Alfa Ceramic 17 – Product Specification Sheet
Wax-up: Minimum thickness of wax should be no less than 0.3 mm. for single units and 0.4 mm. for bridges and multi-units. Sprues should be no smaller than 8-10 gauge, (3.3-2.6 mm diameter) and no longer than 1/4" (6 mm) with adequate reservoirs.
Investing and Burnout: Recommended Investment: Phosphate Bonded (Carbon free). Follow the manufacturer’s instructions. No more than 1/4" (6 mm) of investment should cover highest point of wax pattern. Place the ring(s) in a room temperature oven and raise the temperature to 800 °C/1470 °F for 1 hour plus 10 minutes for each additional ring. If you are using a rapid fire investment, follow the manufacturer's instructions.
Alloy Quantity: Required Alloy Quantity = 19.1 g/cm3 * (Wax Weight). For reusing casted alloys use only clean buttons and at least 35 percent new alloy.
Casting: Centrifugal type casting machines should be wound 3 ½ to 4 full turns. Use a quartz crucible that has not been previously used for a different alloy. Avoid graphite crucibles or the use of carbon, asbestos or flux should be in contact with the metal during melting.
A hot gas-oxygen torch with a multi-orifice tip should be used with the inner cone of the flame at least 1/2 to 3/4 inches long to avoid excessive oxidation during melting. The fuel proportions should be one-part fuel to two-parts oxygen.
At the casting temperature, the metal appears like fluid and will vibrate if the casting machine arm is tapped gently. Every casting machine is different. The casting temperature may require adjustment based upon the alloy and the amount of metal being cast.
For cooling, allow the casting ring to cool to room temperature. DO NOT quench in water.
Cleaning and Finishing: The investment should be removed by sandblasting (50 micron aluminium oxide at two (2) bars of pressure (30psi)) and/or a chemical reagent. All traces of chemicals should be removed by rinsing in tap water followed by cleaning in distilled water in ultrasonic cleaner. All surfaces to which porcelain is to be applied should be rough ground with an aluminium oxide disc. Do not use heatless stones or steam cleaners.
Degas: at 1010°C/1850°F for 2 minutes in air and 2 minutes in vacuum, for a total of 4 minutes. After this step take particular caution to avoid contact between the metal surface and fingers or any foreign object that could leave a contaminant deposit on the surface.
Surface is then ready for application of opaque according to porcelain manufacturer’s instructions.
Presolder: Solder joints should be large (at least 5 mm²). Soldering gap about 0.05-0.2 mm. Invested units should be preheated and pressure blasted with 50 micron just before soldering.
Post Soldering (After Firing): Solder joints should be large (at least 5 mm²). Soldering gap approximately 0.05 - 0.2 mm. Cover ceramically-veneered units with wax before investing. Use: L 720
Alldental Q & Co. AB CE 0413
120 06 STOCKHOLM
Tel. +46-(0)8-694 80 25
Fax +46-(0)8-694 80 26