Kester solder question

[geargnasher]

I traded for 48 bars of old Kester bar solder a few months ago, the box was destroyed and there are no marks on the bars indicating composition, I was wondering if anyone had an educated guess as to what it is. The bars are the cast, flat strip type (not triangular), have "A.S.T.M Class A" and "KESTER" moulded on the botttom side, weigh 1lb 3oz. each, and seem to have an SG of around 9.06 g/mL using a postage scale, 200 mL of water and a Chinese Pyrex measuring cup. My Lee tester scope measures a .081" dimple, which is just off their chart but I figure is around 7 BHN or so. I figured 50/50 at about 8.8 g/mLand 63-37 at about 8.5 g/mL, so I'm guessing it's 50/50 or 45/55. Any ideas?

I traded for it thinking it was pure lead, but I cut the bars in half tonight with my bolt cutters so it would fit in a smaller box and noticed it "cried" slightly like tin does when it's cut and decided to try to find out what it really is. If it has any tin in it I'm way ahead on the deal.

Gear

[shotman]

Most all was 50/50 . See if the bar will bend if so its 50/50 if it breaks it is most likely 60%tin and 40% lead That was used on sheet roofing It will melt faster

[utk]

I had exactly the same question about some solder I got. Read this thread:

http://www.castboolits.gunloads.com/...&highlight=tin

Quoting Southpaw:

"To find the percentage of tin that you have use the following formula.

2049.06 / SG - 180.69= % tin

Of course this only works if there are only PB and SN in the mix."

End quote

SG = unknown alloy's specific gravity

With your SG of 9.06 inserted into the formula it gives a tin content of 45.48%

[cbrick]

Gear, see what temp it melts at. The higher the Sn% the lower the melt temp. 60/40 solder should melt at 361 degrees.

Rick

[bumpo628]

Gear, see what temp it melts at. The higher the Sn% the lower the melt temp. 60/40 solder should melt at 361 degrees.

Rick

Not quite. According to the info in one of the stickys in this forum, it goes up and down depending on composition.

621° = lead (metal)
563° = solder (9 parts wt. lead & 1 part wt. tin) (metal)
529° = solder (8 parts wt. lead & 2 parts wt. tin) (metal)
504° = solder (7 parts wt. lead & 3 parts wt. tin) (metal)
464° = solder (6 parts wt. lead & 4 parts wt. tin) (metal)
428° = solder (5 parts wt. lead & 5 parts wt. tin) (metal)
374° = solder (4 parts wt. lead & 6 parts wt. tin) (metal)
365° = solder (3 parts wt. lead & 7 parts wt. tin) (metal)
392° = solder (2 parts wt. lead & 8 parts wt. tin) (metal)
421° = solder (1 part wt. lead & 9 parts wt. tin) (metal)
450° = tin (metal)

[cbrick]

Dunno about a sticky but I listed the composition . . . 60/40.

According to all the metals industry stuff I've read 60/40 melts at 361 degrees. With the exception of a few specialty solders for the electronics industry 60/40 is one of the lowest melting temps of "common" tin/lead solders.

63% tin and 37% lead (commonly known as 60/40 solder). Tin lowers the melting point of lead alloys, eutectic 60/40 solder melts at 361 F.

The above came frpm here:

Cast Bullet Alloys and Alloy Maintenance (pdf)

Rick

[AggieEE]

I have to put my .02 in here. I teach soldering at a local community college and 60/40 and 63/37 are two different animals. 60/40 starts to melt at 361F ( as do most of the tin lead alloys) and is liquid at 420F in between its kind of mush. 63/37, also called eutectic ( spell?) melts at 361F and is liquid at 361F plus a small fraction. In electronics, at least before all of the RoHS rules, 60/40 and 63/37 were about the only solder you saw, with 60/40 being the most common. If you have a fairly accurate thermometer check the temp at which a good size blob goes from liquid to semi solid. The melting point and the freezing point are the same. If you can melt about a 1/2 pound to give the thermometer time to react you will see the temp come down and then stop moving for a little while while it is getting solid. Then compare to the chart bumpo628 put up.
AggieEE

[geargnasher]

Thanks for the replies, all. 60/40 and 63/37 are two completely different animals. Within the ranges of 19/81 and 2.5/97.5 (including 60/40 to 40/60 in the middle range), all are solid at 361F, it's the slush window that's different. 40/60 doesn't reach full liquidus until 460F, 50/50 is 420F, and 60/40 is fully liquid at 375F, only 15 degrees above the freeze point. 63/37 is, of course, eutectic at 361F. I got all these numbers from the technical tables at J.W. Harris Co. Looks like I need to empty my casting pot and melt this stuff down to do some analysis and re-ingoting since I do have several known good thermometers. I don't know why, but I had it in my head that the solidus/slush/liquidus window between this range of binary solder compositions was much tighter than it is, so I threw out determining exactness by temperature alone without thinking it through.

