Beginning jeweler here.
I just found out denatured alcohol is no longer available in Calfiornia. What can I use as a substitute to make boric acid flux and to use as lamp fuel for working with. Everclear is also not available here either.
Thank you in advance.
Be careful with your boron compounds. Boric acid is not a flux, it is a resist. Borax, which is not boric acid, is a flux.
Boric acid in alcohol is used to coat diamonds, so they won’t burn, and polished surfaces, so they won’t lose their polish, when going into the fire. But the boric acid must be cleared from the joint and a flux applied so the solder will flow and adhere to the surfaces of the joint.
Regarding boric acid resist, any alcohol will do. Methanol should still be available.
Boric acid is not a resist. It aids in soldering.
Boric acid is a flux. It is sometimes called a barrier flux.
Boric acid is not very soluble in water but both boric acid and borax become more soluble in water when mixed together.
Boric acid is used as a casting flux when casting Argentium sterling silver alloy.
Boric acid is soluble in alcohol, it is most soluble in methyl alcohol. Methyl alcohol is available in most places but it is strangely unevenly available. By the way an old name for it is wood alcohol. You can usually find it available where you would also find other solvents in a hardware store. Sometimes you will find it used with fiberglass work. Methyl hydrate is used to denature ethyl alcohol. It is poisonous to a degree but is often thought of as horribly poisonous and some people will be unreasonable about how poisonous it is. Use it safely and with good workmanship knowledge. Please research it on websites that are quality sites.
I welcome any question with regard to boric acid and using it as a barrier flux as I am well acquainted with it.
I am in CA too and found this out last week. I was able to order a gallon from amazon and it was delivered with free shipping with prime.
Franz
See, here’s where different shop practices get confusing. I was taught by the jewelers who trained me that after burning off the alcohol one must clear the boric acid powder from the joint and apply a flux, we always used Battern’s, or the boric acid glass would impede the flow of the solder.
Also, when melting gold scrap we’d sprinkle borax on the melt to clear impurities, never boric acid. But we only worked in gold and platinum in the shop where I trained so I’ve no experience with Argentium or any of the newer silver alloys.
Borax is sometimes confused with boric acid. Both borax and boric acid are known as borates, which are compounds that come from the element boron. In all actuality, there wouldn’t be any boric acid without borox.
Borax and boric acid are both naturally occurring compounds that are found in arid regions like the salt plains in Utah or Nevada. Borax, or Sodium Tetraborate (Na2B4O7 • 10H2O), is made up of sodium, oxygen and boron. Boric acid is created from the mixture of borax with other naturally occurring minerals such as boracite and colemanite. Basically, the addition of hydrogen or another acid to borax creates the compound boric acid or hydrogen borate (H3BO3).
No need to remove the boric acid. It is a flux. And we use Borax on all of our metal castings except for platinum casting.
Attached find a paper presented at theSanta Fe Symposium on soldering by Ann Cahoon. Even though I’ve been making jewelry for 51 years I always bow to her superior knowledge. Introduction. All SFS papers are available online for free.
Well heck! The tables didn’t show when I copied this but you can find them online at Papers — The Santa Fe Symposium
Ann Cahoon Department Head, Jewelry Making and Repair North Bennet Street School Boston, Massachusetts, USA
The first Bench Myths paper in 20141 asked some basic questions and started to explore some answers. Instead of asking more questions, this paper will expand on one topic explored in that research: annealing. It will continue the research by digging a little deeper into the variables of work surface, fluxes, the addition of soldering, and examining whether or not the choice of work surface and flux has a demonstrable effect on the workpiece.
Experiment
The number of soldering surfaces and fluxes available these days is impressive. If you take a look at a tool and supply website or catalog, you will find many options. A quick search for “soldering block” on the Rio Grande website delivers ten different types of soldering media, nine when you search Stuller, and nine when you search Gesswein®. After accounting for redundancy, there are about a dozen different options available between these three vendors. A search for “flux” gives you eight different hard soldering options from Rio Grande, five from Stuller, and five from Gesswein. There are no fewer than thirteen options after accounting for redundancy across these vendors. While these numbers aren’t huge independent of one another, when you look at potential combinations, that number grows to 156. That is a lot of options for a fundamental process!
It’s reasonable to ask, with so many options available, how much difference might this choice really make? Is it worth trying something new or perhaps revisiting options you haven’t explored in a while? This research is intended to offer some perspective on these questions.
