DENT1014: The 17 Laws of Casting

The pattern sprue former should always be attached to the thinnest cross section of the wax pattern.

• a) True

• b) False

Alloy should flow from areas of greater volume to areas of lesser volume (ie.margins)

• a) True

• b) False

If the wax patterns are not positioned in cold zone, what penalty could occur?

• a) short margins

• b) cold shuts

• c) incomplete castings

• d) porosity

In order to compensate for metal/alloy shrinkage that occurs during solidification...

• a) reservoir must have sufficient molten alloy

• b) reservoir must have less molten metal

• c) reservoir must have no molten metal

• d) none of the above

A button must not be casted when using a runner bar.

• a) True

• b) False

When casting, turbulence must be avoided at all times.

• a) True

• b) False

To prevent bubbles from being trapped between investment and patterns a wetting agent (ie.picosilk) is used to decrease surface tension and increase wettability of pattern.

• a) True

• b) False

The water and investment liquid measurement for high noble/noble alloy (precious metal) is...

• a) 11.5mL investment liquid/ 11.5mL water

• b) 11mL investment liquid/ 12mL of water

• c) 16mL investment liquid/ 7mL of water

• d) 15mL investment liquid/ 8mL water

A bowl and spatula should be used to mix investment in order to avoid bubbles.

• a) True

• b) False

Investment should be allowed to set completely before placing in the burnout oven. Be sure to bench set your ring for...

• a) 15 mins

• c) 25 mins

• c) 30 mins

• d) 45 mins