Waterproofing Stepper Motor -- Mineral Oil?

Thread Starter


Joined Feb 21, 2010
Hey everyone,

I have been looking into ways to waterproof a stepper motor and I came across a video on how to waterproof a servo using RTV and mineral oil. The inner working of a servo and a stepper motor are different, and I am wondering if this technique could be used on a stepper with no harm.

The project I am working on is a nozzle positioning system for a water fountain, and it includes three stepper motors in the design. Since they will be constantly exposed to water, I need a reliable way to waterproof them so that they will not lose functionality.

Here is a link to the video I am referring to.


Any suggestions?




Joined Feb 5, 2010
You should use a motive power suitable to that environment.

Fluid, or even air motors, not electrical.


Joined Jul 7, 2009
You'd want to be careful about changing the thermal characteristics -- I've seen applications where stepper motors get quite warm to the touch; you'll set yourself up for early failure if you run the motors too hot.

If the motors can be enclosed in a waterproof box (again, worry about the cooling), it wouldn't be too hard to make a shaft feedthrough that would be watertight (but it depends on the shaft's speed). See your local bearing supplier for recommendations. If it was me and the shaft speed was slow, I'd just use a couple of well-greased o-rings and make my own seal. I'm assuming you want splash-proof type seals, not immersion.