For this experiment, I narrowed down the options into some commonly used broad categories: saving solution, liquid and paste fluxes, and charcoal and non- charcoal soldering surfaces. I elected to use hard charcoal and SolderiteTM brand soldering surfaces, a traditional boric acid saving solution, Superior #6 as the paste flux, and My-T-Flux for the liquid flux. Saving solution was mixed with two parts denatured alcohol to one part boric acid. Superior # 6 has a temperature range of 900–1600°F (485–870°C), and My-T-Flux a temperature range of 1100–1700°F (593–927°C).
There were two primary criteria in these selections. First, frankly, I like them all and use them regularly in my own shop. I have chosen to use them over the course of many years at the bench, and the process has been fairly organic, taking into account factors like convenience, safety and, most important, the results in the work. This is the pragmatic way many bench jewelers arrive at their preferences for soldering set-up, so it seemed a reasonable basis for comparison and experimentation. More significant for this project, however, is the fact that they represented the broad categories I wanted to represent in the research.
I tested the following combinations: paste flux only on the entire sample, liquid flux only on the entire sample, saving solution on the entire sample with paste flux only at the solder joint, saving solution on the entire sample with liquid flux only at the solder joint, and no flux on the sample with paste flux only at the solder joint, all on hard charcoal. An identical second set of samples was tested on a SolderiteTM pad.
Table 1 Sample preparation and soldering surface
Sample Number Soldering Surface Sample Preparation Sample Number Soldering Surface Sample Preparation
1–3 Hard Paste flux 16–18 SolderiteTM Paste flux 31–33 charcoal 46–48
4–6 Hard Liquid flux 19–21 Solderite Liquid flux 34–36 charcoal 49–51
7–9 37–39 Hard charcoal Saving solution, paste flux at the solder joint 22–24 52–54 Solderite Saving solution, paste flux at the solder joint
10–12 40–42 Hard charcoal Saving solution, liquid flux at the solder joint 25–27 55–57 Solderite Saving solution, liquid flux at the solder joint
13–15 43–45 Hard charcoal No flux or saving solution, paste flux at the solder joint 28–30 58–60 Solderite No flux or saving solution, paste flux at the solder joint
Samples for all experiments were .925 silver, 10 mm X 10 mm X 20 gauge. Each sample weighed 0.8–1.0 grams, and samples were randomized across the experiments. The goal was to have a small, jewelry-scale sample to mimic a real-world application of annealing and soldering processes. Since .925 silver is notorious for oxidation, it was the ideal choice for testing to create a “worst-case scenario.”
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Each sample was annealed once and hard soldered once. I used a Smith Handi- Heet® torch with a #2 tip. I considered using a more conventional dual fuel system for these experiments, but elected to use an atmospheric oxygen option to try to maintain consistency by eliminating the variables introduced by adjusting a gas/ oxygen flame. For annealing processes, I judged temperature by color or by flux surface, depending on the sample preparation. All samples were pickled for three minutes in a citric acid pickle after annealing, which was typically around 155°F (68°C) when checked throughout the experiment.
I used Hoover and Strong’s hard silver solder for the soldering operations, which has a melting point of 1370°F (743°C) and a flow point of 1490°F (810°C). The soldering step was laid out at the same position on each sample, 2 mm from the upper right corner. I used a 1.3 mm ball bur to create a small divot, following a common process used to locate small findings. Solder pallions were cut to a consistent size using shears and placed in the divots. Each piece was heated until solder flowed, following my established best practice. The heating process started opposite the solder location to begin to warm up the silver without affecting the flux too much, was followed by a more generalized heating step using the flux surface as an indicator of increasing temperature, and then finally moving on to work at the mock “seam” to flow the solder. A solder pick was used as needed to move pallions that had shifted back into position. Samples were then pickled again for three minutes.
Samples 1-30 (which will also be referred to collectively as Sample Group 1) were labeled and placed directly on the soldering surface called for in the experiment. All observations were strictly visual. Samples 31–60 (which will be referred to collectively as Sample Group 2) were intended for collecting more information about actual temperatures during the different experiments. After labelling this group, I laser welded bare thermocouple wire to samples 31-60 and used an OmegaTM HH11A thermometer to record temperatures. This was the same process used in the original “Bench Myths” research of 2014 to record annealing temperatures in the course of that annealing experiment. The thermocouple was positioned out of my view in front of a smart phone on a tripod, and each experiment was captured on video. Annealing temperatures and solder flow were announced as they were observed and the videos reviewed to determine at what temperature each process was observed.
