FAQ

Porosity is normally the result of:

1. Metal too hot during casting process
2. Improper spruing

There may be several potential reasons:

1. Not cleaning stone from colloid after breaking-out of flask
2. Not keeping colloid hydrated after breaking-out of flask and sitting in bucket waiting to be remelted.
3. Duplicator getting too hot.

Check temperature reading.

The bottom tank bearing should be examined for excessive wear each time hydrocolloid is replaced. The bearing should be changed annually to prevent excessive wear on stirrer shaft.

There are several causes for squeal in the spindle:

1. The tension on the belt. Belt may be too tight, there should be about 3/8 inch play in the belt when depressed.
2. Dirty Collet, clean the collet.
3. Collet out of adjustment, make adjustment on collet, may be gripping the mandrel too tightly.
4. Spindle may be worn out, return the spindle to manufacture for factory replacement of inner parts.
Check the video embedded within the Technical Sheet CLICK HERE

Use FlexStar finishing kit (item 24000P9) and finish with pumice and a rag wheel. Second, tripoli. For final buff, use Shining Star Hi-Shine (item 301) to get a nice glossy shine with minimal effort.

What is your oven temperature set at? (550 degrees) Have you checked to see that temperature is correct? Are you heating your flask? (room temperature) If these questions are all answered correctly-ask them how many sprues are you using and what is the diameter? If 3 sprues are being used-the material may be flowing in too quickly and this can also cause porosity. 2 sprues at approximately 6-7 mm in diameter are sufficient.

Is your cartridge sleeve being preheated for 15 minutes? Any subsequent injections 10 minutes. Is the crimped end toward the flask when injecting. Are you using the bronze disc? If doing all these things correctly and tube still will not pop, double check the oven temp and see if it is correct. If everything is still good-retighten the springs on top of the injector. These sometimes will loosen. As an additional measure-you can place a crisscross with a blade knife over the cap end of the tube to help it inject.

Make sure there was atleast 1 mm space underneath the necks of the teeth.

This is caused by heat. Either the temperature set too high-or being left too long in the oven will cause the color to change or lighten. The pigments are food-grade and will tend to "burn-out" if heated too long.

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POROSITY- Caused by heat. Do not pre-heat the flask. Make sure temperature is at 550 degrees and that only 2 sprues are being used. PSI should be at 90 lbs of pressure.

MATERIAL LOCKING AROUND PISTON- Make sure flask is not heated and times and temperatures are correct. Make sure air pressure is 90 PSI. Double check that cartridge sleeve is held completely vertical. If all these things are correct- we have some specially milled piston heads that can replace the piston heads normally used. It will make it easier to clean the material off-and may eliminate this from happening all together. Some labs have reported using the thin bronze disk with success.

Flexite is a trademark of Rapid Injection Systems

This can happen if the material is not melted completely. With this system, several cartridge sleeves are loaded into the oven and it may take longer for the material to melt. Try heating the cartridge sleeve at 14 minutes. As an additional measure-you can place a crisscross with a blade knife over the cap end of the tube to help it inject.

Seams or folds may be caused by:

1. Improper time and temperature, processing the material. Review processing times and temperatures for the oven, 15 minutes preheating the oven; 12 minutes heating the cartridge prior to injecting.
2. Oven temperature incorrect, should be 550 F (290 C) when heating the cartridge.
3. Separating material not completely dry. Make sure the separating medium is completely dry before closing the flask for injection.

The most likely problem is that the alloy was not hot enough.
Incorrect spruing

Porosity can be caused by several issues:
1. Metal is too hot when casting
2. Improper size sprues used
3. Investment particles flowing into the mold
4. Dirty crucible
5. Using lead on the refractory model
6. Debris in your wax or dipping pot-getting carried into the mold

See website for Nobilium partial denture technique. Look for Nobilium alloys, and then click on DFU (Directions for Use).

Rings may be cracking due to:

1. By passing low fire stage.
2. The rate of climb for low fire is too fast.
3. The low fire temperature may be too high.

1. The maximum temperature for the dehydration process is 450 degrees Fahrenheit.
2. Thermal expansion for most investments begins at 500 degrees Fahrenheit. If you are taking the investment to 450 degrees Fahrenheit make sure the oven is properly calibrated. Otherwise, you will wax the framework on a model that has begun the thermal expansion process.

1. Investic is a Gypsum Bonded investment, which has a 1500-1550 degrees Fahrenheit threshold before it begin to breakdown. Chrome cobalt burnout temperature is between 1800-2100 degrees Fahrenheit. Oxy-Phosphate and Ethyl Silicate investments are designed to withstand these temperatures, Gypsum Bonded Investment will not.

1. Investic is a Gypsum Bonded investment, which has a 1500-1550 degrees Fahrenheit threshold before it begin to breakdown. Chrome cobalt burnout temperature is between 1800-2100 degrees Fahrenheit. Oxy-Phosphate and Ethyl Silicate investments are designed to withstand these temperatures, Gypsum Bonded Investment will not.

Several reasons for stone and oxy-phosphate models to give this appearance;

1. Taking longer for the investment or stone to set-up may be directly related to the water temperature use to chill the hydrocolloid. Water bath should be about 55 degrees Fahrenheit; therefore, the colloid should be at that temperature when pouring the gypsum or oxy-phosphate material. The colder the temperature of the colloid the longer it will take gypsum and investment to set properly.

2. Chalky , soft and smudged surfaces may be due to;
a. Insufficient set time
b. Colloid temperature too cold
c. Improper liquid powder ratios
d. Insufficient mixing time of the gypsum or investment material