Solder Hardness

I had about 200 lbs of solder I salvaged at work (before I retired) that they were going to pay a hazardous waste company to haul away. Out of the goodness of my heart, I offered to dispose of it at no charge. This stuff was originally 40/60 Sn/Pb, I think. It was cast into various configurations, mostly triangular from angle iron, depending on what they could find to pour it into. In order to make it more compact for storage, I melted it down and cast it in small ingots (Lyman, RCBS, etc.). Since this stuff sat in a large solder pot in the molten state for hours at a time, I'm not sure what the Sn/Pb proportion is now.

I have tested 4 sample ingots with the Cabine Tree tester. Two of the ingots were cast in a Lyman aluminum mold and two were cast in a SAECO iron mold. Averages of 4 readings each were as follows:

Cabine Tree Brinell

#1 Lyman .089 22

#2 Lyman .087 22 * .080 lowest reading

#3 SAECO .090 22

#4 SAECO .089 22

Except for the noted low reading above the ES of all readings was .005 and the high and low were on different samples.

I'm not sure whether I'm using poor technique or whether the alloy is not really solder. I don't see how a tin/lead alloy could be that hard. I am sure there is no Pb in the alloy. I have tested some of my WW ingots and the readings were within the range Gussie gives with the cross reference chart he includes with the tester.

Does anyone have any ideas???

Sorry about running everything together, I can't seem to maintain any spacing.

John

The of 60/40 solder should have a maximum BHN of17. Could it have some antimony in it? Could they have thrown some WW into the mix? Whatever the contents are it sounds like you have some good alloying material for WW or pure lead. In my experience Gussy's tester is first rate. You said there was no Pb in the alloy but state it is 60/40 Sn/Pb solder, was that a typo?

Quote:

---

Originally Posted by USARO4

The of 60/40 solder should have a maximum BHN of17. Could it have some antimony in it? Could they have thrown some WW into the mix? Whatever the contents are it sounds like you have some good alloying material for WW or pure lead. In my experience Gussy's tester is first rate. You said there was no Pb in the alloy but state it is 60/40 Sn/Pb solder, was that a typo?

---

I meant Sb (antimony). Not a typo. Just a hiccup in my thought process. The company was very particular in specifying materials. This was used in fabricating components for power transformers and I was the manufacturing engineer in the area that used the solder. There is no possibility of anything other than tin and lead since the pot was replenished with roll (25#) solder. I have a lot of that also. I won't be making ingots out of that. I don't want any possibility of not knowing what it is.

One thing I noticed when dumping the ingots from the molds, some of the ingots would break and leave a granular looking edge. I assumed it was because I tried to hurry the cooling process and they were still too hot. All were poured at about 470 to 500 degrees.

One caution that needs to be mentioned. As I was finishing feeding in the last of the various bars there was a wad of what I thought was solid solder. When I threw it into the pot (40# pot on a plumbers furnace) I saw at once it was rosin core solder. What a mess! That stuff smokes forever and coats the pot and ladle.

John

Isn't there some "lead-free" solder that is just tin and antimony? with that hardness level, it may be the tin/antimony solder...

Quote:

---

Originally Posted by MakeMineA10mm

Isn't there some "lead-free" solder that is just tin and antimony? with that hardness level, it may be the tin/antimony solder...

---

I am just short of 100% certain that this stuff has NO antimony. I just tested some ingots that I poured up several years ago that has to be nearly the same solder alloy (40/60) and it gives a dial reading in the .068 to .072 range which translates to 10 to 11.5 range, which is what I would expect. I'm wondering if it will soften over the next several days to weeks. I will try it again next week.

Does it really matter?

Whatever it is is what you've got, and you've got a lot of it. Treat it like 50/50 and see how the bullets come out. At worst, you'll be using a little more tin than you really need to.

Since WW is mystery metal anyway, and it's what most of us use as a base, fretting about exact percentages is bootless.

Quote:

---

Originally Posted by Leftoverdj

Does it really matter?

Whatever it is is what you've got, and you've got a lot of it. Treat it like 50/50 and see how the bullets come out. At worst, you'll be using a little more tin than you really need to.

Since WW is mystery metal anyway, and it's what most of us use as a base, fretting about exact percentages is bootless.

---

You're right. It really doesn't matter. I just ran into something I didn't understand and wondered if anyone had any ideas. For those applications where the ratio of Tin to Lead is important, I will use the roll solder. It is plainly marked as 40/60. Unless I decide to start casting solder boolets I won't have to worry about using a little more than is needed. For adding to WW, I'll just add what is needed to get good fill.

Quote:

---

Originally Posted by MakeMineA10mm

Isn't there some "lead-free" solder that is just tin and antimony?

---

It was being used to fabricate electronic components. That pretty much guarantees it is not one of the lead free mixes. 60/40 (or 63/37) is still (last I heard) the preferred solder for that industry.
CM

Lead mixed with other metals seems to get harder over time. If you want to for giggles, remelt a couple ingots and check them again for hardness afterward!

A minor point: 60/40 solder is 60% tin, not 60% lead.

Quote:

---

Originally Posted by grumpy one

A minor point: 60/40 solder is 60% tin, not 60% lead.

---

Not really that minor. Mine is 40/60. In other words, 40% Tin, 60% Lead. I have tried to be consistant when typing what I have. I am well aware that the Tin percentage comes first. I believe the 63/37 mentioned by Montana Charlie is eutectic solder. Goes directly from solid to liquid. I'm not a metallurgist, but I know what I have is not eutectic. That stuff is used in electronics. Our use was in power transformers, as in huge equipment.

There's no reason solder can't be made out of any proportions of tin and lead, and what you have can be determined by measuring the melting point. I agree, you have been consistent in saying that what you have is 40% tin. I don't recall ever encountering that mixture, but it could have applications of course. For example the radiator industry used multiple alloys because of their different melting points: the fins were soldered to the tubes in the factory using low tin solder, so that the repair industry could use eutectic solder for repairs, without any danger of melting the structural joints in the radiator (provided they were careful with the torch, of course.)

I don't know for sure, but I suspect that 40/60 solder was specified many years ago because it worked for the application and was cheaper. I worked for Westinghouse and for the successor company until retirement. Our application was to sweat threaded joints on electrical connectors. These joined copper or brass from approx. 1" diameter to 12" or greater. Some of these joined items conducted current from 400 amps to 20,000 amps or sometimes greater. These were considered low voltage devices at about 25kV. All this was "old" technology. I'm not an electrical engineer. I just made sure the specs were followed.

I'm going to back out of this thread since it has somewhat taken a turn away from cast boolets. Mostly because of me and my wandering mind. Appreciate all the replies and, as I said, Iwill test the hardness of the ingots again in a week or two. Whatever the result, as Leftoverdj suggested, it will be headed for the WW pot.