Unkown solder melt experiment

[zomby woof]

I bought a bunch of bulk solder. I'm trying to figure what ratio of tin/lead there is in all these different pieces. I came up with an experiment but did not get the results I expected. I had known 63/37, 95/5 and 50/50. The 63/37 melted first (it had flux in it), then the 50/50. The 95/5 melted last, I'm guessing the 5% antimony made it melt later. I was thinking the 95/5 would melt first because of the high tin percentage. Most of the solder I tested melted along with the 95/5. However, it doesn't look as silver as the known 95/5. I got frustrated and figured I'd just cut it up into 2 ounce pieces and toss it in my pot.

[ANeat]

Here I tried to copy paste this chart, 63/37 is the eutetic blend that will have a definite solid to liquid temp. And the lowest melting temp. The others will go thru a slush stage before getting to the actual melting temp

Also your solder is probably tin/lead, not antimony as you mentioned

Blend ----- Melting temp
Sn63Pb37 361
Sn60Pb40 361-374
Sn55Pb45 361-397
Sn50Pb50 361-420
Sn45Pb55 361-440
Sn40Pb60 361-460
Sn35Pb65 361-477
Sn25Pb75 361-514
Sn20Pb80 361-536
Sn10Pb90 514-576
Sn05Pb95 574-597

[AJ Peacock]

I've done essentially the same kind of experiments. If I was using bulk solder that was unknown, I'd melt it all together, stir it up and pour it into the corner of a piece of angle iron (essentially make my own bar solder). Then I'd cut a chunk of it and weigh it in and out of water to get it's specific gravity. From there you can easily determine the % Tin and %lead. I'd try to sort any 95/5 out by other means.

The density of your unknown solder mix will be given by it's weight in air divided by it's weight in water.

Lead has a density of 11.35
Tin has a density of 7.31

You can figure the % of lead/tin by looking at the following table I generated using a spreadsheet.

%LEAD --- Density --- %Tin
100% --- 11.35 --- 0%
98% --- 11.27 --- 2%
96% --- 11.19 --- 4%
94% --- 11.11 --- 6%
92% --- 11.03 --- 8%
90% --- 10.95 --- 10%
88% --- 10.87 --- 12%
86% --- 10.78 --- 14%
84% --- 10.7 --- 16%
82% --- 10.62 --- 18%
80% --- 10.54 --- 20%
78% --- 10.46 --- 22%
76% --- 10.38 --- 24%
74% --- 10.3 --- 26%
72% --- 10.22 --- 28%
70% --- 10.14 --- 30%
68% --- 10.06 --- 32%
66% --- 9.98 --- 34%
64% --- 9.9 --- 36%
62% --- 9.81 --- 38%
60% --- 9.73 --- 40%
58% --- 9.65 --- 42%
56% --- 9.57 --- 44%
54% --- 9.49 --- 46%
52% --- 9.41 --- 48%
50% --- 9.33 --- 50%
48% --- 9.25 --- 52%
46% --- 9.17 --- 54%
44% --- 9.09 --- 56%
42% --- 9.01 --- 58%
40% --- 8.93 --- 60%
38% --- 8.85 --- 62%
36% --- 8.76 --- 64%
34% --- 8.68 --- 66%
32% --- 8.6 --- 68%
30% --- 8.52 --- 70%
28% --- 8.44 --- 72%
26% --- 8.36 --- 74%
24% --- 8.28 --- 76%
22% --- 8.2 --- 78%
20% --- 8.12 --- 80%
18% --- 8.04 --- 82%
16% --- 7.96 --- 84%
14% --- 7.88 --- 86%
12% --- 7.79 --- 88%
10% --- 7.71 --- 90%
8% --- 7.63 --- 92%
6% --- 7.55 --- 94%
4% --- 7.47 --- 96%
2% --- 7.39 --- 98%
0% --- 7.31 --- 100%

Hope this helps,
AJ

[Alchemist]

AJ,

AWESOME!! Now I have a question for you.....is weighing a sample in a container of water, then subtracting the weight of the container + water, then weighing the sample alone the proper technique? I guess it should be obvious, but once in a while I have trouble getting my head around simple concepts. :veryconfu

TIA