Apologies if this isn't on topic; let me know and I'll remove it.
Having keyless fobs is quite wonderful, but it does seem easier to accidentally put the key through the laundry cycle because it never comes out of my pocket and I thus forget it's there
Having fully washed and dried the current car's fob for this, third, time (the previous two times I've had a moment's realization and stopped the cycle before too much water got into the fob) I cracked it open to find a few of the solder joints looking a bit furry and corroded, battery was ruined (never seen rust around the edge of the -ve of a CR2032 before), but scrubbing with distilled water, rinsing and blowing off with the air compressor and replacing the battery seems to have produced a working fob.
I'm not sure how many time I'm likely to be able to repeat the stunt so I'm looking for a way to protect the board from the laundry. The rubber seal on the housing itself is intact, but seems poorly designed (ford fob) compared to my previous (volvo) fob that went through the wash many times and was always bone dry inside
I'm hence looking to find out of the board itself can be coated with something protective. I'm not too bothered if this coating cannot protect the mechanical switches as they can be replaced if they get ruined - I'm more thinking the antenna coil, ICs etc. I'd also have to scratch it off for the battery terminals, so i guess I'm looking for something that adheres to the board, and cannot be cleaned off by up to 60 degree water but I also need the coating to be thin because there isn't a lot of space inside the fob. I read some sugggestions here but epoxy/urethane don't seem thin enough, "acrylic conformal coating" is a bit vague and I've a doubt marine grease would survive the wash temperatures without causing issues for clothing
I'm not averse to dipping the entire fob external housing in plastidip, but the result would be a bit ugly; I'm keen to know if a PCB based solve would be more workable