Filling Thrusters with oil

[Sky]

Hello All

I have found some nice seals which I would like to use for my thrusters. But they are only rated down to 8m. If I fill the thruster with oil the depth rating should
increase right? For the pressure compensation using oil is it enough if the thruster is just filled completely with oil or will I need a reservoir with some sort of diaphragm
that will decrease the volume inside the thruster proportionally to the water pressure as well? And what oil is best used for this type of application?

Any help Appreciated
Philipp

[Never prototype]

You can have issues with brushed motors in oil because pieces of brush end up in the oil and increase its conductivity. Equalizing the pressure is easily accomplished by using a rubber plug on the housing somewhere. You can use corn oil but it apparently gets sticky when exposed to air. Use it if your motor is brushed and you need to change it frequently because its cheaper. Mineral oil is otherwise a better choice because it wont gum up.