The following tests are carried out and all products must pass before moving on to the next stage of manufacture. Any batch that fails a test is rejected.

• Pyrometric keys are placed on each car before it goes into the kiln. After firing, the key measurements are recorded as an indicator of fired quality.

• Six samples each will be taken from the top, middle and bottom of the car and placed in a sample bag with the kiln car card that includes the lot number. The samples are taken to the lab and subjected to the pass/fail testing described below:

• These are weighed and then placed in water filled desicator where a vacuum is pulled for 45 minutes. This fills all interior interconnected pores with water.
• The samples are taken from the water and tested for % absorption. If all balls’ absorption is below 6%, the car passes. If two balls’ absorption is over 6%, the car fails. If that of one sample is over 6% (or over 0.4%), another sample is tested. If its absorption is over 6%(or 0.4%), the car fails. If under 6%(or 0.4%), the car passes.