I’ve made my own solders using silver and copper. I agree with you that zinc is reactive and will get into enamel. Not all bimetallic alloys have a eutectic point. Gold/silver forms a solid solution over all compositional ranges. Solid solutions do not have eutectic melting point. Gold/copper has a pseudo eutectic at 60/40% as it’s not a sharp point on the compositional curve, with a broad melting point that varies from about 60 to 65% gold. Eutectic mixtures have both components solidify simulateous, creating a lamellar microstructure (microstrips of alternating metals)… Old fashion lead/tin solders (now banned) also have a eutectic point… What I have found experimentally is that eutectic silver/copper is too gray… moving off the eutectic by adding more silver brightens up the metal… the melting point will rise but still is significantly below the melting point of either pure metal. The mushy state that you mention is typical for trimetallic mixtures and also occurs with steel and water as slush… this is the transition zone between solid and liquid states… Once the mush melts, at least with zinc containing solders, flow is enhanced, hence the “flasihing” with zinc containing silver solders. These properties are contrained by thermodynamics… the Gibb’s free energy of the transition from the liquidus to solidus states are the lowest at eutectics.
This is far too theoretical for a home hobbyist or even a commercial jeweler…it’s also off the topic. For enameling, the enamel will cover up the joints…so using eutectic silver and copper doesn’t matter… for soldering visible joints, the joint is too gray…that’s the practical part. That being said, I still found that phase diagrams are a useful guide.
Rob,
You’re most welcome! I am delighted to be in a position to offer something of value to others.
I empathize with your particular situation because I was in the same place just a few short years ago. Like you, I felt lost and didn’t know where to start. I also imagined taking classes might be the quickest path to success, but for me that route turned out to be an expensive dead end. I had to fall back upon autodidact skills and learn enameling the same way I learned wood carving, marquetry, inlay, machining skills, and engraving, i.e. teaching myself through trial and (lots of) error. After having taken that journey, I have suggestions that may potentially be of use to you.
First and foremost, don’t be afraid to dive in and learn by doing. Yes, it takes an investment of time and materials. And yes, it’s a given that you WILL make mistakes that waste time and materials. But there’s no better teacher than experience. Mucking up a job teaches one what NOT to do next time around. One’s own mistakes are remembered long after third party advice from a class has faded away and been forgotten. Eventually the collection of knowledge of what not to do becomes large enough to significantly enhance one’s chances of achieving consistent successes.
I’m a professional screw-up, so I’m still able find ways to muck up a job even though I have a couple of years worth of hard-won experience (see enameling over zinc-bearing solder in a previous post!). Learning is a life-long pursuit, which in my view is actually a good thing! Our lives would become unbearably dull if we no longer had anything left to learn from screwing up.
Just as with shade-tree mechanics, many people decide to earn extra income by monetizing their hobby. Unfortunately, the result is that many people offering classes are not REMOTELY qualified to teach ANY subject, much less enameling! It only took me a couple of poorly-instructed classes before calling it quits. But my friend Paul Hamler has taken a number of classes taught by various instructors – including one that works for a well known jewelry supply vendor that has tutorial videos posted on YouTube! He told me that most of these classes were a complete waste of his time and money because the instructor knew barely enough to light a torch. For example, one consistently over-fired every piece and ended up with “burnt” enamel that looked dull and lifeless. When Paul mentioned it to the instructor, the reply was, “I like that look!” This same instructor left fire scale on the edges of enameled copper plate, again insisting he liked the look. The paintings of Jackson Pollack and the works of this enameling “instructor” prove there’s no accounting for taste.
If you can’t find a qualified instructor near you offering classes with a money back guarantee, I highly recommend the instructional videos of Sandra McEwen. She is a master enamelist with a global following:
She has literally hundreds of videos on her YouTube channel that cover every aspect of enameling you’re ever likely to want to learn. There are videos for every skill level from raw beginner to expert enamelist. They cover nearly all the different enameling techniques:
They also cover the entire range of learning styles from a brief executive summary for those with
limited time needing just the highlights of a process delivered as quickly as possible, to deep-dive step-by-step tutorials for those wanting to see every excruciatingly tedious detail of a process so as not to overlook even the smallest but still important tip.
She has both free and subscription-only content on her YouTube channel:
Full Disclosure: I don’t know Sandra McEwen, nor do I receive compensation of any kind for promoting her training videos. I simply believe in giving credit where it’s due.
I was able to learn what I needed to know by watching a number of free videos by McEwen and other content creators, then diving in to muck up a few jobs. However, others may benefit from more detailed instruction. I’ve heard nothing but good things about McEwen’s subscription-based tutorials, so you may decide they are a good investment based upon your needs.
I started my journey by purchasing a small library worth of books on enameling. I used the ratings on Amazon to determine which books were likely the best value for the money spent. Once I had learned all I could from the books, I then watched videos on YouTube and Vimeo until I was blurry-eyed. Finally, I dove in and began accumulating my own personal collection of mistakes. I eventually reached the point where I’d made enough mistakes to gain confidence and start consistently producing successful results.
Enamel is not cheap! I started off by purchasing the sample sets from Thompson Enamel, both opaque and transparent. For those unfamiliar, these consist of small zipper bags containing approximately a tablespoon of enamel, one bag per color. I used these to make test strips. You can find plenty of videos online that will teach you how this is done. Again, I found that videos by Sandra McEwen were the most useful to me.
