I was flying at this beautiful seaside spot a few days ago, but my quadcopter failsafe’d and fell into the water. This is a good case study and we can talk about what to do after getting the drone out of water.
I think I was flying too low and lost line of sight with the quad (blocked signal). Luckily I had DVR recording, and I found out where I crashed. I didn’t crash too far into the ocean, so when the tide was getting lower, I found the quad!
The quad in the video – Flipmode.
Is the quad still working?
If you crashed in a river or lake (not salt water), it’s more likely to save the quad when retrieved fast enough. But salt water is much worse due to the corrosive nature, it’s extremely bad for electronics and can almost instantly destroy your quad (especially when powered on).
Unfortunately, my quad is nearly totally dead, except the FPV camera (Eagle 2, probably because of the fully enclosed camera case, and the water couldn’t get in). I also managed to salvage the motors, frame, buzzer, FPV antenna and props. But I probably have to change out the bearings on the motors as they feel a bit rusty now.
I’ve seen quads survived after bathing in water, but it’s not uncommon that some components can be damaged so don’t get your hope up if this happens to you. Even if you managed to save the parts, you should test them rigorously before flying them again. Especially the RX and VTX, do range testing on them carefully.
It’s really a hit and miss. Maybe it’s not worth the effort saving those components after all because the corrosion doesn’t stop once it starts. After you think you have “fixed” it and the components that seem to be fine today, performance may degrade quickly, or even fail in a few days.
All the steel hardware (bolts, nuts) have gone rusty, but titanium and aluminium don’t seem to be affected.
What to do after mini quad submerged in water
Take it out of water and disconnect the battery ASAP!
Wash with Alcohol
Take everything apart, remove all the heatshrinks.
Wash electronics with high % rubbing alcohol (e.g. 99+% isopropyl alcohol) and a toothbrush to clean the residue/minerals and corrosion. Best to do this before it dries.
Rinse in Distilled Water
Put the parts in a bucket of fresh water (distilled if possible). It’s better to remove the lens from the camera to avoid getting water trapped in there that can cause fogging later on.
Let it Dry
To dry it, it’s best to rinse it with 99% alcohol, most of the water will evaporate within minutes. But if you don’t have alcohol, you’d want to leave it for a couple of days to dry, the longer the better. Some people prefer to put it in rice to speed up the process, but I think an hair dryer might be a better alternative. Also oil the motor bearings, or even replace them if they necessary.
Before powering on for the first time, check for short circuit with your multimeter. Use a “Smoke Stopper” if possible.