When we moved east from dry northern Arizona to the very humid state of Florida, controlling corrosion on our trusty Cardinal became a full-time job.
Like many other birds, we keep them in a hangar and treat the plane's wings, fuselage, and tail feathers every few years with an internal spray corrosion treatment program. I fly him at least once a week and each time I bring the engine up to operating temperature and keep it at that temperature for at least 45 minutes.
But we wondered how we could protect our precious radio stacks from the ravages of moisture and salt.
I used to have problems with humidity and other electronics. Over the years, I've found that if you leave your musical instrument amplifier in a humid environment, the rheostat contacts corrode, causing a loud crackling noise when you turn the volume up or down. Thankfully, spraying a little contact cleaner onto the piece and turning the volume knob vigorously usually resolved the situation. Come to think of it, I had the same experience with the volume and squelch controls on my Cessna's intercom.
Our instrument panels showcase a piece of avionics history, from a 30-year-old intercom system and three light marker beacons, to some of the venerable King KX 155 NavComs, and more recently, digital transponders, IFR GPS, and autopilots. Contains the entire range. I've noticed that every time I open a box with these new digital toys, the first thing that falls out is a small pack of silica gel, commonly referred to as desiccant. When these precious little devices are shipped, manufacturers take the time to protect them from excess moisture. At this point, my trusted co-owner, co-pilot, and spouse found themselves making this kind of moisture-absorbing desiccant for closets, footlockers, and even entire rooms. . A trip to the hardware store was in order!
Full disclosure, the content below is not backed by scientific research, but rather the product of backyard engineering skills and a little experience.
The item I purchased most was a “closet hanging moisture absorbent'' that is designed to hang next to clothes in a closet to catch absorbed moisture. The top of the bag is filled with absorbent material and the bottom is a clear plastic bag that catches water. These come in a variety of sizes and are manufactured by several companies.
As it turned out, the plastic hook on the top of the dehumidifier fit perfectly into the polished Cessna's control yoke shaft. These come in packages of 3 to 8 pieces and typically last several weeks in humid weather.
Purchase number two was a bright red plastic bucket. After reading the instructions on the dehumidifier box, I learned that the water bag does not leak and no other precautions are necessary. I've always thought Murphy's Law was incredibly optimistic, so a $5 bucket seemed like a good buy. The rest was easy. Hang your bag over the passenger side control yoke shaft, place the bucket on the floor directly underneath the bag, close the door and wait for the magic to happen.
Well, not so fast.
Unless you want to dehumidify all of Northeast Florida, it makes sense to check that door seals fit properly, close outside air vents, and make sure the cabin is relatively sealed from the elements. It's good.
The results were unscientific. The corrosion problem with the intercom system has not recurred. The bags and buckets are easily removed and replaced before and after each flight, and the bags fill up on time and as promised. Oh, and the inside of the Cardinal is drier and smells even better.
This unscientific dehumidifier costs about $5 per bag plus a bucket. Peace of mind: Priceless!