Adding Copper Using speaker wire.

[GregLaROCHE]

I know I read somewhere in the last six months about using speaker wire to add to alloy to toughen it up. The very fine strands allow it to melt and mix with lead at lower than normal melting temperature for copper. Does anyone else remember anything about this?

Thanks

[Hannibal]

Metals melt at particular temperatures dependent upon their composition. Size matters not.

[BK7saum]

Never done it, but I believe the wires are tinned and the tinned copper dissolves into the alloy at normal casting temps. High temps are not required.

[DougGuy]

If a 6,000+ degree flame won't melt a torch tip made out of copper, what makes you think a 700 degree lead pot will melt or dissolve it tinned or not?

[BK7saum]

First of all, your 6000+ degree flame is burning outside the tip and not transferring the heat to the tip. The melting point of copper is only 1984 degrees Fahrenheit.

Secondly, I said I've never done it. I am only reporting conflicting info to what Hannibal said. That info has been reported on CB by folks who stated they have added copper to their alloy by using tinned fine strand copper wire (speaker wire). Its not a matter of melting, but solubility.

[BK7saum]

http://castboolits.gunloads.com/showthread.php?86682-Alloying-Copper-into-Lead-Tin

[Grmps]

Some people use copper sulfate (root killer)
There are a couple threads about that.

[Hannibal]

I'd encourage skepticism regarding things read on the internet, BK7.

[BK7saum]

I'd encourage skepticism regarding things read on the internet, BK7.

Absolutely, i don't take anything at face value. I just responded in response to the OPs question where others posted it was possible and they had accomplished it. You said it was not possible or dismissed it as being possible, which prompted me to post what I did.

Then DougGuy jumped in as well with a similar statement to yours. "If a 6,000+ degree flame won't melt a torch tip made out of copper, what makes you think a 700 degree lead pot will melt or dissolve it tinned or not?"

The thread I referenced was from our own site where our members reported it was done. That was in 2010. I have come across other, similar threads, that one was at the top of the list in a search I did. You and DougGuy have been members here for 5 years. Surely, you have come across some similar threads yourself? Please go resurrect the older thread and call our members out as liars for what they stated they had done.

I haven't attempted adding Cu to. Pb/Sb/Sn alloy myself, but I dont think I'd call someone a liar, especially our own members without some testing or research of my own. What happened to the open-minded attitude that supported trying new methods of casting, coating, and shooting cast boolits?

The solubility of Cu is 0.7% in Pb. With an alloy, that could be higher or lower depending on the interaction of the elements in the alloy.

Again, I HAVE NOT added Cu to a Pb alloy by placing tinned Cu wire in my melting pot, therefore I am not saying with 100% certainty that it is doable. I was just reporting that others on this forum stated they had and it is scientifically plausible based upon the chemical properties of Cu, Pb, and Sn.

[jsizemore]

Post #4

http://castboolits.gunloads.com/showthread.php?172475-High-Copper-Alloys-Lets-discuss-this-further&highlight=speaker

You don't necessarily need to tin the wire before adding. Drop the tin in and add your copper wire in a little at a time and stir. When it's hit it's limit the wire will stop going into solution. You don't need much.

[john.k]

For the same reason copper dissolves in mercury .....at room temperature.

[Jniedbalski]

Also you can add small amounts af silver to your pot just like small amounts of copper

[Jniedbalski]

It’s like the aluminum pistons with silicone in it called hiperutetitc spelled wrong. They can only add so much silicone to the aluminum before it quits going into solution . like ice tea with to much sugar in it

[Hossfly]

What is the melting point of sb=1167’f

[Hannibal]

Absolutely, i don't take anything at face value. I just responded in response to the OPs question where others posted it was possible and they had accomplished it. You said it was not possible or dismissed it as being possible, which prompted me to post what I did.

Then DougGuy jumped in as well with a similar statement to yours. "If a 6,000+ degree flame won't melt a torch tip made out of copper, what makes you think a 700 degree lead pot will melt or dissolve it tinned or not?"

The thread I referenced was from our own site where our members reported it was done. That was in 2010. I have come across other, similar threads, that one was at the top of the list in a search I did. You and DougGuy have been members here for 5 years. Surely, you have come across some similar threads yourself? Please go resurrect the older thread and call our members out as liars for what they stated they had done.

