RepackboxTitan ReloadingLee PrecisionLoad Data
RotoMetals2Inline FabricationMidSouth Shooters SupplyWideners
Reloading Everything
Page 1 of 5 12345 LastLast
Results 1 to 20 of 90

Thread: Alloying Copper into Lead-Tin

  1. #1
    Boolit Grand Master 303Guy's Avatar
    Join Date
    Oct 2008
    Location
    New Zealand
    Posts
    9,078

    Alloying Copper into Lead-Tin

    It's so easy it should be illegal! After reading and talking and looking up on the 'net, I decided to try adding copper to an already pretty good pot of alloy which is presumably lead-tin.

    I took a piece of copper I had, tinned it with soft electical solder and submerged it into the melt. The melt has Kitty Litter on top and I fluxed with a stick, leaving a carbon rich layer close to the metal surface. The copper dissolved into the melt and that was it!

    End results - benefits or changes? Well, the casting seem harder than before and also seem to harden quicker. There is no loss of ductility. The most noticable difference is the color of the sprue plugs. Very colorful whereas before they were shiny silver. There is a slight difference in the appearance of the castings but only slight. More than that, I don't know. I'll see how the castings harden or toughen or even soften over time.
    Last edited by 303Guy; 07-04-2010 at 01:55 PM.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

  2. #2
    Boolit Master
    Join Date
    Oct 2009
    Posts
    1,839
    Quote Originally Posted by 303Guy View Post
    It's so easy it should be illegal! After reading and talking and looking up on the 'net, i decided to try adding copper to an already pretty goold pot of alloy which is presumably lead-tin.

    I took a piece of copper I had, tinned it with soft electical solder and submerged it into the melt. The melt has Kitty Litter on top and I fluxed with a stick, leaving a carbon rich layer close to the metal surface. The copper dissolved into the melt and that was it!

    End results - benefits or changes? Well, the casting seem harder than before and also seem to harden quicker. There is no loss of ductility. The most noticable difference is the color of the sprue plugs. Very colorful whereas before they were shiny silver. There is a slight difference in the appearance of the castings but only slight. More than that, I don't know. I'll see how the castings harden or toughen or even soften over time.
    I find this very interesting. How much copper (weight) did you add to the lead mix and how much of a lead mix (weight)?
    Why did you "tin" the copper before adding?

    Somewhere I read when pouring bullets from an alloy like this (babbitt) it should be continuously stirred to keep the copper in "suspension".

    Really interested in what the more experienced guys have to say. Thanks for sharing your experiment/information.

  3. #3
    Boolit Buddy robroy's Avatar
    Join Date
    Jan 2009
    Posts
    357
    I've been in a dither about getting copper melted with what I have at hand to the same end. Seems you've found the solution (no pun intended but those are the best kind). What are the weights of components?

  4. #4
    Boolit Buddy
    Join Date
    Dec 2009
    Location
    SE Michigan
    Posts
    451
    I'm wondering at what temperature the melt was and what it will take to remelt it?

  5. #5
    Boolit Grand Master 303Guy's Avatar
    Join Date
    Oct 2008
    Location
    New Zealand
    Posts
    9,078
    OK. Firstly, I did not jump in blind-folded. I did do some research first.

    Copper is slightly soluble in lead and readily soluble in tin. The idea of tinning the copper is to put it in contact with the melt. Without tinning, it is insulated by a layer of oxide. So, once tinned, it will dissolve up and until saturation point at the temperature of the melt. What it does is the same as tin and that is to reduce the melting poing of the lead and hense improve it's fluidity - the same as tin does. Upon freezing, it adds toughness to the lead. Too much copper and it precipitates out and that is where problems occur. I'm looking for something like less than half a percent copper (I forget the solubility limit and couldn'd find it on the net with a quick search). As for actual quantities - who knows? I just guessed at an amount. I can work it out but I don't have a scale capable of measuring the lead but I can measure it's volume. I just haven't done it yet as this was a test to dissolve the copper. It's in there - it makes for very a pretty coloured oxide skin. And a nice boolit! One that hardens quicker than before the copper.

    Melt temperature? Normal casting temp.

    The fired boolit was a cat sneeze load into soft sand. It's expansion belies the apparent hardness of the boolit. (Unless it's a lot faster than its supposed to be!) 100% weight retention.

    The sprew was from without copper.
    Last edited by 303Guy; 06-19-2010 at 02:28 AM.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

  6. #6
    Boolit Master trk's Avatar
    Join Date
    Mar 2005
    Location
    Mountains of Virginia
    Posts
    617
    Interesting1 I have a bunch of lead-free electronic solder scrap. Started as 96.5 tin, 3%silver and 0.5%copper.
    trk
    aka Cat Whisperer
    Chief of Smoke, Pulaski Coehorn Works and Skunk Works
    N 37.05224 W 80.78133 (front door +/- 15 feet)

  7. #7
    Boolit Master GabbyM's Avatar
    Join Date
    Mar 2008
    Location
    Central Illinois
    Posts
    3,870
    This is something I'l have to try.
    Had some material with copper once. Duh old brain. Whaterver it was it made great bullets.
    Have tried dropping copper wire onto the melt but it just lays there. Tin it then place it under clay.

