If you have ever driven your car in the snow or mud only to emerge with shorted out servos or receiver then you might want to read this article.

Despite what you might think about servos most are water-resistant at best. The first thing you might want to do is take apart your servo and look inside. Notice there is a rubber O-ring on the edge these rings are there to seal your servo from water. However, the main place water will enter your servo is via the actuator shaft. Sealing that shaft is often the most difficult part.

It is important to note here that before you try any of these methods you might want to first try it on an old servo you don’t care about. I offer no guarantees or promises on any of these techniques.

So here they are from worst to best order.

The Balloon Method
One of the most commonly used methods for waterproofing servos and receivers is the balloon method. For this you take a common balloon and squeeze your sever down into it. You then cut a small hole in the balloon and push the actuator head up through the hole. The key here is to make the hole smaller than the head of the actuator. Then you run the wires back out the hole and zip tie them. This method will work for snow and some light mud but it is definitely not water PROOF.

Plasti Dip Method
This method is slightly better than the balloon method, but it still leaves the actuator shaft exposed some what. You can purchase Plasti Dip from most auto parts stores or home improvement store. It comes in a couple of flavors, dip and spray. Once you coat the servo with the Plasti Dip hang it up and let it dry. The biggest issue you will have with this method is once coated the shell of the servo is now a few millimeters thicker. If your servo needs to fit in a predefined size slot this method will not work for you. Also once again your actuator shaft is exposed to possible water leaks. Again this will make your servo more water resistant but not waterproof. One idea you might try is to put a small red shock O-ring around your actuator head before you mount your servo horn. This will help to seal the shaft better. Also put a bit of old on the O-ring to help repeal water and reduce friction. NOTE: make sure your sealant oil is not the same material as the O-ring (for example, don’t use silicone oil with a silicone O-ring).

Super Glue and O-ring Method
Basically this method is the same as the Plasti Dip Method only instead of dipping the whole servo you are super gluing the sections of the servo together. Start by taking apart your servo and then super gluing each part back together (be careful not to get glue on the gears). Then re-screw it all back. Next put a blob of glue where the wires go into the servo body. Lastly add a O-ring to the actuator head as stated in the previous method. This should waterproof your servo for heavy water use.

There is an additional step you could perform before you do the super gluing. That is to fill the servos with non-conductive oil. There are a number of oils you could try such as cooking oil, mineral oil, or silicone oil.

To do this you need oil, a wide container that holds oil, gloves, super glue (something that dries in under 5 minutes), a screwdriver, and either acetone or hexane. Tweezers are also recommended, but optional.

The first step is to poor the oil into your container. You want about one to two inches of oil (or enough to completely cover your servo). You may also want your container to be inside a second container, to avoid spilling oil everywhere. Choosing a container that BOTH of your hands can operate in is very important.

Now you should disassemble your servo, and put all parts in the oil. Make sure you shake out all of the bubbles.

Ok now the really hard part, reassemble the servos while they are fully submersed in oil! Make sure you practice disassembling and reassembling the servo outside the container a few times before trying to reassemble in oil. Its 10x harder to do it in oil, so practice is good.

A few potential issues, handling the tiny screws of a micro servos while wearing gloves is a challenge. Using tweezers to pick and place the screws could save you tons of time. The oil is also optically distorting, making it hard to see what you are doing. Make sure you have good lighting. You might also have trouble operating the screwdriver, since your gloved hands are covered in slippery oil. Make sure you use a screwdriver with a good grip handle.

After you get the O-ring and servo horn on, and you make sure the servo is screwed together really well, take the servo out of the oil and clean it off. To do this, dab it with a paper towel that is lightly soaked in acetone or hexane (dissolves oils). Both give off fumes (especially hexane) so do this in a well ventilated area. Neither chemical damages the servo casing, but acetone can potentially dissolve the plastic gears and electronics, so be careful. NOTE: Acetone can also dissolve screwdriver handles.

Lastly, apply the super glue (that is designed for plastics) to all the seals.

To verify that your seal is good, let the servo sit out for a day or so. Come back and if any oil is still leaking, clean it off and apply more superglue to that area.

Cons: Superglue isn’t that permanent and acetone and hexane can dissolve the glue. Also over time the oil will start to leak out.

Super Glue and O-ring Method On Steroids
The last method is another spin on the super glue method. It is easier to watch this video than try to explain it.