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[ Alloys ] [ J-7 ] [ Technical Guide]


  Properties
Category Crown & Bridge
Nobility Noble
Type Type III
Melting Range 1680°F to 1810°F
Density 10.1 g/cm³
Hardness 235 HV
Tensile Elongation 20%
Tensile Yield Strength 57,700 psi
Ultimate Tensile Strength 75,400 psi
Chemistry
Silver 59.5% Palladium 25%
Copper 14% Zinc 1.5%
Ruthenium 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.
Investment
 Gypsum or phosphate bonded investment.
Burnout
 900°F (480°C) to 1200°F (650°C).
Melting / Casting
One extra wind of the casting arm is required (3-4 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 1900°F (1040°C).
Bench cool to a dull red before water quenching.
Finishing and Polishing
 Use standard techniques.
Soldering
 Recommended Solder: 1400 Solder
Flux-Brown Fluoride