, www.lasc.us (clip on) (stick on) | 95.25 | 0.5 | 4.0 | 0.25 | 12 |
100 | 0 | 0 | 0 | 5 | |
Handloader Mag., Custom Bullet Alloy, John Zomanek | 95.5 | 0.5 | 4.0 | 0 | n/a |
Handloader Mag., Determining Bullet Alloys, Rick Jamison | 89.5 | 1.5 | 9.0 | 0 | n/a |
Handloader Mag., Determining Alloy Composition, Dave Scovill | 90.0 | 1.0 | 9.0 | 0 | 14.5 |
VARIANCE | 10.5 | 1.0 | 6.0 | 0.25 | 9.5 |
Legend: Pb – lead Sn – tin Sb – antimony As – arsenic BHN – Brinell Hardness number
Not even Lyman, one of the most foremost authorities on bullet casting, can agree. In the Lyman Reloading Handbook, 45th Edition, wheel weight is stated to contain “about” ( ~ ) 9% antimony (Sb) which is “about” 5% more than the 3rd Edition of the Cast Bullet Handbook quotes. Joe Brennan, in his text, Cast Bullets for Beginner & Experts, shows two different formulations, one containing arsenic (As) and the other without. Even the good old boys at Handloader Magazine can’t agree on the formula.
Of particular interest and real relevance is that Joe Brennan and LASC are the only authorities to mention arsenic in the mix. Arsenic is the essential element in heat treating wheel weights in order to dramatically increase the Brinell Hardness Number (BHN). Without this one element the heat treating process is void. As we know that heat treating wheel weight alloy to increase the BHN definitely works there must be arsenic present. I am presently successfully oven heat treating wheel weight alloy to 33 BHN.
In addition to no concurrence on a formula there is a disparity in the stated BHN. Sb is the determining factor in the hardness of wheel weight and the greater the amount present the harder the alloy. Assuming the data in table 1. is correct the BHN’s appear correspondingly so however as there is little agreement any of the data all the numbers become very nominal.
Just when the reader is beginning to think that ignorance is bliss and this can’t get any worse we discover that ‘stick on’ wheel weights are considered to be pure lead. ‘Stick on’ wheel weights are used on mag wheels where it is not possible to fit a traditional ‘clip on’ variety. ‘Stick ons’ are thick strips of very soft lead, basically pure, marked in weight graduations and adhesive backed. See fig 5. Again there is a huge discrepancy in table 1. as only the LASC make ANY reference to this variety of alloy - it clearly exists as approximately half of the wheel weights by volume I sorted on the weekend were of the this nature. As pure lead is taken to be ~ 5 BHN and ‘clip on’ wheel weight ~ 12 BHN (average from table 1.) we are left with a huge different in hardness and it is this factor of hardness which dictates the alloys ability to withstand pressure and velocity. Pure lead can be driven up to pressures of 13000 PSI where as an alloy of BHN may be pushed to 25000 PSI so not realising the difference in the two types of metal can and will lead to differing and disappointing results.
Do not despair.
About now I can guess some of you are considering taking up a different hobby as “The Cast Bullet Kid” has now made your previously peaceful existence a misery of worry and chemical calculations. Fear not dear caster for all is not lost. Wheel weights can still be the casters best friend if we simply adhere to a few precautionary steps along the way.
1) Upon receipt of “lots” of wheel weight alloy thoroughly sort each and every piece. ‘Stick on’ weights are easily identified and can be separated off with a little effort as can the foreign bodies and little gems the tyre man throws in his bucket. ‘Clip on’ weights will need to be sorted with a little more care but with a bit of practice the different ‘clip on’ styles are picked up without busting a gut. Lead tends to make a “clunk” sound when dropped on concrete in contrast to zinc and steel which tend to “ching”. The physical weight of each is a dead give away also.
2) Dispose of the non lead alloy weights with a degree of haste so they do not lie about and risk becoming mixed back in with your valuable lead alloy again. Memories do strange things over time which is why I mark all my bullets and alloys.
3) Batch your alloy in as larger amount as is possible. I have my late father’s old Primus stove running on kerosene. You’d be surprised how far a litre of kerosene will go melting down lead. I set up outside under cover (is case it rains during the process) and fire up the old Primus batching approximately 25kg of alloy at the time. See fig 6. This process serves three purposes.
About now I can guess some of you are considering taking up a different hobby as “The Cast Bullet Kid” has now made your previously peaceful existence a misery of worry and chemical calculations. Fear not dear caster for all is not lost. Wheel weights can still be the casters best friend if we simply adhere to a few precautionary steps along the way.
1) Upon receipt of “lots” of wheel weight alloy thoroughly sort each and every piece. ‘Stick on’ weights are easily identified and can be separated off with a little effort as can the foreign bodies and little gems the tyre man throws in his bucket. ‘Clip on’ weights will need to be sorted with a little more care but with a bit of practice the different ‘clip on’ styles are picked up without busting a gut. Lead tends to make a “clunk” sound when dropped on concrete in contrast to zinc and steel which tend to “ching”. The physical weight of each is a dead give away also.
2) Dispose of the non lead alloy weights with a degree of haste so they do not lie about and risk becoming mixed back in with your valuable lead alloy again. Memories do strange things over time which is why I mark all my bullets and alloys.