    When I tried kitty litter it seamed to draw off my alloy metal. bullets got softer as the pot lingered with clay on top. But that was in no way a scientific test.

  8. #8
    Boolit Grand Master 303Guy's Avatar
    Join Date
    Oct 2008
    Location
    New Zealand
    Posts
    9,078
    Tin it then place it under clay.
    Actually submerge it in the melt. It dissoves slowly.

    lead-free electronic solder scrap. Started as 96.5 tin, 3%silver and 0.5%copper.
    I think the copper and silver are to lower the melting point.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

  9. #9
    Boolit Master
    lwknight's Avatar
    Join Date
    Nov 2009
    Location
    Fort Worth, Texas where the west begins
    Posts
    3,416
    I thought that the silver was just improve the continuity so that the connections would not get as hot under a load.
    Sent from my PC with a keyboard and camera on it with internet too.
    Melting Stuff is FUN!
    Shooting stuff is even funner

    L W Knight

  10. #10
    Boolit Master sagacious's Avatar
    Join Date
    Sep 2009
    Location
    US West Coast
    Posts
    1,120
    The silver doubtless improves electical conductivity. It also strengthens the solder and believe it also prevents tin-whisker formation, which is a very serious problem when there's no lead in there.

    The copper further strengthens the solder and likely increases conductivity. It could also increase the corrosion-resistance, decrease galvanic differential with copper plumbing, decrease solubility and erosion of joints in soft-water areas, and reduce copper-scavenging in wave-soldering applications. Often adding a very small amount of one element to a solvent reduces the aggressiveness the solvent to dissolves more.

    This stuff can get pretty complicated. It's another example of very small changes having significant effects.

  11. #11
    Boolit Master madsenshooter's Avatar
    Join Date
    Jan 2006
    Location
    Upper Appalachia, SE Ohio
    Posts
    3,020
    Ideal #1 alloy was 3% Cu. I've been using a lead based babbitt, Stonewall Babbitt, that contains .5% Cu. I use it mainly to add Sn and Sb to pure lead. How would Cu decrease the melt temp? Can't see that happening.

  12. #12
    Boolit Master
    lwknight's Avatar
    Join Date
    Nov 2009
    Location
    Fort Worth, Texas where the west begins
    Posts
    3,416
    If lead melts at 620 and 4% tin added lowers it to 550 then you would think that adding 12% antimony would raise it but he opposite happens. It will melt at about 480. ( btw: thats lino)
    So why couldn't a small amount of copper actually lower the melting point.

    One thing for sure is that too much copper will make your tin into brass which certainly don't melt easily compared to tin or even lead.
    Sent from my PC with a keyboard and camera on it with internet too.
    Melting Stuff is FUN!
    Shooting stuff is even funner

    L W Knight

  13. #13
    Boolit Master sagacious's Avatar
    Join Date
    Sep 2009
    Location
    US West Coast
    Posts
    1,120
    Quote Originally Posted by madsenshooter View Post
    How would Cu decrease the melt temp? Can't see that happening.
    Keep looking, you'll see it once you've read this post. Many metal combinations (alloys) that are even slightly miscible have a eutectic point.

    If there is a eutectic point, then there's a point where adding some of the higher melting point metal actually reduces the melting point of the lower melting-point metal.

    It's not really a "melting-point" addition/subtraction situation. It's the chemical and thermodynamic properties of the mixture that determine the melting point. One cannot just say, OK, it's 90% tin and 10% copper, so the melting point must equal to 90% of tin's melting point plus 10% of copper's melting point. Doesn't work that way with most metals. Does work that way with gold/silver alloy, but that's not the usual situation.

    Consider that the melting/freezing point of water is 32*F. Consider also that the melting point of salt is way high. But mix salt into water and the melting/freezing point plummets to something like -6*F. Salt and water actually have a eutectic point, which is about 25% salt and 75% water. So, now ya know! Regards, and good luck.