Observations
Sample Group 1
Surfaces were observed after the initial annealing and pickling steps to judge the level of discoloration and oxidation, and to determine if there were any discernible differences between sample preparations. The results are shown in Table 2, with the cleanest surface in the first position. There was no significant difference in all 12 samples annealed with saving solution, though there was some level of variability across the group. The samples heated without flux on the SolderiteTM block showed the most discoloration and oxidation.
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Table 2 Ranking of Sample Group 1 after the annealing step
Ranking Sample Number Soldering Surface and Sample Preparation
1 7–9, 10–12, Saving solution, regardless of soldering surface 22–24, 25–27
2 16–18 Paste flux, SolderiteTM
3 1–3 Paste flux, charcoal
4 4–6 Liquid flux, charcoal
5 19–21 Liquid flux, Solderite
6 13–15 No flux or saving solution, charcoal
7 28–30 No flux or saving solution, Solderite
Sample Group 1 was then soldered and pickled, and the surfaces judged. Observations (without ranking) are shown in Table 3.
Table 3 Observations of Sample Group 1 after soldering (without ranking)
Sample Number
Soldering Surface and Sample Preparation
Observations
1–3
Paste flux, charcoal
Surfaces silver where there was flux coverage, other areas white from pickle, generally clean
4–6 Liquid flux, charcoal
More discoloration in flux, flux not completely removed by pickle
7–9
Saving solution,
paste flux at the solder joint, charcoal
Very consistently clean surfaces
10–12
Saving solution, liquid flux at the solder joint, charcoal
Very consistent clean surfaces, some discoloration around solder joint
13–15
No flux or saving solution, paste flux at the solder joint, charcoal
Clean at solder joint, obvious oxidation on the rest of the sample
16–18
Paste flux, SolderiteTM
Surfaces silver where there was flux coverage, other areas white from pickle, clean
19–21
Liquid flux, Solderite
Most discoloration in the flux of any of the samples, flux not completely removed by the pickle
22–24
Saving solution,
paste flux at the solder joint, Solderite
Samples very consistently clean
25–27
Saving solution, liquid flux at the solder joint, Solderite
Samples very consistently clean, some discoloration around solder joint
28–30
No flux or saving solution, paste flux at the solder joint, Solderite
Clean at solder joint,
obvious discoloration on the rest of the sample
Before determining a final ranking, all of Sample Group 1 was subjected to a final forced oxidizing step. All samples were gently heated to force discoloration in any oxidized area, with the goal of making any areas of oxidation more obvious. Samples were not pickled, again, to preserve the discoloration. Final ranking of samples is shown in Table 4.
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Table 4 Ranking of Sample Group 1 after forced oxidizing
Ranking
Sample Number
Soldering Surface and Sample Preparation
1 1–3 Paste flux, charcoal
2 19–21 Liquid flux, SolderiteTM
3 13–15
No flux or saving solution, paste flux at the solder joint, charcoal
4 4–6 Liquid flux, charcoal
5 7–9
Saving solution, paste flux at the solder joint, charcoal
6 28–30
No flux or saving solution, paste flux at the solder joint, Solderite
7 25–27
Saving solution, liquid flux at the solder joint, Solderite
8 16–18 Paste flux, Solderite
9 22–24
Saving solution, paste flux at the solder joint, Solderite
10 10–12
Saving solution, liquid flux at the solder joint, charcoal
Sample Group 2
The goal of Sample Group 2 was to determine what temperatures were achieved in these different approaches to begin to determine relationships between fluxes, soldering surfaces and actual working temperatures. Tables 5–14 and Figures 1–10 show results in both table and graph formats.
