30 November 2018 at 12:26 #1749
Seeing as how a couple in the group have once again had premature failing of electronics due to immersion in salt water I thought it appropriate to start this thread.
I am not saying this is the be all & end all to electronics waterproofing but it is what I have used ever since a couple of early failures when I first got back into the RC boating hobby.
Start with the materials I use
1) Protective Circuit Board Lacquer from Jaycar & most good electronics shops
2) Liquid Electrical Tape from Jaycar & most good electronics shops
3) RTV 732 adhesive/sealant by Dow Corning from most auto accessory shops
4) Vaseline White Petroleum Jelly from your home medicine cabinet and almost anywhere else eg chemist, supermarket, corner store (you get the picture)
Remove the circuit board from the plastic casing,
If its a used receiver make sure you inspect it for any existing damage or corrosion & clean appropriately with methylated spirits or similar using a soft bristle toothbrush.
If brand new it should be OK but a quick inspection is still warranted.
Once clean & dry spray the circuit board (all of it including the connection pins & led) with two liberal coats of PCB lacquer allowing at least 15 minutes between coats then hang up to dry completely (preferably overnight).
Once the lacquer is completely dry apply a couple of coats of Liquid Electrical Tape & work it in well around all components & connectors etc.
Once completely dry (best left overnight), thoroughly clean the connector pins of liquid tape & PCB lacquer (only the ones you intend to use) then reassemble casing around circuit board.
Fill the connection plug hole with Vaseline before inserting Servo & ESC connectors
Than finishes your receiver now onto the Servos
Servos generally leak around the lead in cable or the case joints so both these need to be sealed.
The circuit board can be removed & lacquered but this is a rather involved process for the untrained person .
We will opt for the easy solution.
Clean the outside casing of the servo and apply a couple of coats of liquid electrical tape to both the bottom & top joints of the casing. Pay particular attention to getting a good coating around the lead in cable & the case cover screws.
Generally water will not leak through the shaft entry into the servo due to the grease in the gearbox directly below the shaft but this can be improved a bit more by putting Vaseline liberally around the servo shaft before inserting the servo horn.
3) ESC’s (Electronic Speed Controls)
The majority of better quality marine ESC’s (especially the watercooled ones) are already sealed to some degree but most will still leak if under water for any length of time.
If the casing is metal & fully enclosed then inspect for & seal any obvious joints, screws, cable entries etc. For this you can either use Liquid Electrical Tape or RTV 732 Silicone adhesive/sealant.
If the casing is heatshrink then you need to seal both ends of the shrink tube with RTV 732 Silicone adhesive/sealant.
Pretty much any silicone type sealant can be used but I find the RTV732 (used for making car engine gaskets etc) bonds better than most. It can also withstand a much wider temperature range (-60c to +350c) without deterioration.
As for temporary waterproofing of test/logging equipment such as our GPS data logger I simply use Glad snaplock sandwich bags.
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