Nov
04
metal working
Kent Kelin asked:


Bronze Casting has been practiced for centuries. Many civilizations have used this alloy for weapons, sculptures, and general pieces of hardware. The popular way to cast bronze is the Lost Wax Casting process which was first used sometime in the 3000 BC near ancient Sumeria. The Lost Wax process is still used to this day and its modern equivalent Investment Casting is very popular with jewelry makers.

Bronze is the preferred alloy for metal working artists as it’s relatively easy to work with and resistant to corrosion. The properties of bronze tend to be stronger than most other alloys, except of course for steel, and lends itself easily to the molding and casting process. Many small foundries like the kind that can be found in a backyard or workshop find that bronze is a great material to work with and with a melting point of 1,700 Fahrenheit or about 925 Celsius many homemade furnaces are able to melt down the bronze quickly and efficiently.

Many modern day artists create their own furnaces with the metal casting in mind. These metal casters employ the Lost Wax Casting method which proves to be the best when dealing with the alloy. The Lost Wax Casting is making an original of the sculpture from wax and then creating a mold using this original. Often times the original is lost during the mold making process so keep that in mind if you want to hang on to the original for whatever reason. Molten wax is poured into the mold which is chased or smoothed of imperfections. During this point, any other pieces are attached and small wax tubes are placed into the piece. These tubes will be how the molten bronze is going to travel into the piece replacing wax with the alloy. When this is complete the artist will create a ceramic shell around the wax model. This shell will help form the molten bronze which will melt the wax. When the molten bronze is poured the bronze takes place of the wax. Afterwards, the artist will ***** the shell and reveal the bronze piece. This method allows the transfer of very exact detail from the wax to the bronze.

Patina is added to the figure at the artist’s discretion. The Patina is a chemical that when applied to bronze creates colors and makes the bronze take an aged look. The Patrina compounds used depends on the type of color desired. Ferric Nitrate will make the bronze take on a red or brown color while Sulphurated Potash will make black and Cupric Nitrate will create blue and green. Modern day artists choose to go with a very high polished bronze instead of using these compounds. This step depends solely on the artist’s taste and the look they are going for.

Bronze casting will remain a popular medium until another alloy is developed that exhibits properties that are easier to manage and are more resistant to corrosion. Casting the alloy is easily done so metal casters that want to experiment are encouraged to do so. Making anything from small figurines, large sculptures, and even cabinet handles can be accomplished with the use of bronze. The only limitations in bronze casting are with the caster himself.

metal working hobby
Kent Kelin asked:


Metal casting supplies can run the gamut of cheap to expensive. Home foundries tend to use supplies that are not too costly or that can be found close at hand. After all, home metal casting is usually a hobby and many get into this hobby since they need a cheaper source of parts and pieces that are either far too expensive or just impossible to find. This reason is actually what draws many people to metal casting in the first place. Given this, metal casting supplies used in smaller backyard foundries are generally cheap and made of items that are available in the garage or can be found at home improvement stores. There are several online resources and stores that offer supplies specially made for metal casting and if you have the money and are unable to create your own, it is encouraged that you purchase already made supplies.

The metal casting supplies you will need ultimately depend upon the type of work you plan to do. If you plan to use lost foam casting you will not need any wax and in that same thought you won’t need any foam if you are going to use lost wax casting. The furnace type is also a consideration. Cupola furnaces do not use crucibles. A crucible is where you place the metal which will then pool and collect inside. So it is important to decide what kind of casting process and what kind of furnace that will be used before you rush out to buy supplies.

As for the supplies this will include the fuel source. Fuels sources can range from wood to propane. Metals with a higher melting point will need propane while wood can be used to melt pewter and possibly aluminum. Most home foundries will use propane since it produces a high temperature and is easily available. 

Many of the metal casting processes use sand as a way to create molds and help secure those molds during the pouring. The type of sand used does not have to necessarily be specially formulated. Sand has been used in casting since ancient times so it only makes sense that most sand types can be used. Many hobbyists will even use playground sand to meet their needs. Now, there is a special type of sand used in casting called green sand. Green sand packs well and is able to hold its shape far better then common sand. For processes like lost wax you will need to find a healthy supply of wax since many of the steps involve the creation of wax models and molds. The good thing about this process is that the wax can be reused time and time again. Supplies for lost foam can be found in home improvement stores since foam insulation is suitable to use. You will not be able to reuse the foam but luckily, the foam is cheap.

Perhaps the most important casting supply is the metal itself. The metal used in casting varies due to need. Aluminum is a common alloy used in casting for a number of reasons, chief among them is availability. Aluminum soda cans are crushed and melted and proves to a good source of the metal. Many casters will find scrap metal in junk yards which tend to be a good source for brass, bronze, and iron. There are places to buy metals in ingots if you want a purer metal to work with.

Metal casting supplies often dictate what the caster can and can not do. Keep this in mind as you plan your next project as adjustments might be needed to your plan.