Quote Originally Posted by A_Camera View Post
I guess your intended 2.2kW spindle will be more like: 5kg spindle + 1.5 kg motor holder + about 1 kg water + cabling... with an air cooled 1.5kW you should save about 3 kg (less weight for the motor and no water).
I could get into this deeper and tell you why you are wrong but I won't other than to say the water in the spindle is minimal, less than a cup full, so water weight isn't an issue.
The cooling comes from continuous recirculation of the water and provided the water container is large enough the spindle doesn't need a large volume of water around it.

Also, the 1.5Kw WC spindles are around 3Kg, not 5kg which is roughly the same weight as the Air-cooled. Cabling doesn't come into it because the Air-cooled still needs cable.