Underwater robotics and aquatics can be very fun. Technically small motors will work okay in submerged in water. But let's be honest. Nobody likes maintenance after every use. This instruct able will be a guideline to constructing a water resistant case to better protect the motor and cut down in maintenance. And can be made with relatively few bought materials if you already own the majority of these tools.
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Step 1: Supplies
The following supplies are not hard to find and can be purchased at most auto parts stores and department stores. Supplies: Ã¢ÂÂ¢bottle (old film can or prescription container) Ã¢ÂÂ¢marine grease Ã¢ÂÂ¢marine silicon Ã¢ÂÂ¢dremel (with assorted bits and tools if required Ã¢ÂÂ¢hot glue gun Ã¢ÂÂ¢old motor gear.
Step 2: Drill the Shaft Hole and Hole for Wiring.
Find a suitable container that is the same size or around to the motor. Use a drill bit that is the slightly bigger than the shaft and a hole for the wires.
Step 3: Pack the Bottom of the Housing With Grease
Use the marine grease to pack a layer of at least 3 mm where the motor shaft will protrude. Wipe off any unnecessary grease from the internal housing and from the shaft once its out.
Step 4: Hold Motor in Place
Use a spare gear to hold the motor in place. After i made the hole for the shaft and proping the motor, i used this leftover gear salvaged from a cd player to hold the motor upright so i can apply some light hot glue to brace the motor. If using this type of gear and engine is still crooked, try to use some note card shims between the housing and gear, it work wonders in my case. Use a hot glue gun to drop some glue into the container as a makeshift support. Make sure that the motor is upright and stays upright till the glue dries or the shaft will be crooked. Most people would suggest to pack the whole container with grease but I don't to save on weight. It's your call. After the glues dries, it's time for the second step.
Step 5: Seal Everything Up
I used marine silicone to seal the other openings from water. Such as the wire opening and the threads of the cap or lid of whichever you used. I like to seal by applying sealant to the inside of the lip and then applying a light outer coat. Some used hot glue, however this has been known to leak in my case. Whatever works for you or what you have available.
Step 6: Your Done
Once your glue/silicon dries and/or cures your free to use your new water resistant housing.
Step 7: Notes From the Author.
It's called a water resistant housing for a reason. Since the hole still exists in the shaft. It's only protected from water by a grease layer. Which means you can only go so deep before water pressure will defeat you. This is also a trial and error project. What I want for everyone to pick up from this is that you can use this for any container of your choice. It doesn't need to be what I used. I used these because they happened to be lying around the house. My first design tried to use two motors in a housing but that failed so I opted for individual housings. I encourage everyone to improve upon this and spread it around so that everyone can build their own. Anyone can buy a waterproof motor but there's always a self satisfaction when you can build one yourself.