Benchtop Hydroflux Welders

Connections are an important part of jewelry manufacturing. We make them with suppliers, with retailers, even with the people who buy and wear our jewelry. But some of the most important connections are those we make between metals. Whether creating custom one-offs or producing in volume, jewelers must constantly make physical connections between metal objects ear posts to earrings, clasps to chains, and jump rings to nearly everything.

14 Minute Read

By John ShanahanMore from this author

This article originally appeared in the January 2000 issue of AJM Magazine. Visit AJM on the Web at

Making Connections

With the help of technology, attaching metals has never been easier. Connections are an important part of jewelry manufacturing. We make them with suppliers, with retailers, even with the people who buy and wear our jewelry. But some of the most important connections are those we make between metals. Whether creating custom one-offs or producing in volume, jewelers must constantly make physical connections between metal objects, ear posts to earrings, clasps to chains, and jump rings to nearly everything. And more and more, they are looking toward newer technology to help them do so in less time, at lower cost, and with greater convenience.

Recently, I had the opportunity to experiment with several benchtop welding units that, to varying degrees, achieve those aims. These units, two water welders and three fusion welders, may operate under different principles, but all increase efficiency: Some save considerable time, some save money, and some simply increase the flexibility of shop operations. All, however, prove the value of incorporating technology into the shop.

The first units I tested were the water welders. These machines have been around in the jewelry industry for some time now,at least 15 years, according to Mike McCoy, vice president of the Union, New Jersey-based Okai Corp., manufacturer of the Hydroflux welder. While water welders are not the newest innovation in the industry, continued refinements have reduced their size and cost. Among their benefits, the most important is that they eliminate the potential danger of storing flammable bottled and piped gases. Instead, they generate  hydrogen and oxygen on site from the breakdown of distilled water. This is especially important with bottled gas; normally purchased and stored in pressurized containers, it is coming under increasing regulation and may be prohibited in some areas.

The two machines I tested were the Okai Hydroflux and the SRA H2O #250 welders. While each shares basic operating characteristics, they differ in several ways. Both machines generate fuel gas by sending an electrical current through distilled water, the conductivity of which has been improved by the addition of an electrolyte, potassium hydroxide. The current breaks the bonds between the oxygen and the hydrogen atoms of the water molecules, releasing them as a mixed gas. That gas is then "bubbled" through a fluxing solution of methyl alcohol and boric acid.

This solution, which becomes incorporated into the fuel gas, performs two functions. First, it lowers the burning temperature of the flame from around 5,600 degrees F to 4,850 degrees F, helping operators to avoid inadvertently melting parts. (Conversely, this temperature reduction increases the flame's BTU value.) Second, the boric acid helps protect the object being soldered from oxides and fire scale. This is further helped by the high hydrogen content of the flame, which produces a reducing atmosphere that eliminates some of the potential for oxidation present in most fuel gases. (It should be noted that the fluxing action and reduction flame do not eliminate the use of pre-dip and flux at the solder joint.)

I can't recall when, but at some point in the past I had formed an impression that the flame from water welders didn't compare favorably with my trusty old oxy-acetylene setup. It might have been from observation; the water welder'storch tip is nothing more than a short hypodermic-type needle, the appearance of which looks pretty funny to a bottled gas user. But while the flame may seem small and anemic, in this case looks are deceiving: The flame is actually hot and precise. One adjustment I did have to make was in learning the feel of the hotter hydrogen flame,welds occur much faster with such high heat,but I acclimated quickly.

Suitable for small-scale jobs up to and including the sizing of a man'sring, these welders performed very well in all areas of benchwork. I found that they did indeed generate less soldering "mess" in the form of oxides. Also, both torches performed as well or better than the oxy-acetylene system I typically use. The only advantage with my old oxy-acetylene torch and its interchangeable tips is that I can generate a huge flame when necessary, such as when sizing a large silver ring with a gem that must be immersed in water for heat protection.

Both welders also offer the benefit of portability. When their methanol/boric acid chambers are emptied, these machines can travel with craftsmen who take their benches with them for demonstrations, or for on-site repair and sizing in the growing "craft show" venue. Even in a static shop situation, the portability of these machines may prove useful, since they can be moved from bench to bench easily.

The two machines do have some differences. The SRA machine has a relatively small footprint, 11 inches by 6.5 inches, while the Hydroflux welder is a little larger,16 inches by 10 inches. Also, the Hydroflux flame can be controlled by simply changing the torch tip; the unit has a pressure switch that reacts to a tip'ssize, cycling on to maintain a pressure of about 3 psi. The SRA machine uses a combination of amperage to regulate gas output and tip size to regulate flame, so that gas output can be more specifically matched to a job.

Although both welders performed admirably, I had to wonder: Would I be paying more if I did away with bottled gas,+ I decided to find out and called my bottled gas supplier, who provided a price of $34.10 for a container holding 197 cubic feet of gas. Since one cubic foot converts to 28.317 liters, the math reveals that I pay about 0.6 cent for a liter of bottled hydrogen. With gas cylinder rental at about $6.50 per month, I speculated that bottled hydrogen approaches about 1 cent per liter overall,a crude cost comparison, but a start.

