If a local standard is to be constructed for density checking, we
suggest any of the materials we use at the factory. We not
recommend the use of any standards not fully checked at our
factory for recalibration purposes.
Moisture calibration need not be checked as the detectors are
very stable. Small changes can be corrected in the field when
field samples are taken to develop a moisture correction factor.
If recalibration is necessary and Troxler standards are not
available, contract your Troxler service center with calibration
capability.