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Table 5 Temperatures observed in samples 31–33 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
31 1171 / 633 1416 / 769 1416 / 769
32 1184 / 640 1397 / 758 1433 / 778
33 1062 / 572 1431 / 777 1462 / 794
Figure 1 Observed temperatures (°F) in samples 31–33 during annealing and soldering
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Table 6 Temperatures observed in samples 34–36 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
34 1324 / 718 1468 / 798 1518 / 826
35 1350 / 732 1423 / 773 1450 / 788
36 1295 / 702 1443 / 784 1461 / 794
Figure 2 Observed temperatures (°F) in samples 34–36 during annealing and soldering
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Table 7 Temperatures observed in samples 37–39 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
37 1070 / 577 1403 / 762 1403 / 762
38 1275 / 691 1506 / 819 1540 / 838
39 1305 / 707 1518 / 826 1546 / 841
Figure 3 Observed temperatures (°F) in samples 37–39 during annealing and soldering
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Table 8 Temperatures observed in samples 40–42 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
40 1357 / 736 1370 / 743 1393 / 756
41 1302 / 706 1430 / 777 1430 / 777
42 1265 / 685 1453 / 789 1460 / 793
Figure 4 Observed temperatures (°F) in samples 40–42 during annealing and soldering
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Table 9 Temperatures observed in samples 43–45 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
43 988 / 531 1490 / 810 1511 / 822
44 1058 / 570 1481 / 805 1524 / 829
45 1213 / 656 1420 / 771 1425 / 774
Figure 5 Observed temperatures (°F) in samples 43–45 during annealing and soldering
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Table 10 Temperatures observed in samples 46–48 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
46 1026 / 552 1270 / 688 1270 / 688
47 1198 / 648 1411 / 766 1430 / 777
48 1070 / 577 1461 / 794 1498 / 814
Figure 6 Observed temperatures (°F) in samples 46–48 during annealing and soldering
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Table 11 Temperatures observed in samples 49–51 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
49 1294 / 701 1430 / 777 1430 / 777
50 1052 / 567 1425 / 774 1472 / 800
51 1301 / 705 1389 / 754 1425 / 774
Figure 7 Observed temperatures (°F) in samples 49–51 during annealing and soldering
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Table 12 Temperatures observed in samples 52–54 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
52 972 / 522 1439 / 782 1439 / 782
53 1025 / 552 1437 / 781 1437 / 781
54 1306 / 708 1391 / 755 1391 / 755
Figure 8 Observed temperatures (°F) in samples 52–54 during annealing and soldering
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Table 13 Temperatures observed in samples 55–57 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
55 1064 / 573 1428 / 776 1462 / 794
56 1238 / 670 1425 / 774 1433 / 778
57 980 / 527 1422 / 772 1422 / 772
Figure 9 Observed temperatures (°F) in samples 55–57 during annealing and soldering
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Table 14 Temperatures observed in samples 58–60 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
58 1080 / 582 1439 / 782 1467 / 797
59 1219 / 659 1099 / 593 1262 / 683
60 1194 / 646 1463 / 795 1463 / 795
Figure 10 Observed temperatures (°F) in samples 58–60 during annealing and soldering Figures 11-13 show us the aggregated data from all of Sample Group 2.
Figure 11 Aggregate of observed temperatures in °F, samples 31–45
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Figure 12 Aggregate of observed temperatures (°F) in samples 46–60
Figure 13 Aggregate of observed temperatures (°F) in Sample Group 2
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Figure 14 Aggregate of average observed temperatures (°F) in Sample Group 2 Comparisons and Conclusions
So what does an analysis of all of this data tell us? Figure 15 shows the temperature data from Sample Group 2 applied to the Ranking results from Group 1. Table 15 shows us temperature data applied to our original rankings, and notes the flux and soldering surface. What we see is that while there is some variability in the average soldering temperatures, the greatest variability lies in annealing. As the temperature trend line increases, the amount of oxidation on the samples also increases.