I haven't attempted adding Cu to. Pb/Sb/Sn alloy myself, but I dont think I'd call someone a liar, especially our own members without some testing or research of my own. What happened to the open-minded attitude that supported trying new methods of casting, coating, and shooting cast boolits?

The solubility of Cu is 0.7% in Pb. With an alloy, that could be higher or lower depending on the interaction of the elements in the alloy.

Again, I HAVE NOT added Cu to a Pb alloy by placing tinned Cu wire in my melting pot, therefore I am not saying with 100% certainty that it is doable. I was just reporting that others on this forum stated they had and it is scientifically plausible based upon the chemical properties of Cu, Pb, and Sn.

I never called anyone a liar, those are YOUR words.

We could argue definitions and semantics at length, but it is not an exercise I am interested in.

The short answer is, copper can not be melted into lead alloy in a casting pot by the home casting hobbiest.

The composition of the 'copper' speaker wire and highly elevated casting pot temperatures are likely what produces the results.

No matter, I can see you are convinced. Enjoy your casting, and I apologize for any insult. I assure you none was intended.

[popper]

Normally the wire is tinned to prevent oxidation of the copper which occurs rapidly when heated.

[BK7saum]

Hannibal, apology accepted and extended back to you as well. I probably shouldn't have responded with "calling people a liar", but when they say they did and you say it can't be done, that is where I went with my response. I am not 100% convinced as I haven't done it, but I do generally respect the research and testing that is put forth by those on this site.

But by your definition, how do you "melt" lead into mercury at room temp to form an amalgam. Chemistry and elemental interaction are sometimes strange and defy normal logic.

Good luck in your casting and shooting. No offense intended as well.

Have a Happy Thanksgiving, Brad

[JonB_in_Glencoe]

From anecdotal evidence, I'd say Copper is absorbed into a boolit alloy (from copper jackets) during smelting/fluxing of range scrap. One source of Range scrap ingots that I've purchased, was tested to have 0.25% Cu.

PS: notice I used the word absorbed and NOT melted. I think the fluxing action is the driver of that absorption.

[jmort]

Hypereutectic
You cannot melt antimony in a lead alloy, in a common home melter, but it will disolve to a point, 3 to 5% as I remember it.
I do not know if copper disolves in a lead/lead alloy, like antimony.

[farmerjim]

http://castboolits.gunloads.com/archive/index.php/t-86682.html

[jsizemore]

Normally the wire is tinned to prevent oxidation of the copper which occurs rapidly when heated.

Thanks for that info. I fluxed with pine rosin after adding the wire. Between stirring and flame I cut down on the oxidation and increased the surface temp of the melt. I make my own flux for soldering electrical parts from pine rosin.

[WebMonkey]

also tinning is not alloying.

so tinning won't bring the melt temp of copper down to solder melt temp.

i'm not saying anything about speaker wire in casting lead, i'm just saying tinning isn't alloying. just helps solder stuff together.

:)

[Hamish]

The short answer is, copper can not be melted into lead alloy in a casting pot by the home casting hobbiest.

I am amazed, literally daily, at the speed at which knowledge under general discussion on this board disappears, and later, sometimes within months, is said to be impossible or never happened.

(Not directed at you Hannibal, it runs all through this thread and many others, notably the 7383 thread currently up.)

[jmort]

This is from the thread that was linked, and makes sense:

"I found out what the eutectic for lead-copper is at our temperatures - it's 0.06%. That's the solubiity of copper into lead."

[sqlbullet]

Hamish and jmort bring some great context to this dialog. I hope I can add a few items as well.

First some chemical precedence. Table salt melts at 1,474°F. However it will dissolve in plain old water at room temperature of 72° F, to a point. That point is the solubility point to which jmort refers. Generally, the higher the temperature, the higher the solubility. Likewise, sugar melts at 320° F, but will dissolve into water at room temperature. And, anyone that has made sweet tea knows that it is easier to dissolve the sugar in hot tea than in cold tea. And anyone who has made sugar rock crystals as a kid knows that you can over-saturate the water with sugar and then see it come back out of solution as the temperature drops.