I made samples for each of the permutations I planned to use in my studio. These included enamel over bare metal, over a transparent flux coat, over an opaque base coat, over silver foil, and over gold foil. I made a set of each of these permutations upon pure copper, then upon sterling, and finally upon fine silver. I even made samples of guilloche, first engraving a geometric pattern into the metal and then applying a thin coat of transparent enamel over it to see what the finished product would look like. It took a month’s worth of weekends to complete this project, but it paid dividends that just keep on giving.
I learned a lot about enameling just from creating these test strips. I used them to select the colors I wanted to use for my work, then purchased a small container of each. I then began attempting to create enameled jewelry.
In the beginning I used a Mapp gas torch to fire the enamel. I placed the work upon a fire brick and fired the enamel from above, playing the flame directly upon the enamel. This resulted in the flame blowing enamel off the work, my first valuable lesson learned via screw-up! I then placed the work on a metal trivet, placed the trivet upon a wire screen, and placed the screen upon a tripod of the type used in a lab to heat glassware above a bunsen or alcohol burner. This allowed me to fire work from underneath so as not to disturb the layer of enamel on top. This approach works surprisingly well and I made quite a few pieces of salable jewelry this way. I discovered that a torch on an extension hose attached to the Mapp gas bottle allowed me to leave the bottle on a stand on the floor and mount the torch under the tripod so I could work hands-free. This convenience enabled me to do such production work as enameling fancy custom-made chain one link at a time in rapid-fire sequence.
But my personal preference in jewelry design is Art Nouveau style pieces inspired by the designs of René Lalique, Georges Fouquet, Henri Vever, Philippe Wolfers, and Lucian Gaillard. If I wanted to begin producing heirloom quality Art Nouveau style jewelry, I would have to learn to produce Plique-à-jour style enamel.
Unfortunately, all attempts to produce Plique-à-jour with a torch ended in disaster. This style incorporates enamel that is wet packed into the openings in a pierced metal base, so there’s no enclosed cloison/cell to keep the enamel from slumping out of the opening when fired. I tried many different jury-rigged contrivances to keep the enamel in place, but it was all in vain.
I eventually gave up on it as a lost cause and tried using a Paragon kiln I’d purchased ten years earlier to heat treat metal. The kiln worked, but I could no longer watch the enamel as it progressed through the various stages during firing. I was forced to use a timer on my phone as a stopwatch to time the firing. This produced success most of the time, but was not nearly as consistent as the results I could produce by observing the transitions during torch firing. Some enamels/colors require more time, others less. It was just too much of a tedious pain to do trial runs and record the correct firing time for each enamel to produce a chart, then refer to this chart every time I fired a piece.
I called Paragon for advise. They sold me a new door with a window to replace the existing solid door. It was a simple bolt-on upgrade and the result was night and day improvement. I’m now again able to watch the enamel progress through the transitions just as I used to do while torch firing. This has pushed my success rate near a very consistent 100%.
But of course, the learning process continues. As you read in an earlier post, I recently discovered through bitter experience that I need to use Eutectic solder to join pieces that will be enameled.
Please feel free to ask questions and I will do my best to answer them. If I don’t know the answer, I will attempt to steer you to a reference that can…
jsfandskh,
Thanks for taking time to reply! I found value in your technical contribution to the conversation.
Don’t be too quick to write off jewelers as being disinterested in the technical stuff. Many are very bright, very curious, and very well-educated people much like yourself.
As for Eutectic solder resulting in a color mismatch, one can easily compensate by maintaining good discipline to produce tight joints, then using files and/or abrasives to clean up after soldering. As you pointed out, this is completely unnecessary when one will be covering the joint with opaque enamel or foil – one can leave the discoloration as-is because it will be completely hidden.
Be careful about moving off the Eutectic by adding more silver. The increase in the liquidus point may remain well below that of either metal, but one must also remain below the fusing temperature of the enamel. That’s already just ten degrees F under typical formulations of Eutectic silver solder, so if not very careful you could end up discovering the hard way that your project collapses in the kiln during enamel firing.
My formal education was in Electrical Engineering and my first career was as an RF engineer specializing in antenna design. As a result, I’m very familiar with the eutectic characteristics of the old lead-tin alloy solders used for electronics. Lead has properties that made it extremely useful for enhancing a number of manufacturing processes. Vitreous enamels were also once formulated with lead due to similar process improvements. But lead is toxic, so leaded enamels are now banned for jewelry use in most countries, as are lead-bearing solders.
Like you, I found the phase diagrams useful while researching this topic. The first time I tried soldering with Eutectic solder I was confounded by the fact there is no gradual transition from solid to liquid, unlike traditional zinc-bearing silver solders. Then I looked at the phase diagrams, which crystallize the concepts of bimetallic alloys with a visual aid to understanding.
Happy enameling!
I also took inspiration from art nouveau. I did fabrication with mixed metals- silver, copper, gold and brass. Using mixed metals is difficult… it makes its own solder close to the fusion temperature… a process of trial and error… ruining stuff is the price of gaining some knowledge, but still very worth it… we all learn best from our mistakes. Taking it to the next step then becomes possible. Best wishes to all and to all best outcomes…