Figure 15 Temperature data (°F) from Sample Group 2 applied to the ranking results from Sample Group 1
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Table 15 Temperature data applied to original rankings with flux and soldering surface information
Ranking
Average Annealing Temperature °F / °C
Average Soldering Temperature °F / °C
Soldering Surface
Annealing Preparation
Soldering Preparation
1 1139 / 615 1415 / 768 Charcoal Paste flux Paste flux
2 1216 / 658 1415 / 768 SolderiteTM
Liquid Liquid flux flux
3
1086 / 586
1464 / 796
Charcoal
No flux or saving solution
Paste flux
4 1323 / 717 1445 / 785 Charcoal
Liquid Liquid flux flux
5
1217 / 658
1475 / 802
Charcoal
Saving solution
Saving solution with paste flux at the joint only
6
1153 / 623
1451 / 788
Solderite
No flux or saving solution
Paste flux at the joint only
7
1094 / 590
1425 / 774
Solderite
Saving solution
Liquid flux at the joint only
8 1143 / 617 1436 / 780 Solderite Paste flux Paste flux
9
1101 / 594
1422 / 772
Solderite
Saving solution
Paste flux at the joint only
10
1308 / 709
1418 / 770
Charcoal
Saving solution
Liquid flux at the joint only
The connection between soldering surfaces and the amount of oxidation on the surfaces isn’t quite as clear if looking only at general trends, though the general trend in the data indicates that the samples annealed and soldered on charcoal were generally less oxidized. The samples ranked 7, 8, and 9 are particularly important in drawing a conclusion, however. All have nearly ideal average temperatures, yet they are some of the most oxidized. What we must note is that they were all annealed and soldered on SolderiteTM. When you look further at the fact that two of the lesser oxidized samples (rankings 4 and 5) had higher average annealing temperatures but were heated on charcoal, the role of the soldering
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surface as a critical contributor to the whole picture becomes clearer. Charcoal’s ability to provide a reducing environment appears to have very demonstrable effects on soldering and annealing outcomes.
While the use of a flux was not always associated with a less oxidized result, the top two results used a flux on all surfaces for both annealing and soldering.
An additional important observation is that the top two rankings are associated with the approaches I tend to use in my own studio practice. This is not to say that they are, therefore, the best practices. Rather, I think it underscores the very real implications practice and experience have on any set of variables.
References
Cahoon
Table 4 Ranking of Sample Group 1 after forced oxidizing
Ranking
Sample Number
Soldering Surface and Sample Preparation
1 1–3 Paste flux, charcoal
2 19–21 Liquid flux, SolderiteTM
3 13–15
No flux or saving solution, paste flux at the solder joint, charcoal
4 4–6 Liquid flux, charcoal
5 7–9
Saving solution, paste flux at the solder joint, charcoal
6 28–30
No flux or saving solution, paste flux at the solder joint, Solderite
7 25–27
Saving solution, liquid flux at the solder joint, Solderite
8 16–18 Paste flux, Solderite
9 22–24
Saving solution, paste flux at the solder joint, Solderite
10 10–12
Saving solution, liquid flux at the solder joint, charcoal
Sample Group 2
The goal of Sample Group 2 was to determine what temperatures were achieved in these different approaches to begin to determine relationships between fluxes, soldering surfaces and actual working temperatures. Tables 5–14 and Figures 1–10 show results in both table and graph formats.
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Table 5 Temperatures observed in samples 31–33 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
31 1171 / 633 1416 / 769 1416 / 769
32 1184 / 640 1397 / 758 1433 / 778
33 1062 / 572 1431 / 777 1462 / 794
Figure 1 Observed temperatures (°F) in samples 31–33 during annealing and soldering
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Table 6 Temperatures observed in samples 34–36 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
34 1324 / 718 1468 / 798 1518 / 826
35 1350 / 732 1423 / 773 1450 / 788
36 1295 / 702 1443 / 784 1461 / 794
Figure 2 Observed temperatures (°F) in samples 34–36 during annealing and soldering
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Table 7 Temperatures observed in samples 37–39 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
37 1070 / 577 1403 / 762 1403 / 762
38 1275 / 691 1506 / 819 1540 / 838
39 1305 / 707 1518 / 826 1546 / 841
Figure 3 Observed temperatures (°F) in samples 37–39 during annealing and soldering
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Table 8 Temperatures observed in samples 40–42 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
40 1357 / 736 1370 / 743 1393 / 756
41 1302 / 706 1430 / 777 1430 / 777
42 1265 / 685 1453 / 789 1460 / 793
Figure 4 Observed temperatures (°F) in samples 40–42 during annealing and soldering
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Table 9 Temperatures observed in samples 43–45 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
43 988 / 531 1490 / 810 1511 / 822
44 1058 / 570 1481 / 805 1524 / 829
