I have always use an air/propane turbo torch to melt silver, brass, bronze for my investment castings. The torch works fine for small amounts in the 20–30-gram range. I have melted as high as 70 grams, but the process gets much more difficult.
The open puddle of liquid metal loses heat rapidly. I must follow the melt (in a crucible) from my heating area to the mold flask with the torch constantly “playing” on the melt puddle. It’s a two-hand operation with the torch in my left hand and the crucible (clamped in holding-tongs) in my right hand.
The pour is single handed into the top of the mold flask. A growing issue is my (PN) Peripheral Neuropathy sometimes gives me a bit of hand quiver if I do not consciously try to relax my right arm.
I like to do larger pours with larger projects. A few days ago I cast a 60 gram melt of silver for a small bell. Before that I did a large ~200g melt of brass for a solid brass gnome figure. Both jobs pushed my personal comfort limits for torch melting and pouring.
Casting 1700-2000 degree metal is nothing that one should feel difficult or uncomfortable performing.
I must be completely in control of the casting operation. The transfer process from the melt to the pour stage with heavier and larger volumes has begun to exceed my comfort zone.
I considered the melting furnace since day one. However, the volume of the metal for my jewelry work has typically been small. Nothing that a torch could not handle comfortably. Time and old age alter my comfort zones. Now is the time to stop considering and act. Ha!
RioGrande, my jewelry tool and materials supplier, offers several Italian made models of melting furnaces. However, the 1kg (gold melt) capacity furnace with a purchase cost of over $650 has always been a deterrent. The larger sizes are up to $950. A cost not justified for my needs.
Amazon has a huge selection of similar Chinese made melting furnaces. Some under $300. I choose a 1kg capacity furnace (shown) with a little higher wattage than others. I leave my selection reasons there as I am not making recommendations on brands and models. Reasonable cost was the major decision factor.
A closed chamber electric melting furnace with digital temperature control provides a far improved melt environment. Metal is not overheated and far fewer contaminates are introduced to the melt. The crucible is graphite which adsorbs oxygen.
Pour timing is less critical as the metal remains liquid a bit longer between the melt and the actual pour. I can use two hands (if needed) between the melt furnace and the mold flask pour point.
I believe small single item castings will continue to be more practical using the torch melt system. It is quicker than heating a 1kg (about 500g for silver) capacity electric furnace for a 25-gram casting. A load that small is almost lost within the crucible.
I will understand the process method balance once I have a chance to use my new melt furnace. One thing I know for certain. I will be far more comfortable with larger loads with the furnace. Perhaps small loads will be no problem at all… just longer to melt than the torch.
Trying to think of a cool Christmas thyme project, the thought of colored glass enamel came to mind. Of course! Color is what is needed and missing in my silver work. I use a bit of black silver oxide on many of my pieces for definition. But there is a universe of color available.
The process in this project is called champlevé. I don’t carve the troughs for the color but rather use a lost wax silver casting with the recesses designed into the casting.
The vitreous enamel pundits say glass enamel can’t be done with Sterling silver (because of the copper) but as can be seen, it’s all just knowing how.
The process is to pickle the silver and create a barrier layer of pure silver on the surface. I may explain the process in some future post. It’s not magic, just a technique.
There is a similar process to champlevé called basse-taille. The difference is basse-taille used transparent enamel so features and designs under the enamel can be seen. That will be on my agenda for some future project.
This is a Christmas season pendant, so I picked a poinsettia blossom as my subject. I found a general outline drawing of a poinsettia so I would get the shape correct. It was not in a useable format for designing a Champlevé but got me started in my own design.
The pendant was created in Vectric Aspire (V10) as I am very comfortable with designing with this software.
Since Aspire can output .stl files, after I completed the design, I used one of my 3D printers to create a plastic prototype. The real output was to a g-code file for my Taig CNC mill.
I have one of my Taig mills dedicated to carving wax. I modified this mill by adding a 20.000 rpm water cooled spindle and a fourth axis (A) for rotary milling projects. (jewelry rings).
I machined two wax masters of the poinsettia pendant design and cast them in sterling silver using the lost wax casting method.
The resultant casting was cleaned and prepped for the champlevé process. Four firings (layers) were required to fill the recesses.
After the enameling was complete, the silver was again brought up to a full mirror like finish, through several stages of polishing.
Last step was the addition of the bails.
I think they look quite good and now I am planning to make a few more duplicates, then move on to other glass enameling projects.
These are my first attempts at glass enameling on Sterling Silver. I think they came out well and I am excited to do much more of this work. My efforts should only get better with practice.
These are not the only pieces. I made at least 10 of the skating Pegasus and three of the Rose Hearts.
Like lost wax casting there is no certainty on how each piece will come out of the heat. Temperatures for firing the glass are 1450 F. Success rate is very high but there is always that chance of the unexpected.
I am considering a slightly new direction with my metal working / art adventures. I would like to add some color to my work. Silver with some occasional black tarnish doesn’t add much excitement to silver jewelry. I could start to add colored gems. That would be a major next step.
There is another option I have been mentally exploring called glass enameling. First thought might be the kind of paint that comes out of a rattle can (spray can) made by a brand name, Rust-Oleum. Nope, not that kind.
The enameling I am considering is fusing glass particles to a metal substrate with the use of high heat. Hot enough, 1450 degrees, to melt the colored glass and fuse it to the metal. It’s been done for centuries and one of the best known processes are from France called Cloisonné and Champlevé. Another process called Basse-taille offers a similar result but uses only translucent enamels to show the features of the metal underneath the coating.
It was also a practice in China and other countries in the far east. The example shown above is from the Ming Dynasty. Examples can also be found in Europe, the near east and many other world cultures.
All processes fuse colored glass enamel into cells created in the base metal. The cells are created with metal wire frames in the Cloisonné method and by carved or formed recesses with the Champlevé. There are many variations as in any type of art.
The results can be very stunning and beautiful. It is a creative process with a lot of controlled heating required. Just the kind of challenge to keep it rare and collectable.
There is an alternative chemical epoxy cold process method that can be used to create a similar look, but I think the old school firing is my preference. It’s the heat of the fire that attracts me to lost wax casting… and to this glass enameling process.
I have a little project I am going to try. If it works out the way I imagine, I’ll certainly exhibit the results and it may be the start of a unique product line of glass enameling.
Making tools can be a form of dimensional art. I like the look and the feel of any good hand tool. When it is a tool that has been well made with your own hands it has the special feel or spirit about it.
Here are a couple of prototype "Impression" stamp tools I made in just a few hours after gathering the materials. The handles were purchased as I am creative only so far. Ha!
My daughter asked me to make these for use in her glass bead work. She is another creative family member. In fact the whole family has artistic skills we should exploit more than we presently do.
These are prototypes and I am considering making these in batches if other people get interested. The head designs are limited only by size and imagination. As seen what I call "inies" and "outies" can be formed. If I can draw it I can make it.
The long handles are required because the glass work is very hot, but the result is very similar to pressing a seal into sealing wax or even cookie dough. Hmm... I can make those too...
Glass enameling is a process of using high temperature to fuse glass onto the surface of metal.