Waterproofing a servo

OK guys - I confess I’m an electronics ignoramus. [:-dunce]

I’m considering adding further waterproofing to a Hitec HS-5745MG. In particular, coating the servo casing with a liquid rubber compound. BUT - the servo has some copper (?) strips around the outside of the casing which I’m guessing have something to do with heat - or rather heat dispersal. Right or wrong? Is coating the casing a good idea/bad idea?

Thanks guys.


You are probably right that those are for heat transfer. You may want to call HiTec to make sure (or you could send them an email).

If you cover them with a rubber compound, you have destroyed any chance of heat rejection.

Have you tested the case for water-tightness? I have found most servo cases are very aterproof except around the output shaft. Some manufactures sell seals that you can insert into the output shaft hole to make them a little more watertight, but I have found that by installing the servo with that on top so that that area would be the last to go “under water” makes them pretty waterproof.

The bigger thing to worry about is your reciever and all your connectors. The recievers are generally not very waterproof as they have holes for things like crystals and connector plugs. If any piece of your electronics kit is going to suffer from the effects of water it will either be your reciever or your battery. I have found that as long as you protect these two items, you are pretty safe. That is also why you see many IOMs with a waterproof pot for the reciever and batteries, but the servos are not protected.

Is there a specific application where you need something more waterproof than usual?

  • Will

Will Gorgen

Thanks Will. No - just nervous for my new servo. They are, as you know, a whole lot more expensive than both the receiver and the battery pack, which are in any event, as you’ve noted, pretty safely tucked away in a waterproof pot, with the cable exits as high and as well sealed as possible. This model of servo claims to have some waterproofing as standard anyway, but I think I read some where thay Ken Binks does some additional waterproofing on the versions he customises for sale via K Bits. I may be wrong there. I’ve since checked an confirmed that the copper is an external heatsink - so clearly it should be allowed to do it’s job.

I shall place faith in my deck patches!


for waterproofing the receiver:


_/ if it isn’t broken, don’t fix it! _


While we’re on the subject - and this is a warning - I’m poverty-stricken and am always looking for ways to save a buck: I’ve bought several of Tower’s Hydrimax receiver pack over the years. Being the proud owner of several leaky boats, the packs are always swimming in bilge water. Every one of the packs has gone bad after a year or two - sometimes in less time. I finally dissected one - and there was so much corrosion/rust that the solder joints were letting go. The pack’s wrapping isn’t tight enough. For what it’s worth, I’m going to try repairing and resealing them.

On the other hand, I also own several of those cheap green packs sold on Ebay - and not one has given up. So…

There is nothing - absolutely nothing - half so much worth doing as simply messing about in boats. Kenneth Graeme, Wind in the Willows.

Most of our on board electronics can be protected from getting wet by putting the items into a Balloon !.
Go to the Kiddies shop and buy a pack of Party balloons.

Cut the neck off the balloon just where the body of the balloon gets bigger, leave a bit of the neck on.
Stuff the receiver into the balloon with ALL the wires coming out of the neck, dont pull the balloon too tightly around the receiver and gather all the rest of the balloon round the wires.
All the wires should be laid out as neat as possible, in a round bunch.

Get some Putty, or Modelling clay and make a collar into and around all the wires.
When as many of the wires are coated with the “sealant!”, tape the collar with some stretchy Tape, or a tight rubber band.
Same trick works for battery packs, be carefull when fast charging Nicads, they can give off gasses which can cause the balloon to inflate a bit!!.
Cut off the bits of the balloon which is sticking out past the seal, job done!.
I have also had leaky boats and this works!.
JayDee. [:)]

[:D][:D][:D] I was going to suggest a “different” kind of ballon - but with the same results ! [:-censored][:-eyebrows]

A Surgically Protected Receiver?.
You really are getting better!.
JayDee. [:-angel]

Ha! Balloon guys…all the same


_/ if it isn’t broken, don’t fix it! _



I think I’ll commercialize your idea. I’m going to call it the “Futaba Rubba”, or maybe the “Hi-prophylac-tec”. Do you want royalties?




_/ if it isn’t broken, don’t fix it! _


with sensitol?

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Oops guys. I think we’ve offended Dick. Perhaps we’d better take our discussion on “Safe Servos” to The Local Pub instead.[}}:-|>>]


Not me - I’m so “off color” somtimes I even offend myself. [:-eyebrows]

One easy way to prevent moisture damage to a Rx is coat the servo connections with di-electric grease.

Precision Park West:
Higher Technology Racing Solutions
“Beyond Hyperbole”

when all else fails a bit of fresh water and some NO2 cleaner does wonders for dipped electrics

Live Hard, Die Young and Leave a Good Looking Corpse