That does look like a good little tool for making small castings. HOWEVER, keep in mind you should NOT vibrate concrete for that long. It causes the aggregates to segregate, rather than remain a homogeneous mix.


For reference
"For most of concrete mixes, over-vibration creates the problem of segregation in which the denser aggregates settle to the bottom while the lighter cement paste tends to move upwards. If the concrete structure is cast by successive lifts of concrete pour, the upper weaker layer (or laitance) caused by segregation forms the potential plane of weakness leading to possible failure of the concrete structure during operation. If concrete is placed in a single lift for road works, the resistance to abrasion is poor for the laitance surface of the carriageway. This becomes a critical problem to concrete carriageway where its surface is constantly subject to tearing and traction forces exerted by vehicular traffic."