Casting of silver causes a fire scale to form on the silver because of the high heat and exposure to air. When a silver piece is released fresh out of the investment material, it is very dark and scally. The first step is to wash and scrub off all the investment, then to drop the piece into the pickle bath.
I use an organic acid solution that it heated to slightly steaming temperature in a small crock pot. This is the pickle. The piece, depending on solution temperature, may stay there for about a half hour or so.
I usually am able to scrub off the blackness about half way through, then a bit more time in the pickle the silver will be the snow white as seen here.
This is actually the pure color of silver before it is polished. The slight pink seen on the metal is a blush of the copper that the acid draws out. Sterling is 7.5% copper to make it hard and more durable than pure silver.
After this stage, the sprue is cut off and filed smooth untill evidence of the sprue location no longer exists. Then comes all the polishing and burnishing to the final finish.
Some pieces have an applied chemical darkening to add contrast.
So after this point is where all the working with silver really begins. I love it!
Silver purchase prices have risen. It was in the ~$14/T oz. range and is now near the ~$18/T oz. area, for casting grains total cost delivered in my studio. Market price is always lower than purchase price. I just restocked with 10 ounces as this is the lowest cost break point weight for Sterling. But it also means I will have to adjust my finished goods pricing to follow the market. This is about a 20% increase in the price.
I have paid over $22.00 dollars per Troy ounce less than two years ago. The price varies constantly. For me it is what it is and the cost of my work will vary with my supply. I don’t fine tune it too closely with the market as that fluctuates every day. I use a fair estimate and definitely cover the cost of a new stock material purchase. 60¢ a gram is a good round actual cost estimate.
Small silver cost changes right now are not too critical when cost is lower. Silver is not presently the major expense against operating supplies and expenses and reasonable (but pitiful J ) labor earnings. A more expensive metal like gold is opposite. A few grams at $28/gram (14k) can radically change the cost of a project.
The total value of silver or any precious metal jewelry is not all in the cost of the metal, but it helps. Sometimes a lot.
I have ordered a sculpting product called Cx5 and Cx5s made by Adam Beane Industries (ABI). I have been aware of it for several years but had no motivation to try it. Now I am wondering if it will be a suitable media for doing the small carvings I have been doing in wax.
The material is heat sensitive in relation to it firmness or actually hardness. It can be worked much the same as wax but also has characteristics of clay. It seems to be a product that is a bit out of the mainstream for hard core sculpters. But that could be because it is more of a cross breed between clay sculpting material and hard wax carving. Any change in work habits are hard for hardcore artist, used to their standard processes.
In any case I have ordered some and will give it a workout. I submitted a question to the maker of this product asking if it could work directly in lost wax casting replacing the burnout wax. (NO REPLY) Cx5 will be of less interest to me if I have to do an intermediate step of creating a wax master for the burn out.
I have an adult son and daughter that like to work with clay so I asked them come over when it arrives and try a sample. It's claimed to be a great product for making masters for resin casting. Since I like to do that as well as my silver work, perhaps he and I can do some larger pieces than I normally do in lost wax silver casting. It is also suitable for any large scale metal casting too.
After 19 days I finally received my shipment of Cx5 and Cx5s. No comment from ABI for the delay and in fact the ABI website had listed my order as unpaid for 15 days. That concerned me so I used the PayPal customer support system and communicated my concern to ABI. They shipped the product nearly immediately.
Cx5 is much harder material than Castilene and I am excited to give it that workout I mentioned above.
I will review the product over in Ramblin' Dan's Workshop and certainly display any creations here in Dimensional Art Org.
These are two of the Celtic Three Dog pendants I recently cast in sterling silver. The background was darkened using Midas “Black Max” solution. A wax master for one of them is shown in the previous post. I made two pendants (using two wax master carvings) in a single pour in one flask.
I am confident now that I can make just about anything with lost wax casting. I have the process working very well and I have a good repeatable routine. I’m looking now for new designs and objects (subject matter) for casting.
I think I am going to get committed because of this lost wax mania. Mania is a mental illness marked by periods of great excitement, euphoria, delusions, and over activity. I have all the symptoms. Maybe it is a bad thing. To me it seems like a good thing and I really enjoy the “high”. Better than drugs I assume.
I often studied and thought of doing castings. Maybe because I was born and raised in a steel making town. Pour molten iron into a mold and out comes a new iron part. And it could be done over and over again.
I was first exposed to lost wax casting when I was a pre-teen and reading and studying all the model train magazines and information I could find. I was not so interested in running the trains but I sure loved reading and studying all the scratch building projects. Many of the small detailed metal parts were reported as being made by the lost wax casting process.
There must have been a lot of folks doing it as a cottage business to the model railroad market and maybe an offspring of the jewelry lost wax casting. The model parts were usually brass or white metal. I am sure it was done on spin casting centripetal machinery and perhaps something like plastic injection molding system.
I built some models from rather large white metal or zinc castings where I had to file off the flash, but I am not sure of the exact casting process.
On a small scale, how I am casting today could be used. But what I do is not anything near commercial production quantity. It’s quite an investment if all I wanted to do was a few model train parts.
I am in my comfort zone right now, just casting the pretty things I like to make. I really like working with the wax with both the CNC and manual carving. No subject or design is off limits, but it does have to fit within my tools and abilities.
Silver is my metal of choice right now, but I have experimented with brass casting. Just depends on what I am making. So much to try and do, it could drive me crazy…