So, independent of melting we have a couple of principles here:

1. A solute will dissolve in a solvent at temperatures less than the melting point of the solute.
2. Solubility is the maximum concentration of the solute in the solvent at a given temperature.
3. Full concentration of the solute can be achieved more rapidly by raising the temperature of the reaction.
4. If the solution is over-saturated for the current temperature, the solute will crystalize back out of the solution.

The melting point of copper is very high (1,984° F) and not achievable in our bullet casting pots, though it is well below the boiling point of lead (3,180° F). And partial pressure vaporization of lead would become a hazard for the operator of a lead pot at a temperature high enough to melt copper.

This leaves us with the question of solution. Can solid copper dissolve in lead. jmort has provided the needed data already. Yes, and it's solubility is 0.06%.

But, we don't actually deal with lead. We use lead/tin/antimony alloys. And it turns out that copper is more soluble in tin than it is in lead. Close to 10% copper will dissolve in tin at 700° F.

It also turns out that "tinning" a copper wire with pure tin solder will result in an intermetallic boundary composition where right at the boundary between the two the copper dissolves into the tin. It is a significant problem in modern integrated circuits that the technology world is trying to solve. But for us, this is a win as this intermetallic alloy does have a lower melting point than copper. I could not easily find any information about the constituent percentages of the intermetallic tin/copper compound, and so I cannot estimate the melting point of the compound. I would guess it is still higher than our pot temp, and the percentage of copper involved in the intermetallic layer is very, very small, so this is a small win that doesn't really buy us much.

So, now we know the following items as well:

1. Copper will dissolve in lead, but not at a high enough solubility to get us much result.
2. Copper will dissolve in tin at a much higher rate.
3. Tinning copper with pure tin solder results in a fully saturated boundary.
4. The boundary is so thin as to not net us enough solubility boost to matter much.

So, with this information, on to practical usage of this knowledge.

I started out with copper filings in the pot of lead. Just as granulated sugar or salt will dissolve more quickly than a large crystal due to surface area, copper filings offer far more surface area. I had several problems with this method: I am not a patient man. I am an irrational cheapskate who couldn't just walk away from a burning propane. I had to stay anyway to regulate the melt temp so as not to oxidize off more than I was gaining.

So, copper filings were a bust for me.

I didn't try copper sulfate. I didn't have any and I did have lots of copper wire around from a remodel.

I tried tinning wire and putting it in the pot. I carefully cleaned the wire with steel wool and immediately tinned it with pure tin solder. This went into the pot but the same basic challenges I had with copper filings came up.

So, I checked a binary phase chart for copper-tin and gained hope. Pure tin melts at a reasonably achievable temperature. And pure tin should dissolve a fair bit of copper pretty easily. And, I really didn't need that much, as I just wanted to get to about .25-.5% copper in my final lead/antimony/tin/copper alloy. That is 4-8 ounces of copper in a 100 lb dutch oven of lead alloy.

Well, copper may have a much higher solubility in tin than in lead, but it is not enough higher to offset my impatience. On to plan four.

I set up my 4 lb steel ladle and grabbed my MAP torch and set about melting 5 oz of copper. That worked. Then I started adding tin bar solder. Luckily I have a fair bit from some trading I did seven or eight years back. The goal here was to dilute the copper down to a solution in the tin, then add that mixure to a pot of lead I already had melted. But, that was going to require over 3 lbs of tin, which was a higher tin level than I really wanted in my final alloy. I finally decided to just do it. I had tin laying around.

So, 50 ounces of tin were added to my 5 ounces of copper, for a final solution of 9% copper, 91% tin. This remained liquid down to about 650° and so could be added to a 700° pot. 1 lb ingots were cast, and I still have those floating around. I ended up with 87 lbs of ingots from that pot, which works out to 0.35% copper, 2.88% antimony, 4.55% tin and 92.22% lead. My plan was to use these about 3:1 with my standard isotope lead.

But, since I created this alloy several years back, I have been busy with a home remodel, wedding and garage build, and shooting has taken a back-seat to these other priorities.