I also needed to determine how much the water welder would cost in electricity, an expense I don't have with my oxy-acetylene hookup. I called the president of SRA, Stan Rubinstein, who said that the #250 produces about 45 liters per hour and uses about the same electricity as a 150-watt bulb. McCoy agreed with that estimate for his machine as well. I then contacted Michael Lang, an energy management specialist with my local utility company in Eugene, Oregon; he informed me that the average residential cost for operating a 150-watt bulb for one hour is roughly .006 cent.

Dividing that figure by 45 liters of gas gives me a cost of .0001333 cent per liter. I had to add in the overhead of about $138 per year for electrolyte, methanol, and boric acid,but then I remembered that bottled hydrogen requires bottled oxygen, which costs about $16 per bottle. Given this, it seems a fair assessment to say that these water welders produce fuel gas less expensively than my current setup with bottled gas. With an initial capital outlay that can run up to about $1,100, these machines seem like a good investment for any jewelry manufacturing business.

Fusion Fun

Another method of making connections does not involve any fuel gas at all. Fusion welding systems have been a mainstay in the jewelry industry for many years; properly set up and used, they can provide fast, clean bonds between similar and dissimilar metals.

Some of these systems require the use of specially designed findings (available from many suppliers) that have a small, approximately 0.01 inch diameter,nib in the center of a flat contact plate. The actual welding takes place when an electrical charge flows, by a process called capacitive discharge, through a fusion finding touching the surface of the receiving metal. A small explosion occurs, which blows all of the oxides and gases away from the weld. For the next millionth of a second or so, a vacuum exists, allowing metals to bond in the residual heat.

One such fusion welder is the Sparkie II, manufactured by Triad Inc. in Chartley, Massachusetts. During my tests, I found it to be a potentially useful tool for manufacturers involved with high production numbers and standard, or at least predictable, shapes that can accommodate the nibbed finding (e.g., tie tack backs and earring posts). Success with the Sparkie involves the coordination of pre-fit moving parts: a spring-loaded cylinder with a collet that holds the fusion finding, and a jig that steadies the workpiece and engages the collet. The jig, jig holder, and collet have interchangeable parts for adaptation to different welding applications.

For the uninitiated, the Sparkie welding process can seem very dramatic, but it'sactually very simple and straightforward. The cylinder is engaged by locking it in position with spring tension. The fusion finding is placed into the collet, and the unit'scapacitor is charged simply by pressing a button and observing the voltmeter.
(Though determined by the parts to be joined, the charge usually falls in the 80 volt to 120 volt range.) The operator places a workpiece in the jig, holding it in place with a finger (properly protected, of course, by a rubber glove). With the release of the cylinder, the finding plunges toward the piece. A brief pop, a small spark, and you have an immediate, secure bond. A slight residue of carbon left around the welded parts can be easily wiped or washed off. The instruction manual provided with the Sparkie adequately explains the process of setting and maintaining the machine. The unit can accommodate custom jigs, including a Triad-supplied fixture disk in which jewelers can make impression molds in a two-part polymer.

One important note about quality control, as stated in the Sparkie instruction manual: 'the simplicity and speed of fusion welding can be misleading. Proper alignment of the machine and preparation of the pieces to be welded is very important and cannot be overemphasized.' In my experience, I found that in most cases improper alignment resulted in a failed bond. But even considering the care needed to properly align parts, I feel that the Sparkie II may be an invaluable tool for production welding applications, resulting in increased output compared to traditional soldering. With very little practice, I found that we could weld about six to 10 parts per minute,which is about four to five times as many as I could do through torch soldering.

Off the Beaten Tack

While the Sparkie works well with predictable applications, another system offering increased flexibility is the Tack II. This fusion-bonding machine, manufactured by Aelectronic Bonding Inc. in Cranston, Rhode Island, works similarly to the Sparkie II. However, it'sgeared not toward permanent bonds, but toward the pre-weld step of precisely aligning parts.

The Tack II basically comprises a capacitor; one electrical lead attached to a copper contact pad; and one other lead connected to a fusion pencil, a pair of tweezers, or any of several other electrical conductors. As with the Sparkie, the capacitor produces an electrical current between the lead and the workpiece, producing a bond. It's important for an operator to experiment with voltage levels. With too little voltage, the bond may not occur. And with too much voltage, a small part could be fairly well vaporized,as we nearly did a few  times.

To illustrate the Tack II'soperation, let me describe how I used it to place prong heads on a ring mounting. Holding the ring mounting to the contact pad, I used the tweezers to hold the prong head in the desired position. I then depressed a foot pedal to discharge the capacitor, which ran a sufficient current between the two parts to tack them in place.

This procedure works well for any assembled part requiring precise alignment, especially since it allows for mistakes: If you don't get the correct position on the first try, you can twist the prong head away from the mounting and repeat the procedure. Once the parts are in place, traditional soldering permanently attaches the head or other object. The instruction booklet and video that accompany the unit provide numerous similar examples of ways to use this handy machine, such as the always tricky tacking of chain ends together and the fabrication of free-form parts.

