Manufacturing Cremation Urns--An Overview of Manufacturing Processes
There are many different types of cremation urns and there are also different processes used to manufacture each type. This section contains an overview of each, including advantages and disadvantages.
Fabricated or Wrought
This is a construction method using shearing, bending, welding, forming, or hammering to produce a bronze, stainless steel, or copper urn. It's a cost-effective method of manufacturing due to the fact that it's not as labor intensive as other methods.
Another advantage to this method is that these urns are easily personalized due to their smooth finish. The only disadvantage is that they're available only in a satin finish.
This method of manufacturing cremation urns is used to make a round shape starting with a flat sheet material in either bronze, stainless steel, copper, or pewter. The flat material, while spinning on a lathe, is forced over a collapsible mandrel that's the shape of the final product.
This is done at very high pressures of 3,000 to 6,000 pounds per square inch (PSI). This is a cost-effective way to make a round part from a flat sheet of metal, and again, these urns are easily personalized due to their satin finish.
Advantages of spinning: cost effective, urns are easily personalized.
Disadvantages of spinning: urns are available only in a satin finish.
This is the process of reducing solid bronze (ingot) to a liquid state and pouring the liquid bronze into a mold. The mold is made from sand that has been compressed at 20,000 PSI.
The pouring temperature of the molten bronze is 2,300 Fahrenheit. This is an extremely labor-intensive process and therefore costly, however, very detailed and intricate designs can be achieved using this method.
Advantages of casting: highly detailed.
Disadvantages of casting: extremely labor-intensive, and costly process.
This is a variation of the sand casting process described above. The artist starts by making the original sculpture from clay. A rubber mold is then made from the original artwork. A transitional wax sculpture is made from the rubber mold. The wax casting is removed from the rubber mold and retouched.
The wax model is equipped with rods, gates, and vents to allow the passage of molten bronze into the mold. The wax model is then coated with a liquid ceramic. The entire piece is placed in an autoclave.
The wax melts out of the shell (thus the term "lost wax"). This shell is the final mold into which the bronze will be poured. After the bronze has been poured into the form and allowed to cool, the ceramic shell is broken away from the bronze sculpture.
The sculpture is sandblasted to remove any remaining ceramic. The gates and sprues are cut off and all areas are blended together to make the casting look like the original artwork. The bronze sculpture is then treated with chemicals and heat to give it color. The artwork receives a final coating of wax, which becomes a permanent part of the structure.
It's interesting to note that this is the same process used by famous artists such as Frederic Remington to produce their works of art.
Advantages of lost wax: highly detailed urns are possible.
Disadvantages of lost wax: extremely labor intensive and costly process.
In cloisonné manufacturing, the shape of the brass core is formed with a gentle hammering. An intricate design is then formed using copper wire netting, and colored enamel is bonded to the core and then fired in a kiln.
The third step is repeated several times to enhance the beauty and durability of the design. The urn is gently hand-scored and polished for a smooth surface. The urn is then gilded to protect the brass from rust and to create a bright, shining finish.