To the OP...Speaker wire would have an advantage of more surface area to volume and so would dissolve more quickly relative to a 12 or 14 gauge solid wire. Also, if frayed and tinned individually, a greater percentage of intermetallic compound would form. Though I don't think it will melt at pot temp, it should dissolve more quickly in your melt than pure copper. Tinning the wire without fraying would probably offset the surface area to volume benefit of a solid wire. Stranded wire would still be better than solid, but not as good as frayed strands.

I have largely ignored oxidation in this post, but it is very relevant. Copper oxide will prevent the copper from dissolving, and I bypassed this by melting the copper in my method.

Hamish, I don't know if I have added any knowledge to this thread or not. But I hope I have.

Edit: Citations!

https://www.ncbi.nlm.nih.gov/books/NBK431100/
https://www.researchgate.net/profile/Charlie_Sanabria/publication/316317422/figure/fig16/AS:485605726527492@1492788835522/The-Cu-Sn-phase-diagram-This-phase-diagram-will-be-very-relevant-for-the-rest-of-this.png
https://en.wikipedia.org/wiki/Copper
https://en.wikipedia.org/wiki/Intermetallic
https://www.tandfonline.com/doi/abs/10.1080/00202967.1983.11870635?journalCode=ytim20 (paywall, but the abstract is here.)
https://www.sciencedirect.com/science/article/abs/pii/S135964540100146X (paywall, but the abstract is here.)

[Hossfly]

Very good experiment, and explains the total experience. Thanks for that. Been following this since it started. I’m relatively new at casting and find all aspects of it very interesting.

[Mr_Sheesh]

Hamish, lots of peoples' brains are Swiss Cheese-y - My excuse is that it's my "Old-Timers" LOL - All of us can remember some things and not others. We're not computers, and that is a GOOD thing :)

[Hamish]

sqlbullet,

Bravo sir, outstanding post!

0.25-0.5% Cu equals "sweet spot". More is not better.

[Hamish]

Hamish, lots of peoples' brains are Swiss Cheese-y - My excuse is that it's my "Old-Timers" LOL - All of us can remember some things and not others. We're not computers, and that is a GOOD thing :)

Too many state an opinion without talking a minute to do a search.......

[BNE]

Hamish and jmort bring some great context to this dialog. I hope I can add a few items as well.

First some chemical precedence. Table salt melts at 1,474°F. However it will dissolve in plain old water at room temperature of 72° F, to a point. That point is the solubility point to which jmort refers. Generally, the higher the temperature, the higher the solubility. Likewise, sugar melts at 320° F, but will dissolve into water at room temperature. And, anyone that has made sweet tea knows that it is easier to dissolve the sugar in hot tea than in cold tea. And anyone who has made sugar rock crystals as a kid knows that you can over-saturate the water with sugar and then see it come back out of solution as the temperature drops.

So, independent of melting we have a couple of principles here:

1. A solute will dissolve in a solvent at temperatures less than the melting point of the solute.
2. Solubility is the maximum concentration of the solute in the solvent at a given temperature.
3. Full concentration of the solute can be achieved more rapidly by raising the temperature of the reaction.
4. If the solution is over-saturated for the current temperature, the solute will crystalize back out of the solution.

The melting point of copper is very high (1,984° F) and not achievable in our bullet casting pots, though it is well below the boiling point of lead (3,180° F). And partial pressure vaporization of lead would become a hazard for the operator of a lead pot at a temperature high enough to melt copper.

This leaves us with the question of solution. Can solid copper dissolve in lead. jmort has provided the needed data already. Yes, and it's solubility is 0.06%.

But, we don't actually deal with lead. We use lead/tin/antimony alloys. And it turns out that copper is more soluble in tin than it is in lead. Close to 10% copper will dissolve in tin at 700° F.

It also turns out that "tinning" a copper wire with pure tin solder will result in an intermetallic boundary composition where right at the boundary between the two the copper dissolves into the tin. It is a significant problem in modern integrated circuits that the technology world is trying to solve. But for us, this is a win as this intermetallic alloy does have a lower melting point than copper. I could not easily find any information about the constituent percentages of the intermetallic tin/copper compound, and so I cannot estimate the melting point of the compound. I would guess it is still higher than our pot temp, and the percentage of copper involved in the intermetallic layer is very, very small, so this is a small win that doesn't really buy us much.