I'll post results as soon as I get them!

Gear

[geargnasher]

Allright, figger this one out. I checked my thermometers tonight with some certified 99.97% pure lead, and then melted down the Kester bars.

I got full liquidus at 518, anything below it causing a SUDDEN slush that was the consistency of a half-melted and stirred-up milkshake, cooling to 490 it would shave like scooping orange sherbet with a spoon, by 480-460 it was like brown sugar, more like really dried-out brown sugar by 440, and finally got solid somewhere between 425 and 420.

So what alloy, made by Kester, has an SG of around 9, a liquidus of 518 and a solidus of around 420, and a BHN of around 7-7.5?

Gear

[lylejb]

looking on grainger's web site, they list a Lenox 50/50 bar solder at 430 melting point.

50/50 = 50/50, I don't think it matters who made it

I'd call it 50/50 and be happy, especially if you got it for lead prices.

[btroj]

I hate to ask this but I will anyway.

Does it matter a whole lot unless you are trying to mix a precise alloy? If I add some of my body solder to an alloy I don't worry too much about whether I end up with 1.4 or 1.5% Sn. I can't say that I would every know the difference.

Not trying to be a jerk, just wondering if you are doing ALOT of work for not much return. Face it Gear, I am lazy at this casting thing. Cast, load, shoot. That is my motto.

Brad

[montana_charlie]

So what alloy, made by Kester, has an SG of around 9, a liquidus of 518 and a solidus of around 420, and a BHN of around 7-7.5?

A .081" dimple made with Lee hardness tester indicates a BHN of 7.6. Would you like to have a chart that goes all the way down to 'pure lead'? I can email you one.

I have never seen any, but there is such a thing as 75/25 lead/tin solder. It's been used in vapor packaging operations.
Kester may even make some.
It's melting point should be very close to 518°.

CM

[geargnasher]

MC, an extension chart would be greatly appreciated, I should have my email link turned on to the general membership, if that doesn't work let me know and I'll pm my email.

I'm figuring by the solidus and liquidus temps it's greater than 15% Sn and less than 19%, in fact should be right in the middle. Problem is, that alloy has a density closer to about 10.7 g/mL. Binary lead/tin alloys having the density of the one I'm testing fall right around 50/50 give or take (my scales and measuring cup are only ballpark), but 50/50 begins melting at 361F and is mushy until 420, unlike what I have which is solid at 420 and liquid at 518.

Looking at solder charts for the last couple of hours has convinced me something's rotten here with my tests, or this stuff is ternary or worse.

Gear

[bumpo628]

Have you tried figuring out the mystery metal by weight & density?
I would weigh it and figure out the volume, then calculate the density.
Compare that to the weight of a similarly sized bar of pure lead and pure tin. Change the percentages until you have a match.

[montana_charlie]

MC, an extension chart would be greatly appreciated, I should have my email link turned on to the general membership, if that doesn't work let me know and I'll pm my email.

Only your through-the-forum email path is displayed, and that feature doesn't allow attachments.

Let's see if this works ... if it works, anybody can have a copy.

You should see a file attached to this post. I have several different charts, but this one is small enough to work within forum requirements. Click on it to make it bigger before copying it.
CM

[geargnasher]

Thanks CM, I sure appreciate that. Didn't realize attachments couldn't be sent through the site link, I don't use email much at all.

Bump, I did several SG determinations, but didn't have a small enough sample to use a graduated cylinder, had to use kitchen-precision measuring tools which may be throwing a monkey wrench in the works, it doesn't take much error to throw the numbers way off. I determined many SG numbers (dross composition analysis and evaluation of boolit-sized samples) in the past using a lab-grade grade graduated cylinder and my reloading scale, I think I need to cast a few boolits with this stuff and see what it is.

One of the reasons I keep after this is that there is so much variance in published values for solder alloys that I'd like to get to the bottom of it, and have a good method for folks to quickly and accurately determine the composition of scrap solder or unmarked garage sale finds, etc. The most confusing part is the vast discrepancy in published BHN values for solder.

Gear

[Astocks2622]

I know this is a super dead thread, but I'm trying to find a copy of Montana Charlie's Lee tester extension sheet for bhn below 8.0. she's anyone have a copy lying around?

Sent from my SM-G970U1 using Tapatalk

[JonB_in_Glencoe]

I know this is a super dead thread, but I'm trying to find a copy of Montana Charlie's Lee tester extension sheet for bhn below 8.0. she's anyone have a copy lying around?

Sent from my SM-G970U1 using Tapatalk

Astocks,
Welcome to the forum.
there is a link in 3rd post of this thread
https://castboolits.gunloads.com/sho...ding-pure-lead