Looking after wet electronics^

[Jon Wood]

I have just purchased a hand-held Icom VHF.
It is JIS grade 7 (1m/30 min) watreproof rated.
The manual simply recommends washing in fresh water and making sure the antenna is securely fixed
From past threads I see that storing it in an Aquapac may cause as many problems as it prevents.

Is there any merit in using silicone grease on the contacts to prevent corrosion, or any other precaution that should be taken beyond giving a good rinse at the end of the day? The same advice also required for the new WP type cameras etc.

(I have attached a decent lanyard)

[gizmo]

Hi Jon - I bought an Icom Vhf about a month ago and as recommended I've washed it in clean water after use and everything seems fine. I wonder whether doing anything else might not void the warranty??

[Canuck]

Silicone on the battery contacts sounds like a great idea. I try and keep a pencil w/eraser handy for polishing the corrosion off, and a little grease will likely go a long way as an ounce of prevention.

Thanks for the tip.

[John W]

Both my GPS and VHF spend their lives afloat in Aquapacs and are both still like new after many years use. The Aquapac also helps them float much better and stops them getting scratched; however it does make the VHF a little bulky for BA pockets. Condensation on a sunny day can make the GPS a little difficult to read sometimes but it is not a big problem.

I have seen a number of VHF rotary channel/volume controls corrode to point of unserviceability over time, where they have been used without any protection.

I know there is a school of thought that trapped water vapour in the Aquapac could work its way past the seals but I'm not convinced by this. I can't see that vapour at atmospheric pressure can get past a seal that is designed for 30min at 1 metre, but I may be wrong...

JW

[ChrisS]

I keep a small sachet of silca gel sachet in my aquapac to remove water vapour. It needs to be dried out occasionally, something I haven't yet bothered to do. When I do get round to it I'll just give it couple of minutes in the microwave.

[Pelagic]

I know there is a school of thought that trapped water vapour in the Aquapac could work its way past the seals but I'm not convinced by this. I can't see that vapour at atmospheric pressure can get past a seal that is designed for 30min at 1 metre, but I may be wrong...

Neither am I John, and a little sachet of silica gel inside the Aqapac solves the fogging problem.
It cost quite a lot in dead electronics before we stopped believing manufacturers claims to be waterproof. I have used Aquapacs for years now with no problems with dead or corroded electronics, of course eventually the Aquapac fails, normally round the lanyard eyelets or the clamp seam. cheaper to replace than a VHF or GPS anyway.
As a final thought, silicone grease should also be smeared thinly over any "o" ring or gasket seals as well as the contacts themselves, make sure its the fine stuff and dont do it on the beach! A very thin film is sufficient.

Phil

[John W]

Phil

I have had 2 Aquapacs fail now, just wear and tear really. But both times I have contacted their customer services and had replacements provided without any hassle. How customer service should be.

[Dave Thomas]

what is a good source of suitable silicone grease?

Dave Thomas

[Robert Craig]

Maplin.
Though can't find my catalogue to check.

[Steve B]

http://www.maplin.co.uk/Search.aspx?cri ... &source=15

or RS Components - http://rswww.com - and search for silicone grease (poorly designed web site doesn't provide a direct link).

[Canuck]

Dow Corning makes an excellent product they call R4 electric insulating compound for use on automotive wiring. Check your auto/marine electric stockist's for silicone dilectric

Dow also makes a silicone grease valve sealant #111 which would likely be ideal for the gasket/o ring application mentioned by Pelagic.

I've had two Garmin e-trex failures in as many years. I'm guessing the water made it's way past the gasket on account of the pressure differential when the gps slid off the hot black spray deck into the cold water. The latest replacement has a small hole in the back of the body. I'm presuming there is some kind of bladder behind it to offset any sudden change in pressure.

[Dave Thomas]

Thanks for those suggested sources!

Dave Thomas

[Chris Bolton]

Looking at those links, silicone grease is described as an insulator. Putting it on contacts would stop them corroding, but wouldn't it introduce a resistance?

Maybe a thin film is OK as the resistance will be small? Any electrical experts who can clarify the position?

Chris

[Pelagic]

Putting it on contacts would stop them corroding, but wouldn't it introduce a resistance?

Im no expert Chris, however.The actual contact surfaces should be clean and bright. It obviously depends on the individual design of gizmo. I personally dont grease battery contacts in GPS or VHFs apart from one radio which uses rechargable AAs. I do however liberally grease the brass contacts in my Petzl Duo then carefully clean the actual (raised) contact area it stops that green verdigris look. Geoff and I are both pretty liberal with the stuff on so-called waterproof switches as well (we use electric pumps) It certainly seems to help with that "atmospheric corrosion" that most things in a sea-environment are prone to.

The crucial thing is that gaskets and "o" rings need to be greased, it is normal to get a small sachet with cameras, headtorches, waterproof housings etc, but strangely not with GPS or radios. However the principle is well documented.

Damn useful stuff silicone grease!
Try a thin film around the rim of a weepy hatch. Dead good. Also flare tubes and the threads on gas canisters............possibilities are endless.
Nearly as useful as self-amalgamating rubber tape!

Phil

[MikeB]

Should it also be used on the seals on a camera? (33WR for instance??)

Mike.

[David P]

I don't see any reason why not ... The golden rule has always been the merest film of grease - typically applied between fingertips (hence you can feel any imperfections, grit, hairs etc on an o-ring).

The only problem is knowing which type of grease to use! See eg the "Cameras Underwater" website. In practice, the only product I've used that needs "funny grease" are the Olympus camera housings - all the other housings/o-rings etc I've come across are black rubber ones where silicone grease should be just fine.

Good luck!

[Pelagic]

Hi Mike,
cant add anything to Daves reply, except to say the Pentax is water resistant, this is manufacturers double-speak for "not waterproof" so no guaruntees!

I remember a friend of mine telling me that greased "o" ring seals, as well as helping to prevent "vapour transmission", whatever that is, also help to prevent the rubber seal puckering as its being closed. Makes sense really, its more slippy. I remember he explained it as being "relaxed in its seating" such a nice turn of phrase! The main cause of leaks apparently after sand and grit etc.

Phil

[Steve B]

Looking at those links, silicone grease is described as an insulator. Putting it on contacts would stop them corroding, but wouldn't it introduce a resistance?

No, the amount of grease which actually remains between two contacts when they are closed is too tiny to be of consequence. A thin film of corrosion, on the other hand, forms an insulating layer which is bonded to the metal.

[Robert Craig]

The wee breathing hole on the back of a eTrex doesn't have a bladder behind it. There's a small disc of Goretex, which keeps the water out but lets air in and out. Clever!

[Chris Bolton]

Thanks to those who clarified the purpose of the grease for me; I shall make a point of getting some. My fairly ancient Garmin GPS leaked through the battery compartment while in a (non-waterproof) deck bag in Greece. I suspect thermal effects, but grease would probably have helped. (I stole its Aquapac for my mobile phone....)

Chris

[andreadawn]

Should it also be used on the seals on a camera? (33WR for instance??)

Nikon used to supply a tube of silicone lubricant for the seals on the Nikonos and my new Canon underwater housing was also supplied with some for the seals.

Andrea.

[David P]

Hence, Andrea, my point about the right grease fot the job. Yes, I've got the Nikon grease too (came with my Nik III) - but be careful about assuming you can use the Canon grease on the Nikonos or vice versa... They may be using quite different o-ring materials. But I'm sure you know that :-)