  14. #14
    Boolit Grand Master 303Guy's Avatar
    Join Date
    Oct 2008
    Location
    New Zealand
    Posts
    9,078
    it also prevents tin-whisker formation
    Ah yes, I remember reading that. Also about reducing the electrical resistance of the joint. Very complicated! Specially for a mere mortal such as myself.

    sagacious, are you a metalurgist or metalurgical chemist or chemist something? You know way too much to be a mere mortal! You've got a broad knowledge base and a deep insight into things.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

  15. #15
    Boolit Master madsenshooter's Avatar
    Join Date
    Jan 2006
    Location
    Upper Appalachia, SE Ohio
    Posts
    3,020
    Hmm, I see. The alloys I've worked up that contain around .5% Cu are good for 2450fps, that's as far as I've gone with the Eagan MX3-30AR in my K31. This thread is interesting, I've had lots of fellows tell me how to get Cu into the melt, but generally their ideas didn't work as well as expected. Can't wait for you to get a bit more scientific 303guy. I'm getting to the age that I have a lot of tin-whiskers myself, silver helps that? Not a claim I've seen for colloidal silver yet! I could stand to have some of the electrical resistance of my joints reduced too! Just playing with words, feel free to ignore me.

  16. #16
    Boolit Master



    Join Date
    Apr 2009
    Location
    Pinehurst, NC
    Posts
    940
    Quote Originally Posted by 303Guy View Post
    It's so easy it should be illegal! After reading and talking and looking up on the 'net, i decided to try adding copper to an already pretty goold pot of alloy which is presumably lead-tin.

    I took a piece of copper I had, tinned it with soft electrical solder and submerged it into the melt. The melt has Kitty Litter on top and I fluxed with a stick, leaving a carbon rich layer close to the metal surface. The copper dissolved into the melt and that was it!

    End results - benefits or changes? Well, the casting seem harder than before and also seem to harden quicker. There is no loss of ductility. The most noticable difference is the color of the sprue plugs. Very colorful whereas before they were shiny silver. There is a slight difference in the appearance of the castings but only slight. More than that, I don't know. I'll see how the castings harden or toughen or even soften over time.
    I have read the entire thread and there is one simple sentence that I have not figured out "I took a piece of copper I had, tinned it with soft electrical solder". How does one "tin copper"?

    EW

  17. #17
    In Remembrance

    DukeInFlorida's Avatar
    Join Date
    Oct 2009
    Location
    East and South of you
    Posts
    3,566
    "Tinning" is the process of coating one metal with another. It doesn't need to be specifically tin that you coat things with. The term came from the old methods of coating steel cans with tin, making.... "tin cans".....

    The term tinning is also used in the electrical industry, where tinning copper is a way of keeping the copper from oxidizing. Marine grade wiring, for example, has a tin coating on the copper wires, so the copper doesn't turn black in the damp environment. Use marine grade wiring on boats, not un-tinned automotive grade wiring.

    Typically, in exactly the same way as you solder copper pipe fittings onto copper pipe.... you FLUX the copper (liquid flux is easiest with this smelting thing), and then apply the tinning alloy with a torch, spreading it around to coat the surface. Once the tinned copper is prepped, you can dunk it in your melt.

    Your jacketed bullets are copper (typically), so the addition of some copper in your cast alloy shouldn't hurt your bore at all.

    Quote Originally Posted by Edubya View Post
    I have read the entire thread and there is one simple sentence that I have not figured out "I took a piece of copper I had, tinned it with soft electrical solder". How does one "tin copper"?

    EW


    NRA Life Member
    NRA Certified Metallic Cartridge Reloading Instructor

    Author of a book on reloading
    ILSA MEMBER http://www.internationallawnsteelsho...ssociation.com
    NRA RANGE SAFETY OFFICER


  18. #18
    Boolit Master
    Join Date
    Oct 2009
    Posts
    1,839
    I would really be interested in a formula that would produce a mixture of copper consistently the same, without the consistency there could be accuracy and other problems. Would also be nice to know the strength/hardness of a mixture to see what direction things are going.

    303Guy, are you going to continue testing your find concerning copper ?

  19. #19
    Boolit Master



    Join Date
    Apr 2009
    Location
    Pinehurst, NC
    Posts
    940
    Thank you Duke. You cleared that up a lot better than I could have asked for.

    EW

  20. #20
    Boolit Grand Master 303Guy's Avatar
    Join Date
    Oct 2008
    Location
    New Zealand
    Posts
    9,078
    Thanks Duke, you said it way better than I could.

    I will be continuing with this copper trial thing yes. To get a consistent copper content, assuming there is no copper in the melt already (pretty coloured skin formation), it's a simple matter of weighing the pot contents, and calculating the required copper weight. It's a small amount.

    Copper is used as a bearing metal constituent (babbit) so it can only be good for the bore.

    One can add zinc in the same way or much more readily available, add brass to get both copper and zinc. Zinc hardens the lead and also makes it more brittle so not good for a hunting boolit. My idea of lead-tin-copper is for a strong and ductile hunting boolit.
    Last edited by 303Guy; 03-28-2015 at 04:10 PM.
    Rest In Peace My Son (01/06/1986 - 14/01/2014)

    ''Assume everything that moves is a human before identifying as otherwise''

Page 1 of 5 12345 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check