45 1213 / 656 1420 / 771 1425 / 774
Figure 5 Observed temperatures (°F) in samples 43–45 during annealing and soldering
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Table 10 Temperatures observed in samples 46–48 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
46 1026 / 552 1270 / 688 1270 / 688
47 1198 / 648 1411 / 766 1430 / 777
48 1070 / 577 1461 / 794 1498 / 814
Figure 6 Observed temperatures (°F) in samples 46–48 during annealing and soldering
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Table 11 Temperatures observed in samples 49–51 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
49 1294 / 701 1430 / 777 1430 / 777
50 1052 / 567 1425 / 774 1472 / 800
51 1301 / 705 1389 / 754 1425 / 774
Figure 7 Observed temperatures (°F) in samples 49–51 during annealing and soldering
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Table 12 Temperatures observed in samples 52–54 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
52 972 / 522 1439 / 782 1439 / 782
53 1025 / 552 1437 / 781 1437 / 781
54 1306 / 708 1391 / 755 1391 / 755
Figure 8 Observed temperatures (°F) in samples 52–54 during annealing and soldering
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Table 13 Temperatures observed in samples 55–57 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
55 1064 / 573 1428 / 776 1462 / 794
56 1238 / 670 1425 / 774 1433 / 778
57 980 / 527 1422 / 772 1422 / 772
Figure 9 Observed temperatures (°F) in samples 55–57 during annealing and soldering
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Table 14 Temperatures observed in samples 58–60 during annealing and soldering
Sample number
Annealing Temperature Observed °F / °C
Soldering Temperature Observed °F / °C
High Temperature Observed °F / °C
58 1080 / 582 1439 / 782 1467 / 797
59 1219 / 659 1099 / 593 1262 / 683
60 1194 / 646 1463 / 795 1463 / 795
Figure 10 Observed temperatures (°F) in samples 58–60 during annealing and soldering Figures 11-13 show us the aggregated data from all of Sample Group 2.
Figure 11 Aggregate of observed temperatures in °F, samples 31–45
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Figure 12 Aggregate of observed temperatures (°F) in samples 46–60
Figure 13 Aggregate of observed temperatures (°F) in Sample Group 2
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Figure 14 Aggregate of average observed temperatures (°F) in Sample Group 2 Comparisons and Conclusions
So what does an analysis of all of this data tell us? Figure 15 shows the temperature data from Sample Group 2 applied to the Ranking results from Group 1. Table 15 shows us temperature data applied to our original rankings, and notes the flux and soldering surface. What we see is that while there is some variability in the average soldering temperatures, the greatest variability lies in annealing. As the temperature trend line increases, the amount of oxidation on the samples also increases.
Figure 15 Temperature data (°F) from Sample Group 2 applied to the ranking results from Sample Group 1
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Table 15 Temperature data applied to original rankings with flux and soldering surface information
Ranking
Average Annealing Temperature °F / °C
Average Soldering Temperature °F / °C
Soldering Surface
Annealing Preparation
Soldering Preparation
1 1139 / 615 1415 / 768 Charcoal Paste flux Paste flux
2 1216 / 658 1415 / 768 SolderiteTM
Liquid Liquid flux flux
3
1086 / 586
1464 / 796
Charcoal
No flux or saving solution
Paste flux
4 1323 / 717 1445 / 785 Charcoal
Liquid Liquid flux flux
5
1217 / 658
1475 / 802
Charcoal
Saving solution
Saving solution with paste flux at the joint only
6
1153 / 623
1451 / 788
Solderite
No flux or saving solution
Paste flux at the joint only
7
1094 / 590
1425 / 774
Solderite
Saving solution
Liquid flux at the joint only
8 1143 / 617 1436 / 780 Solderite Paste flux Paste flux
9
1101 / 594
1422 / 772
Solderite
Saving solution
Paste flux at the joint only
10
1308 / 709
1418 / 770
Charcoal
Saving solution
Liquid flux at the joint only
The connection between soldering surfaces and the amount of oxidation on the surfaces isn’t quite as clear if looking only at general trends, though the general trend in the data indicates that the samples annealed and soldered on charcoal were generally less oxidized. The samples ranked 7, 8, and 9 are particularly important in drawing a conclusion, however. All have nearly ideal average temperatures, yet they are some of the most oxidized. What we must note is that they were all annealed and soldered on SolderiteTM. When you look further at the fact that two of the lesser oxidized samples (rankings 4 and 5) had higher average annealing temperatures but were heated on charcoal, the role of the soldering
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surface as a critical contributor to the whole picture becomes clearer. Charcoal’s ability to provide a reducing environment appears to have very demonstrable effects on soldering and annealing outcomes.
While the use of a flux was not always associated with a less oxidized result, the top two results used a flux on all surfaces for both annealing and soldering.
