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[ Alloys ] [ J-IV ] [ Technical Guide]


  Properties
Category Crown & Bridge
Nobility High Noble
Type Type IV
Melting Range 1680°F to 1805°F
Density 14.5 g/cm3
Grain Size 30 microns
Hardness
  Hardened
  Softened
 
250 HV
185 HV
Tensile Elongation
  Hardened
  Softened
 
20%
30%
Yield Strength
  Hardened
  Softened
 
90,400 psi
85,000 psi
Ultimate Tensile Strength
  Hardened
  Softened
 
109,500 psi
102,000 psi
Chemistry
Gold 68% Copper 12.5%
Silver 11% Palladium 6%
Platinum 1% 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.
Use of a refractory model is recommended for partial dentures.
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-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 obtain the hardened condition.
Water quench from a dull red heat to obtain the softened condition.
Finishing and Polishing
 Use standard techniques.
Soldering
 Recommended Solder: 615 Solder
Flux-Brown Fluoride