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[ Alloys ] [ SL-40 ] [ Technical Guide]


  Properties
Category Crown & Bridge
Nobility Noble
Type Type III
Melting Range 1565°F to 1750°F
Coef. of Thermal Expansion
   from 25°C to 500°C
   from 25°C to 600°C
14.2x10-6K-1
14.5x10-6K-1
Density 12.7 g/cm3
Hardness 140 HV
Tensile Elongation 18%
Tensile Yield Strength 71,200 psi
Ultimate Tensile Strength 85,800 psi
Chemistry
Silver 45% Gold 40%
Copper 8.5% Palladium 5%
Zinc 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-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 1850°F (1010°C).
Bench cool to a dull red before water quenching.
Finishing and Polishing
 Use standard techniques.
Soldering
 Recommended Solder: 585 Solder
Flux-Brown Fluoride