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[ Alloys ] [ J-3 ] [ Technical Guide]


  Properties
Category Crown & Bridge
Nobility Noble
Type Type IV
Melting Range 1545°F to 1625°F
Density 12.9 g/cm3
Hardness 230 HV
Tensile Elongation 13%
Tensile Yield Strength 91,500 psi
Ultimate Tensile Strength 100,000 psi
Chemistry
Gold 50% Silver 29.5%
Copper 15.2% Palladium 4%
Zinc less than 1% Indium less than 1%
Iridium less than 1%    

Waxing / Spruing
Sprue to the bulkiest section.
Sprue diameter should be equal to the thickness of the bulkiest section.
Sprues longer than 3/8" should have a reservoir 1/16" from pattern.
Patterns should be no farther than 1/4" from top of investment.
Use direct method for single units and small castings.
Use indirect method for bridges and larger castings.
Investment
 Gypsum or phosphate bonded investment.
Burnout
 900°F (480°C) to 1200°F (650°C).
Melting / Casting
No extra winds of the casting arm are required (2-3 winds typical)
Multi-or single-orifice torch: 5 psi fuel and 10 psi oxygen.
The alloy will fully puddle and form a ball before it is ready to cast. DO NOT OVERHEAT.
Cast at around 1725°F (940°C).
Bench cool to a dull red before water quenching.
Finishing and Polishing
 Use standard techniques.
Soldering
 Recommended Solder: 585 Solder
Flux-Brown Fluoride