Alfa Ceramic 90 – Användningsinstruktioner

Wax-up: Minimum thickness of wax should be no less than 0.3mm. for single units and 0.4mm. 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 . Follow the manufacturer's instructions. No more than 1/4" (6 mm) of investment should cover highest point of wax pattern. Ring should be burned out at 1400° F/760°C for a minimum of 45 minutes or according to manufacturer’s recommended time. Place the ring(s) in a room temperature oven and raise the temperature to 780 °C / 1440 °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 = 18.8 g/cm3 * (Wax Weight). For reusing casted alloys use only clean buttons and at least 30 percent new alloy.

Casting: Centrifugal type casting machines should be wound 3 1/2 to 4 turns. No asbestos or flux should be used in crucible. 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. The metal should be heated to approximately 2300°F/1300°C before casting. 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 aluminum 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 aluminum oxide disc or red stone. Do not use heatless stones or steam cleaners. After grinding, metal should be cleaned in distilled water in ultrasonic cleaner. If the work was waxed to finish then no grinding is required.

Degas at 980°C/1800°F for 2 minutes in air and 2 minutes in vacuum, for a total of 4 minutes. Gold coating agents are not essential but if used, can be applied and fired in placed of degassing. After this step, care should be taken to avoid contamination of 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: ThorL 700, Thor L 820

Hardening: Heat Treat for app. 30 min. at 420°C


Alldental Q & Co. AB                    CE 0413
Box 92001
120 06 STOCKHOLM
Sweden
Tel. +46-(0)8-694 80 25
Fax +46-(0)8-694 80 26