There are currently 5 gauge manufacturers; CPN (recently purchased by InstroTek), Humboldt, InstroTek, Seaman and Troxler, which collectively have more than 20 different gauge models that measure soil, asphalt and concrete density and soil and rooftop moisture. Mechanically, all soils and asphalt moisture density gauges work the same. The gauges have a source rod that lowers into the ground to measure wet density and another stationary source contained in the base of the gauge that measures moisture.
Hands-on training provided by the RSO or senior gauge operator is a very important requirement for new gauge workers. There is no practical way to cover the different software functions of all the different models in a training class or internet setting. If a gauge is in use in a live class, and even if you had time to do so, it represents only one of the 20+ gauges on the market. It would take most of the day to give each attendee the opportunity to get hands-on with the gauge. Even then, most attendees would be viewing a gauge that is not in use at their company. For that reason, along with time constraints and expensive reciprocity fees, most live class instructors have abandoned the use of gauges in the class setting.
Powerpoint presentations showing cutaway views of a generic gauge are a far more safe and effective way of showing the safety features and “anatomy” of a gauge. Back at the company, the RSO should ensure that the worker is given hands-on field familiarity of the gauges in use by the company. Other effective teaching tools are the gauge application materials available at most manufacturer websites.