Copper in lead alloy???

62chevy

Active Member
#1
OK is copper of about 1% worth it? Does it really make a tougher bullet? And can you shoot them faster than say #2 alloy?
 

Brad

Administrator
Staff member
#3
I think you can push any alloys a faster than you can Lyamn #2.
Copper will make a tougher bullet. Not just to allow better velocity but also to help keep the bullet together on impact.
 

Brad

Administrator
Staff member
#5
Run it closer to 725 and it will be about right. Listen to the pot. It the spout is plugging or freezing then increase the heat. No exact science, just observe what is happening and adjust accordingly. The 725 temp is where I ran mine but I used a ladle.
 

62chevy

Active Member
#6
Run it closer to 725 and it will be about right. Listen to the pot. It the spout is plugging or freezing then increase the heat. No exact science, just observe what is happening and adjust accordingly. The 725 temp is where I ran mine but I used a ladle.
I use a ladle too with an RCBS pot on a hot plate. 650 is a full pot and 675 is less than half. Can break out the Coleman stove that likes to get up to 750 on the lowest setting then switch to the hot plate seams my molds love the lower temps.
 
#7
OK is copper of about 1% worth it? Does it really make a tougher bullet? And can you shoot them faster than say #2 alloy?
It is to me, it does make the bullet tougher and you can shoot it faster and it will go down range in one piece rather than drift off in a cloud of gray looking smoke. I initially had problems in .30 and 6mm comming apart at higher speeds. Since I started using copper addition I have not even had that issue even one time and I have driven both to point that cases started showing signs of OP and bolts were hard to operate ( way above what I should have). Easy way to test is get a pound of the copper babbit from roto metals. Nice and clean and known amount so no question on tests.
 
#9
Out of curiosity I googled "copper melting temp." and got 1,984 degrees Fahrenheit. How do you alloy that with a lower lead temperature? Or does it just stay suspended in the lead? I've read lead vaporizes at about 1,000 degrees and I don't plant to heat my alloys that high...
 

Eutectic

Active Member
#10
Lead alloys are some of the most interesting alloys. They kind of 'march to the beat of their own drum'..... Take our trinary (lead, tin, antimony) alloy we commonly use. The lowest melt point in this alloy is right at linotype and it has about 12% Antimony.!! It is eutectic at about 480°F and homogeneous! Now pure Antimony melts at 1167°F and there is 12% of it in linotype! I believe copper is alloyed in similarly but in smaller percentages. I've never used copper in lead alloys but a lot of very smart people do. I want to try in in my .35 Whelen someday! Someone will give you info on metallurgy of copper in lead alloys so I'll watch!

Pete
 

popper

Well-Known Member
#11
is copper of about 1% worth it? I've gone to 2%, HT and BHN > 36 in a day. Yes they shoot fine. 0.5% is enough. Shot a 165 40SW (950 or so) into a hard rock pile. IIRC, 98% weight retension. Complete pass through stem to stern on a 150ish pig. Bunch of bone sticking out of the gullet. So far I've never recovered any from the 308W and i've tried. Just cut a trench in the rock pile.. Cast about 750F for a Lee.
 

John

Active Member
#12
The easiest way to add it to your PB is buy Rotometals copper babbit. Then figure the percentage you want to add to 50 lbs and begin your mix. With trying different fluxes you will always be unsure about the percentages.
 

Ian

Well-Known Member
#13
Out of curiosity I googled "copper melting temp." and got 1,984 degrees Fahrenheit. How do you alloy that with a lower lead temperature? Or does it just stay suspended in the lead? I've read lead vaporizes at about 1,000 degrees and I don't plant to heat my alloys that high...
Like Eutectic wrote, these alloys are unique. The metals sort of dissolve in each other, rather than melt per se. Solid copper dissolves in molten tin and the resulting alloy still has a low melt point. The tin/copper can be dissolved in bullet alloy. Of course there are saturation limits which are dependent on temperature (same as salt and water), but depending on percentages of each of four or five metals together in the pot, interesting things happen as the alloy begins to cool and different phases of crystallization occur. The dendrite lattice structure is what adds strength to the basic lead alloy.
 

fiver

Well-Known Member
#14
the dendrite lattices and the boundary layers.

it's still impressive that .5% copper can almost completely surround 2-3% antimony and even more astonishing is it will do it when you water drop the alloy and lock the unformed SbCuSn chains all throughout the alloy into a whole other splotchy/broken alloy matrix.
leave the cu out and air cool and you get a PbSbSnPb type chain formed throughout the alloy.
anyway the copper bonds in with the Sb for the most part even though it needs the Sn [at about a 3 to 1 ratio] to get into solution using some of the home methods.
it helps keep the antimony crystals from breaking down under pressure which helps hold the lead in place/shape not allowing it to move as much/as soon.
 

Ian

Well-Known Member
#16
Try to find a copy of the Lyman cast bullet handbook, third edition, if you don't already have one. It contains an article with excerpts from the Metals Handbook which address the phase and crystallization characteristics of ternary alloy and also has a brief discussion of the effects of zinc at different temperatures/saturation levels and an even more brief mention of calcium and a few other contaminants. Copper adds another dimension to all that. Arsenic and sulphur as grain refiners are also discussed. If you can read that section over and over until you thoroughly understand it, you'll be ahead of the game understanding how bullet alloys work in a gun.
 

fiver

Well-Known Member
#17
and you'll have a headache for about 2 weeks.
I probably read that portion of the book 50 or more times, at least enough times that the binding was wearing through and the pages were falling out.
it still took a while for things to sink in and make sense.


Popper has put some links up on the site here that have made me sit there and think things through for a couple of hours too, but after looking at them and reading and re-reading things it started sinking in even better how the different alloys were working.
not just how they come from the mold or how they reacted to being heat treated.
but being able to predict and think through how they would react under pressure in the rifle.
it's not always clear what a high or low BHN alloy will do unless you break down each constituent and then put the pieces together.
just because an addition acts one way on it's own doesn't mean it will act the same way in the presence of 1 or 2 other additions or with quench cooling when it's subjected to pressure, flow, and rotational stress.
then the amount of it in the alloy can allow it to act in a whole other way [depending on the amount of other additives]
a little is good so more must be better is well,,, sometimes not true and sometimes it is.
 
#18
I tried to read the chapter about alloy/lead in my 3rd Edition, but was unable to get much more than a headache out of it. I'm not stupid, as I served a 5 year apprenticeship as an Auto Electrician with class room study/teaching 2 nights per week for the duration and "specialized" in Heavy Equipment Electronics (a lot of computerized "fly by wire" control and safety systems on heavy construction equipment), with a large west coast city utility, and completed 3 years study to become certified as an Addictions Counselor. I guess I'll just shut up and read, as I seen nuttin' I can contribute...
 

Ian

Well-Known Member
#19
It's difficult to grasp because the concepts are very abstract and require developing new neural pathways to fully visualize. Tough for a sequential or logical thinker/problem solver. Small bites, take small bites. It will eventually start to make sense, and when it does, a lot of the esoteric bs some of us here ramble on about sometimes might start to click.
 

RicinYakima

High Steppes of Eastern Washington
#20
mikid, A lot of it is the words that aren't used outside of science. Having taught chemistry to Police Officers, Firefighter, EMT's and other emergency responders, it is not natural or "common sense". Visualizing small relationships is hard to do without having a hands on testing lab to let you see what is happening. Ric