So, now we know the following items as well:

1. Copper will dissolve in lead, but not at a high enough solubility to get us much result.
2. Copper will dissolve in tin at a much higher rate.
3. Tinning copper with pure tin solder results in a fully saturated boundary.
4. The boundary is so thin as to not net us enough solubility boost to matter much.

So, with this information, on to practical usage of this knowledge.

I started out with copper filings in the pot of lead. Just as granulated sugar or salt will dissolve more quickly than a large crystal due to surface area, copper filings offer far more surface area. I had several problems with this method: I am not a patient man. I am an irrational cheapskate who couldn't just walk away from a burning propane. I had to stay anyway to regulate the melt temp so as not to oxidize off more than I was gaining.

So, copper filings were a bust for me.

I didn't try copper sulfate. I didn't have any and I did have lots of copper wire around from a remodel.

I tried tinning wire and putting it in the pot. I carefully cleaned the wire with steel wool and immediately tinned it with pure tin solder. This went into the pot but the same basic challenges I had with copper filings came up.

So, I checked a binary phase chart for copper-tin and gained hope. Pure tin melts at a reasonably achievable temperature. And pure tin should dissolve a fair bit of copper pretty easily. And, I really didn't need that much, as I just wanted to get to about .25-.5% copper in my final lead/antimony/tin/copper alloy. That is 4-8 ounces of copper in a 100 lb dutch oven of lead alloy.

Well, copper may have a much higher solubility in tin than in lead, but it is not enough higher to offset my impatience. On to plan four.

I set up my 4 lb steel ladle and grabbed my MAP torch and set about melting 5 oz of copper. That worked. Then I started adding tin bar solder. Luckily I have a fair bit from some trading I did seven or eight years back. The goal here was to dilute the copper down to a solution in the tin, then add that mixure to a pot of lead I already had melted. But, that was going to require over 3 lbs of tin, which was a higher tin level than I really wanted in my final alloy. I finally decided to just do it. I had tin laying around.

So, 50 ounces of tin were added to my 5 ounces of copper, for a final solution of 9% copper, 91% tin. This remained liquid down to about 650° and so could be added to a 700° pot. 1 lb ingots were cast, and I still have those floating around. I ended up with 87 lbs of ingots from that pot, which works out to 0.35% copper, 2.88% antimony, 4.55% tin and 92.22% lead. My plan was to use these about 3:1 with my standard isotope lead.

But, since I created this alloy several years back, I have been busy with a home remodel, wedding and garage build, and shooting has taken a back-seat to these other priorities.

To the OP...Speaker wire would have an advantage of more surface area to volume and so would dissolve more quickly relative to a 12 or 14 gauge solid wire. Also, if frayed and tinned individually, a greater percentage of intermetallic compound would form. Though I don't think it will melt at pot temp, it should dissolve more quickly in your melt than pure copper. Tinning the wire without fraying would probably offset the surface area to volume benefit of a solid wire. Stranded wire would still be better than solid, but not as good as frayed strands.

I have largely ignored oxidation in this post, but it is very relevant. Copper oxide will prevent the copper from dissolving, and I bypassed this by melting the copper in my method.

Hamish, I don't know if I have added any knowledge to this thread or not. But I hope I have.

Edit: Citations!

https://www.ncbi.nlm.nih.gov/books/NBK431100/
https://www.researchgate.net/profile/Charlie_Sanabria/publication/316317422/figure/fig16/AS:485605726527492@1492788835522/The-Cu-Sn-phase-diagram-This-phase-diagram-will-be-very-relevant-for-the-rest-of-this.png
https://en.wikipedia.org/wiki/Copper
https://en.wikipedia.org/wiki/Intermetallic
https://www.tandfonline.com/doi/abs/10.1080/00202967.1983.11870635?journalCode=ytim20 (paywall, but the abstract is here.)
https://www.sciencedirect.com/science/article/abs/pii/S135964540100146X (paywall, but the abstract is here.)