One use that I wasn't able to try,but am anxious to experiment with,involves a new way to place beads for granulation. One of the discharge attachments available with the Tack II is a small tube to which a miniature vacuum device is attached. The vacuum can be used to pick up a single bead and hold it in place on a surface to be granulated. Upon discharge, the bead is minutely fused to the surface, securely held in place without the necessity of any chemical glue. When all beads are placed, you can then fuse them to the metal through oven soldering. I can only imagine how much time this could save an artisan involved with granulation.

Another machine built and distributed by Aelectronic Bonding, the Tack III, is another beast altogether. Originally designed for the specific use of tacking hollowware halves prior to oven soldering, the Tack III is actually an "arc welding pencil",which means it also uses capacitive discharge to fuse metal, but in a different way. It uses a tungsten electrode that, when held a very slight distance away from the piece to be welded, passes an electrical arc that liquefies the metal and forms a bond.

Because this process will occasionally cause oxidation around the point of contact, the Tack III has been designed so that an argon gas line can be attached to the welding pencil. The tungsten electrode of the welding pencil is housed in a ceramic casing that has a diameter slightly larger than that of the electrode; this allows the inert gas to flow around the electrode and bathe the arc and surrounding metal in a non-oxidizing argon atmosphere. When the foot pedal is depressed, the gas line is activated a split-second before the discharge takes place, so very little gas is used in the process.

Safety is, as with any tool, an issue with these fusion and arc welding devices. A painful shock could be experienced if the operator'sskin becomes the path of least resistance for the capacitor discharge. Rubber gloves are advisable, and some sort of eye protection is mandatory. For better corneal protection, you can wear dark welding glasses,I recommend #5 shades at a minimum,but they make  it difficult to see anything but the spark. Since the capacitor discharge is so brief for all of these machines, I found it routine to blink as the discharge takes place. Another, safer method is simply to look away.

When these safety precautions are in place, I found the Tack III to be of great value. In fact, I had the machine set up for no more than about a day when I discovered just how useful it could be. A new client came into the shop with a necklace of beaded amber and pearl strung on nylon, and she pointed out that the end caps had pulled away from the clasp. The traditional repair would have called for restringing with a stronger end cap or stringing directly to the clasp. For her necklace, a multi-strand, I estimated the cost would have been around $65.

Remembering the technology I had recently acquired, I made her a proposal. I would try to fuse the tab end of the end cap with the Tack III so that it would not pull loose again. If successful, I would charge her only my shop minimum, $15. If not, I would complete the repair in the traditional method and she would pay the full $65.

Honestly, I was surprised at how well the system worked. My weld was a bit sloppy, since I had had only a day of practice, but the tool worked perfectly. Not only did I successfully fuse the end cap tab, I did it without melting the nylon to which it was strung! I saved my client $50 on her first job with me, completed it while she waited, and perhaps gained a client for life.

In the days that followed, my workers and I became very comfortable with the Tack III, finding it useful for various routine shop procedures. We rarely use a torch now for soldering jump rings; the Tack III produces a perfectly bonded jump ring in seconds with no cleanup needed. I've also used it to fuse metal in casting pits, with great success.

Of course, sometimes we have to live with a new technology before all of the possible uses are discovered. But finding those uses is one of the many things that excite me about my work, and about the jewelry industry as a whole. I have a friend, a ceramist, who ebulliently expresses her connection to her medium by proclaiming, 'touch clay every day'. As jewelers, we have very much the same connection with our metal,and, with tools such as these welders, that connection will no doubt continue to evolve.

Editor's Note

In addition to thanking the manufacturers of the products tested for this article, AJM would like to thank Eisinger Enterprises in Newark, New Jersey, for its help in procuring the Sparkie II fusion welder and the Hydroflux water welder.

Welders Reviewed

Hydroflux Water Welder
Okai Corp., Union, New Jersey
Price: $975

SRA H2O #250
SRA Inc., Foxboro, Massachusetts
Price: $1,075

Sparkie II
Triad Inc., Chartley, Massachusetts
Price: $1,195

Tack II
Aelectronic Bonding Inc., Cranston, Rhode Island
Price: $1,295

Tack III
Aelectronic Bonding Inc., Cranston, Rhode Island
Price: $3,900

By John Shanahan
© AJM magazine 2000 January
Associate Editor, AJM magazine
Editor, AJM Online
800-444-6572, ext. 3037

You assume all responsibility and risk for the use of the safety resources available on or through this web page. The International Gem Society LLC does not assume any liability for the materials, information and opinions provided on, or available through, this web page. No advice or information provided by this website shall create any warranty. Reliance on such advice, information or the content of this web page is solely at your own risk, including without limitation any safety guidelines, resources or precautions, or any other information related to safety that may be available on or through this web page. The International Gem Society LLC disclaims any liability for injury, death or damages resulting from the use thereof.

John Shanahan

The All-In-One Jewelry Making Solution At Your Fingertips

When you join the Ganoksin community, you get the tools you need to take your work to the next level.

Become a Member

Trusted Jewelry Making Information & Techniques

Sign up to receive the latest articles, techniques, and inspirations with our free newsletter.