An additional important observation is that the top two rankings are associated with the approaches I tend to use in my own studio practice. This is not to say that they are, therefore, the best practices. Rather, I think it underscores the very real implications practice and experience have on any set of variables.
References
I use boric acid powder to “cure” new clay crucibles for pouring ingots. Been doing it for years. Not sure that I notice a difference between boric acid and borax in this application tough….
I use Battern’s flux.
Battern’s flux contains boric acid. Up to 10% of it is boric acid.
Also contains ammonium chloride and Sodium Tetraborate
Decahydrate … and water.
I used Battern’s for a few years because my Dad did. I wasn’t a huge fan because it could create some pretty impenetrable glazing depending on how hot it got. I began using Boric Acid and Alcohol and found it to fit the work I was doing pretty well. And I still use it. I have also used Borax in a water suspension as a fire coat and combined with Battern’s(As little as possible) only at the joints found that acceptable in some to most applications. Usually with brass and copper combined pieces. I like Boric Acid and Solvent Alcohol because it washes away easily in hot soapy water and it helps limit scale. Of Course fire safety is a must with a Molotov Cocktail on the bench but a silversmith is nothing if not daring.
Don Meixner
Thank you for your reply.
Both ethyl and methyl alcohol are now unavailable in California. I’m seeking an alternative alcohol. Do you have any other suggestions?
FYI:
I purchased the boric acid from RioGrande. This is a video explaining how to make the flux.
Again, I’m seeking help on alternative alcohols to use since methyl and ethyl alcohol is no longer available in California.
And yes, I was able to order a gallon as well. Apparently, exsisting stock can continued to be sold. But what to do after it runs out?
Make your own?
boric acid will dissolve somewhat less in isopropyl. It is rubbing alcohol. Where I live you can get it 99%. But I suppose 70% will work. Also check out the fuel used for heating dishes used in serving tables. Look also for a high ABV drinking alcohol. (ABV = alcohol by volume) Check vodka which I believe is about 40% . Try something called ever clear. As I understand it this comes 60% and more. sorry that I am now out of my knowledge range as I am in Ontario Canada and do not have any of the issues that you are experiencing. You can distil vodka to 80% very easily but suspect this may not be legal for you.
Also look up gel alcohol and hand sanitizer. Hand sanitizer where I am is often 80 %ABV. I recall that table salt will remove the gel in a sanitizer but I do not know haw that will affect it for our use.
I will give this some thought though.
Yes. Everclear in 190 proof form (~95% ethanol) from your neighborhood liquor store would work. Unfortunatly, you’ll have to pay liquor tax on it, but, at least you could drink it if you quit making flux with it.
– a
As a general comment, I have found that when using alcohol that is less than 99% the boric acid forms crystals at the bottom of the container. I believe that the water (which is the remaining %) is causing this. I’m not sure whether that takes away the benefit of the boric acid completely or partly. You can tell that I’m an artist, not a scientist. lol
There is another solution called Pripp’s Flux which is water-based and can be used instead of alcohol and boric acid. Years ago I saved a wonderful description of how to make and use it written right here on Orchid. It was written by Peter Rowe, who is a knowledgeable and talented jeweler and regularly shares information, so I’m sure he won’t mind my reproducing his description here.
It constantly surprises me how many people who've worked for
quite a while with silver seem to still have significant problems
with fire scale on sterling.
hey folks, it's not hard to prevent. The cure is called pripps
flux, which you spray coat your pieces with before any and all
annealing or soldering operations. I first wrote a quick
article about pripps flux several years ago, and it's proved
useful enough that from time to time I republish that
description. It sounds as though some in this thread could use
it again. here tis. enjoy. (sorry about the odd formatting of
the article. I cut and pasted it from a copy with fixed line
lengths into my newsreader...)
Peter Rowe
Pripps Flux
Pripp's flux is a mix you make up yourself, and it works pretty
much the same as a borax coat, which is the older and more
traditional method. Classical silversmiths would often go through
several sequences of "burning on" a borax coat before annealing
or soldering, but it doesn't work quite as easily or as well as
Pripp's.
I've been a gold and silversmith since college, and learned
Pripp's from Prof. Fred Fenster at the University of Wisconsin,
who proclaimed in that 1972 sophomore class that at other schools
people sometimes complained about firescale, but "here at U.W. it
never gives us a problem". This, by the way, was taught from the
first moment we were shown how to light a torch, just to give you
an idea of how important and basic a technique Fred felt it was.