BRAVO Sir. Best answer and explanation. There is a huge difference between melting and alloying. You described it well. Thank you. I hope some of the original nay sayers come back and read your post.
BNE.

[dimaprok]

If a 6,000+ degree flame won't melt a torch tip made out of copper, what makes you think a 700 degree lead pot will melt or dissolve it tinned or not?

I've done it, I melted about 2.85oz of copper wire (80 grams) in to tin making it about 10% copper alloy per my calculations based on weight.

When I read original post the author used the acid flux for soldering pipes but I didn't have any so I decided to use rosin puck I had for 20 years that my friend gave me, I knew I would never use it my lifetime so might as well put it to good use and it worked!

So I discovered as others wrote is multi stranded wire by itself dipped in to tin would not melt but when dipped it in tin to heat it up and dipped in to rosin it would melt pretty quick, I also used candle wax to keep tin oxidation down. I also melted couple copper pennies but it was very hard to do and took long time. I was using propane coleman camping stove and it was messy as rosin splatters and smokes. In the end when I made little puddles of tin it had bronze color to it compare to normal tin. Bronze IS tin and copper after all :) just in opposite ratio with high percentage of copper.

[jmort]

I predict you have a hot mess on a molecular/alloy level. Would love to see a few XRF results to see. Even then, only an electron microscope would reveal the alloy matrix. I hope you found what you are looking for.

[10 ga]

after reading all this my old head hurts. I'm thinking my 1 - 1 - 1 + 2% is pretty good. That's range scrap - COWW - soft + 2%tin !!! 10

[popper]

Solubility of Cu in Pb is 0.03% at room temp. Cu fills empty crystal lattice spaces in the Pb and does increase 'hardness' an malleability. The Sb/Cu molecules fill the lattice void. I have gone to 2% Cu in a Sb/Pb mix, hard as superhard. Cu alloys with Sb, so Sb MUST be 2x the Cu%. 12%Sb/6%Cu works (limit of strengthening) but hey who needs that? Adding Cu to high Sb alloy prevents the boolit from being brittle. Rosin & acid flux is used to remove oxidation from copper wire and reduce surface tension of tin further so the tinning 'bonds' and yes it is a thin layer. Semiconductor industry has some really exotic 'solders' to eliminate tin, copper, gold migration problems. NASA invented 'non-weldium alloys that would not 'weld' at 0 deg. Kelvin in a vacuum. Couldn't disconnect the wiring in returning space craft.

[Lloyd Smale]

when smelters alloy metals they use fluxes especially formulated to mix them and temps high enough to do it. If you take some copper wire and got it hot enough to melt over your pot the second it hits the 700 degree lead its going to act just like you dropped it in water. I doubt you will get anything more then blobs of copper in your lead. You need to find babbit that has already had copper added.

[jmort]

@sqlbullet
Very interesting. You have to consider the alloy.
Interesting thread.

[Tom W.]

When I could get Ni Babbitt It had no lead but did have some copper in it. It was mostly tin, and made some hard boolits if used by itself. I had some scraps of Silver solder left over from putting carbide teeth onto saws so I saved a few pieces and took them home to add to my lead pot to see what would happen.

Nothing.
They just floated around.

Maybe if I had added them to my dutch oven and tried melting them with COWW they may have blended, but I'll never know.....

[dimaprok]

when smelters alloy metals they use fluxes especially formulated to mix them and temps high enough to do it. If you take some copper wire and got it hot enough to melt over your pot the second it hits the 700 degree lead its going to act just like you dropped it in water. I doubt you will get anything more then blobs of copper in your lead. You need to find babbit that has already had copper added.

Didn't you read anything that was written in this thread??? A) People have done it including me and no copper didn't float like blob it got dissolved like a salt dissolves in the water even though salt has something like 1300 melting point. If you're not going to read the whole thread than at least read what SQLbullet wrote.

[beagle]

Probably the easiest way to add copper to your alloy is to find some copper rich Babbitt alloy. This will melt into the mix. Felix and I did some tinkering with this way back and it works. Normally one Babbitt bar to a pot does the trick. The problem is the alloy content is very hard to repeat and it's a hit or miss thing. We were messing with .223s so once a pot of alloy was established, we made a whole pot of .22 bullets./beagle