When using sheet provided by Stuller, always anneal prior to cold working since we supply our sheet at three quarter hard.

Selecting a Metal:

• Best to use alloys formulated for wrought products. Though most casting alloys can be rolled they may behave more brittle due to deoxidizers that are added.
• Nickel white alloys with high zinc content are prone to fire cracking.
• Use alloys designed for the karat you desire. Ratio of elemental additions vary based on karatage.
• Be sure the properties of the alloy match what you want to manufacture. 14KY with elevated silver is heat-treatable and work harden faster. 18KY with elevated copper is heat treatable and work harden faster.

Pouring the ingot:

• Clean all crucibles and molds before starting.
• Always preheat mold to 300 degrees Fahrenheit prior to pouring.
• Always preheat crucible prior to melting.
• Flux and/or protective gas should always be used on top of the melt (boric acid and/or natural gas flame are sufficient).
• Don't overheat the metal (150 - 225 degrees Fahrenheit over the melting point is sufficient).
• Pour quickly initially, then slow the pour as the end of the melt approaches.
• Check compatibility of the metals being melted with crucibles, stir rods, and molds. (Ideally graphite should be avoided when using nickel bearing alloys.)
• Quench ingot in water to achieve softest cast state. Yellow golds can generally be done almost immediately. White golds and solders should be quenched immediately after the red color has disappeared.

Rolling of Metals:

• Ingots should have shrinkage pipe trimmed prior to rolling.
• Do not anneal ingot until significant reduction is achieved through cold working. (White gold needs 50% to reduce fire cracking likelihood.)
• Even out stresses by flipping the ingot while rolling.
• Use multiple passes at the same setting on mill head to flatten sheet.
• Reduction of the load on the mill can be achieved by using a light oil on the rollers while rolling. (Lint and dust from billet are also washed away.)
• Avoid light passes on thick material (thicker than 0.125"). Light passes can cause billet to bow, or, even worse, split down the center due to uneven stress.
• Sharp corners on feed side of sheet should be trimmed to help preserve rollers.
• If cracks do happen, drilling a hole in the tip of the crack will help prevent it from continuing.

Rolling Mill Maintenance:

• Keeping the pins on your rolling mill in top shape is very important. Rusty or pitted pins will not give you a high-quality piece of stock of plate.
• To keep the pins clean and oiled, install cloth wrapped dishwashing-type sponges at the top of your top roller, and one under the bottom roller.
• Cut the sponge so it fits snugly against the sides of the mill and applies light pressure on the rolling pins, the bottom sponge should fit the same as the top one. Use lint free cloth and wrap the sponge. Some pressure is required to keep the pads from coming out of place when the pins are turned.
• On larger mills, a bracket made from a clothes hanger or brass rod may be needed to hold the sponge in place.
• Apply enough light machine oil to saturate both sponges. As the mill is being used, a light coat of oil is applied to the pins which aids in the rolling of stock and plate. The sponges also work as pin cleaners, so you don't have to worry about a piece of gold being pressed into the plate or stock being rolled.
• When you are finished with the mill, a light coat of oil will be on the pins to keep them from rusting.

Furnace Annnealing:

• Do not anneal ingot until significant reduction is achieved through cold work.
• A furnace with a controlled non-oxygen atmosphere such as cracked ammonia will retard discoloration due to surface oxidation. If using a furnace without a controlled atmosphere, coat the piece with a good commercial flux or a mixture of alcohol and boric acid.
• Most yellow golds require about 10 minutes at 1200 degrees Fahrenheit to fully anneal. Excess time and temperature may result in orange peeling. Quenching in water can be done immediately.
• Most white golds require about 10 minutes at 1350 degrees Fahrenheit to fully anneal. Excess time and temperature may result in orange peeling. Quench immediately after red color has disappeared.

Torch Annnealing (softening):

• Though adequate softening can be achieved with the described process, heating for short times usually result in partial anneal.
• Coat the piece with a good commercial flux or a mixture of alcohol and boric acid. • Yellow golds are heated to low red color, then quenched in water or pickle solution. • White golds are heated to low red color. Quench in water or pickle solution immediately after the red color is gone.

Stress Relieving Anneal:

• To greatly reduce the risk of stress-corrosion cracking, heat material to 600 degrees Fahrenheit for about thirty minutes and cool slowly before final polishing.

• Specific alloys are required for age hardening, check with vendor.
• Heat to 1250 degrees Fahrenheit for thirty minutes. Quench immediately.
• Reheat to 600 degrees Fahrenheit for one to two hours. Air cool or water quench.