It's named after Jack Pripp, who taught at Rochester for many
years, and is considered one of the fathers of the American
metalsmithing community.
To make it, you will need: a quart of water, 120 grams boric
acid, 80 grams each TSP (trisodium phosphate) and borax. Boil to
dissolve it (you might have to add a little more water. It's the
3:2:2 ratio that's important, not the concentration.). The Borax
you can get at the supermarket, in the laundry area. (Borateem
is just borax- the little green flecks they put in there too
don't seem to matter). TSP (trisodium phosphate) is a strong
alkaline cleaner often used in cleaning walls and the like before
painting. You can usually get it in paint or hardware stores, but
be sure it's actually trisodium phosphate. Because it's rather a
caustic (though reasonably safe) material, some stores carry a
substitute, which may be confusingly labeled. (eg.TSP brand
wall-cleaner no longer contains TSP.) Read the box carefully.
The substitute doesn't work for this purpose. If you happen to
have a chemical supply house around, you can also use disodium
or monosodium phosphates. But the trisodium formula seems to be
the most common.
You apply it (and this is an important detail) by spraying it on
the silver while gently heating the silver up enough so the spray
dries on contact, as opposed to hitting as a liquid and
bubbling/boiling off. The best sprayers by far are the cheap
little two-tube-with-a-hinge mouth atomizers that ceramics folks
sometimes use for applying glazes. It gives a much finer and more
uniform spray than any sprayer bottle I've seen, and cannot
clog.
To use it, you' gently brush the metal with the flame, then with
quick short puffs on the sprayer, put the Pripp's flux on a
little at a time. The idea is to coat the entire piece with a
thin white crusty coating, thick enough so that reflections from
the metal are no longer visible, but no more. Be careful, as you
do this, neither to let the metal cool so much that the flux
stays liquid (it doesn't coat evenly then), or that the metal
gets so hot that it starts to discolor. It's easy enough, but
takes a little practice at first. Coat all the parts of your
assembly, then let them cool, set up the joint, and with the
addition of the smallest amount of additional soldering flux only
in the joint (see below) and solder, do the soldering job.
Pripp's is a much less active flux than the paste fluxes, and
doesn't burn off easily (though with enough overheating you can
do it), so it gives continuous protection, and thereby completely
prevents fire scale. It will work as a soldering flux all by
itself IF your metal and solder are both completely clean before
you start, and if your heat control is good. Paste fluxes such as
the "Handy" or Griffin brands, oddly enough, seem to provide
little or no firescale protection. In fact, with some metals
(like white golds) you'll find the firescale is worse where the
flux was. This is why you don't want to use much, and should keep
it only in the join area. But they are so very active while still
fluid that they greatly promote solder flow, so many of us use
them anyway. Battern's self-pickling flux is somewhere in
between- it lasts longer and doesn't give quite the fire scale
problem, but also doesn't protect quite as well.
In my work, for simple repairs to already-made silver jewelry, I
usually just use a boric acid/alcohol coat, solder with paste
flux, and clean up later, as most of these pieces already have
fire scale, and for a single quick ring shank solder job or what
have you, it's not worth the trouble to bring out the Pripp's.
But if I'm making something from scratch, then (with a few
exceptions), every last annealing or soldering step is done with
Pripp's coating everything.
The added time and bother is more than paid back when it's time
to finish the piece- when there's no surface oxide and no fire
scale, then the piece can be polished out as easily as gold
work. This coating, if you are careful and don't pickle it off
after soldering, can usually last through several soldering
cycles; so for some complex assemblies; if you've got everything
fitted before hand, you may only need to coat the parts once for
a number of sequential soldering steps. Also, since the sprayers
tend to cover rather more area than just your silver (like the
tools and bench areas behind your soldering area), you will want
to set up some sort of simple shield behind the area you're using
for spraying on the flux to catch that over spray. This saves a
lot of mess.
Peter Rowe
Yeah, Everclear not available in California either.
Small point:
I would avoid using methanol, as it is a neurotoxin and is absorbed through skin, lungs etc.
I wonder is isopropyl would work ?
Sorry, we live in a too safe environment at time i.e. why ban denatured alcohol (even if dose contain ` few percent methanol)