Waterproof A Receiver

By Paul Williams.
Article posted 19th March 2008.

This article is a quick guide to waterproofing a receiver for a fast electric model powerboat. Getting the radio system wet is a prime cause of breakdowns, glitches and, in some cases, crashes. It is usually impossible to build a boat that is 100% watertight. Accepting that water will always be present to some degree, and acting accordingly to minimise the problems it can cause, will dramatically increase the reliability of your boats.

Take a look at this article if you want to waterproof a servo. Waterproofing a receiver is done a bit differently. A servo has its own ready made case that is easily sealed against water ingress. A receiver, however, has a case with a number of openings for servo and speed controller signal plugs, crystal and aerial wire, so waterproofing is much harder.

The traditional method of waterproofing a receiver was to place it inside a balloon and seal the neck with a tie-wrap. People still do this, but personally I don't think much to it. In my experience, the balloon method merely collects water and keeps the receiver soaked - hardly what you want. The balloon method is quite an ineffective way of keeping a receiver dry, to say nothing of the problems of having to unwrap the receiver whenever you want to check a connection or change the crystal.

The best and simplest method is to treat the internals of the receiver with an electronics-grade product like conformal coating or, as shown here, an electronics-grade silicone grease. This way, even if the receiver gets soaked, water is kept from the electronics by the applied coating. In this article, I'm using a PTFE-loaded silicone grease from Maplins. An alternative product is "conformal coating", an aerosol applied coating that conforms (hence the name) to whatever it's sprayed onto. Conformal coating needs to be allowed to cure thoroughly, and you will need to apply 2-3 coats to get a good water barrier.

Receiver for waterproofing.

Carefully take the receiver apart, splitting the case with a small flat-bladed screwdriver inserted into the snap-lugs.

You do not want silicone grease on the signal pins. To save having to wipe it off afterward, push a small scrap of pink or blue foam over the pins prior to treatment.

It's best to treat a receiver when it's brand new before water has had a chance to get into the electronics and cause corrosion. Take the receiver and split the case apart using a small flat-bladed screwdriver to open the snap-lugs that secure the two halves of the case together. Remove the circuit board from the case, and push a small scrap of pink or blue foam over the signal plug pins to keep them free of grease. Note that conformal coating will melt pink or blue foam, so you can use a small block of soft balsa instead if using conformal coating.

Spray on a couple of coats of grease, or 2-4 coats of conformal coating. Allow conformal coating to air-dry before replacing the receiver case. Silicone grease won't dry, so you can put the receiver back in its case straightaway.

© Copyright Paul Williams and www.fastelectrics.net, 2010.

This article may not be reproduced wholly or in part without the written permission of the author and www.fastelectrics.net. If you would like to use this article or the accompanying pictures/diagrams please email articles@fastelectrics.net.

Last modified: 08th July 2010 @ 09:06