3) Batch your alloy in as larger amount as is possible. I have my late father’s old Primus stove running on kerosene. You’d be surprised how far a litre of kerosene will go melting down lead. I set up outside under cover (is case it rains during the process) and fire up the old Primus batching approximately 25kg of alloy at the time. See fig 6. This process serves three purposes.
i. Ensures consistency over a sample of alloy. The bigger the batch the better.
ii. Provides an opportunity to add other elements to the alloy. I have started adding approx. 2% tin to my ‘clip on’ wheel weight in order to promote positive mould fill out as tin decreases surface tension and helps the lead flow. The addition of some linotype can increase the antimonial content and increase hardness of air cooled metal. One recipe for Lyman No.2 alloy is quoted at 9 to 1 ratio, clip on wheel weights and 50/50 lead/tin bar solder. This supposedly gives a blend of 95% PB, 5% Sn, 5% Sb but given what we learned from table 1. who would know?
iii. Cleans the alloy on all impurities and foreign bodies IE: steel clips. I remove the clips as they surface then flux the alloy to ‘death’ using beeswax. The result is piles of bright, clean ingots.
ii. Provides an opportunity to add other elements to the alloy. I have started adding approx. 2% tin to my ‘clip on’ wheel weight in order to promote positive mould fill out as tin decreases surface tension and helps the lead flow. The addition of some linotype can increase the antimonial content and increase hardness of air cooled metal. One recipe for Lyman No.2 alloy is quoted at 9 to 1 ratio, clip on wheel weights and 50/50 lead/tin bar solder. This supposedly gives a blend of 95% PB, 5% Sn, 5% Sb but given what we learned from table 1. who would know?
iii. Cleans the alloy on all impurities and foreign bodies IE: steel clips. I remove the clips as they surface then flux the alloy to ‘death’ using beeswax. The result is piles of bright, clean ingots.
If you are content to produce a softer alloy by mixing the ‘clip on’ and ‘stick on’ weighs together I suggest you do so separating them initially then weighing out the individual amounts of each to a known weight. Ideally each metal should be batched first to remove dirt and foreign objects per point iii above then combined to produce the final bullet alloy.
4) Record the details of each batch and label the container they are stored in. DO IT! You will forget. If you have a hardness tester conduct tests also, record the results, date the records and fasten to the container the alloy is in. This way the alloy is identified and the hardness is noted and can be monitored for age hardening or softening.
4) Record the details of each batch and label the container they are stored in. DO IT! You will forget. If you have a hardness tester conduct tests also, record the results, date the records and fasten to the container the alloy is in. This way the alloy is identified and the hardness is noted and can be monitored for age hardening or softening.
It goes without saying that lead can be a very unpleasant substance to have rattling around in your system. When doing any casting but ESPECIALLY when batching alloy it is particularly prudent to observe the following guidelines for safety and personal longevity:
ü Work in a well ventilated area – outside is best. Batching alloy is a filthy business that produces lots of smoke and fumes containing Lord only knows what. Stay up wind.
ü Wear eye protection as lead can and does splash and ‘spit’.
ü Wear gloves that will withstand momentary exposure to molten lead. I like close fitting light leather gloves that provide protection but maintain ‘feel’. Ten dollars at the Warehouse.
ü Long pants and stout footwear are essential. Leave the jandals for the beach.
ü Try and work under cover if there is a chance of rain. Water and lead do not mix. Likewise work away from water sources if you can.
ü Youngsters are more prone to the toxic nature of lead than us older folk due to their smaller size. Make sure the kids are somewhere else.
ü When fluxing try and ignite the smoke/fumes from the flux (IE: beeswax) with a match. Flame is better than smoke on your respiratory system and keeps the neighbours happier. Beeswax fumes burn off cleanly and readily.
ü Work on a surface that allows you to clean up afterwards and remove waste products. Better for the environment. Will someone PLEASE think of the environment?
So there it is then. Bit like the old riddle – when is a door not a door? When it’s ajar. Yes, you’ve got wheel weights. No, they may not be all lead based. Yes, some are lead alloy. No, the lead alloy weights do not all contain Sn, Sb and As and those that do could have any ratio of these. Yes, the ‘clip on’ variety are harder. No, ‘stick on’ weights will not make good high pressure bullets. Yes, batching will help consistency and allow for adding other elements. No, zinc is not lead’s friend. Yes, much good shooting can be had from salvage wheel weight and very respectable bullets may be cast from this resource.
ü Work in a well ventilated area – outside is best. Batching alloy is a filthy business that produces lots of smoke and fumes containing Lord only knows what. Stay up wind.
ü Wear eye protection as lead can and does splash and ‘spit’.
ü Wear gloves that will withstand momentary exposure to molten lead. I like close fitting light leather gloves that provide protection but maintain ‘feel’. Ten dollars at the Warehouse.
ü Long pants and stout footwear are essential. Leave the jandals for the beach.
ü Try and work under cover if there is a chance of rain. Water and lead do not mix. Likewise work away from water sources if you can.
ü Youngsters are more prone to the toxic nature of lead than us older folk due to their smaller size. Make sure the kids are somewhere else.
ü When fluxing try and ignite the smoke/fumes from the flux (IE: beeswax) with a match. Flame is better than smoke on your respiratory system and keeps the neighbours happier. Beeswax fumes burn off cleanly and readily.
ü Work on a surface that allows you to clean up afterwards and remove waste products. Better for the environment. Will someone PLEASE think of the environment?
So there it is then. Bit like the old riddle – when is a door not a door? When it’s ajar. Yes, you’ve got wheel weights. No, they may not be all lead based. Yes, some are lead alloy. No, the lead alloy weights do not all contain Sn, Sb and As and those that do could have any ratio of these. Yes, the ‘clip on’ variety are harder. No, ‘stick on’ weights will not make good high pressure bullets. Yes, batching will help consistency and allow for adding other elements. No, zinc is not lead’s friend. Yes, much good shooting can be had from salvage wheel weight and very respectable bullets may be cast from this resource.