Docs Casting Plaster

A few images shot at our shop on GIA open house day. Once a year we have GIA students in through their alumni programs. The top picture shows the actual smelting of pure gold. Next is a shot of the gold being mixed with the alloy to make it into 18kt white gold. The next shot is that gold being vacuum cast.  At bottom the raw 18kt white gold castings. The advantage of hydrogen for silver, gold and platinum is incredibly clean heat. 5000+ degrees Fahrenheit. Since hydrogen is an element as is oxygen, there is no carbon in the combustion as with natural gas, propane and acetylene. This illustrates how clean our environment could be if our primary fuel were hydrogen. The byproduct is pure water. One great precious metal that responds badly to hydrogen is palladium and palladium white gold.

For those most difficult resin Cad-Cam models... If you are using this material to simply overcome the defects that you encounter from the use of carving or RP waxes, you can just as well use a normal jewelry burnout cycle in the same oven as your normal daily production flasks. Method B: (Smaller flasks or small flask-less castings) Note: Casting flask-less is ideal with this type of material · Program your oven controller for a ramp rate from 4 degrees per minute to a maximum of 10 degrees per minute. This investment material is very resistant to shock so your ramp up speed can be faster than with gypsum-bonded investment. · About 1 hour after investing, put the flask into an oven that is preheated to about 300 o F (150 o C), with the wax button facing down. · Ramp directly up to your top burnout temperature of about 1350 o F - 1600 o F, depending on the metal you are burning out. For photopolymer...