Tips for cleaning your housing after a dive

I have recently started using a rocket blower/compressed air to remove water from around the push buttons and control knobs on my housing during my post dive maintenance . I was amazed the first time I did it at the amount of water that came out of them. Even though the majority of it should be fresh any residual salt will promote corrosion, as will storing it wet/damp.

I have even used it on strobe buttons/controls and works a treat.

Does anyone have other tips that are not well known?

My current post dive maintenance is

Soak in freshwater

Operate all functions (housing/strobes/focus light)

Dry with microfiber towel

Blow out all areas water can sit

Leave with a fan on it for 24 hours prior to storage in a well ventilated area

If you want to blow it out, these things are pretty nice for that purpose. They attach to a BCD hose.

https://www.piratediver.com/Marine-Sports-Air-Blower-Nozzle-Air-gun-p/1881.htm

I rise with clear water on resort, then when I get home soak all my items in a tank normally over night pressing all functions buttons.

then leave to dry, I dry port glass then clean all marks off the glass, once all dry, I maintain my housing as per manufacturers recommendations so in my case lightly old once dry, store until next time.

Andy. 

On 2/18/2019 at 11:36 AM, Vondo said:

If you want to blow it out, these things are pretty nice for that purpose. They attach to a BCD hose.

 

https://www.piratediver.com/Marine-Sports-Air-Blower-Nozzle-Air-gun-p/1881.htm

i use this if i have to change batteries between dives, works great.  I also use it to blow all the water off my 1st stage before swapping it to a new tank.

I read somewhere about soaking a housing in distilled or denatured water which might get salts out better than regular tap water.

I tried it once. I can't say I had any sort of epiphany. Nor I think did the housing. But maybe one of our more scientific colleagues can comment?

Tom K your kind of thing eh?

Warm water around 40/45 degrees celsius is supposed to help breakdown salt as well.

How about warm distilled water 

4 minutes ago, Chris Kippax said:

Warm water around 40/45 degrees celsius is supposed to help breakdown salt as well.

How about warm distilled water 

... with a slice of lemon?

Like a relaxing tropical hot tub for your housing

A soak in de-ionized water may help.

I know it leaves my car spotless!

A dip in the rinse tank while wiggling the controls, then out and in the dry. 

When I need to crack a housing open for another reason, check the o-rings and clean/grease only if necessary.

I have seen many more photographers love their housings to death than I have seen abuse their housings to death. Left unattended in a rinse tank to slowly fill with water; over-maintaining o-rings and mistakenly trapping a fibre.......

It is not rocket science, the issue is you get salt water inside easily - the housing is dry and the water is pushed in by pressure to fill the area around the button or shaft up to the o-ring.  The pressure pushes the air out easily.

When the housing comes out of the water there is no driving force to speak of to make the water leave and surface tension tends to hold it in place.  So you soak it in water and work the buttons to force salty water out to be replaced by fresh.  You get maybe 50% exchange of salt water for fresh each time.  so each press might reduce salt concentration by 50%.

While it is soaking the driving force is diffusion to speed up diffusion warm water and low chloride concentration will help.  The driving force is the concentration difference of the sodium and chloride ions between inside the button hole and the bulk water.  De-ionised water may help a bit but most tap water is so low in chloride ions it would hardly make any noticeable difference.

Other things that might help might include blowing out each button with a blower bulb so that it fills with fresh water when you immerse the housing and also blwoing them after taking out of the tank.  I soak mine for about an hour.

I also soak my Z-240 strobes for the same time, you can't work the battery cap and there is water between the cap opening and the o-ring.  I have soaked them for an hour and left them on the bench at home for a day or two to dry and when disassembled the water has evaporated and there are salt crystals there - it won't harm that o-ring as you are not forcing the cap on and pushing the o-ring into the salt, but it goes to show that all the buttons on your housing need assistance with flushing if you don't want salt crystals forming there. 

The geometry of the buttons is perfect for crevice type corrosion and eventually you might get pitting on any stainless steel shafts reducing their ability to seal.  and the crystals will eventually damage your o-ring.

A long soak when you get home if you are not going to use the housing for a few days can't hurt and it probably can extend the life of your housing.

Has anyone considered using the vacuum valve with a pump instead of a vacuum to keep the housing under slight positive pressure after it’s been removed from the rinse tank to push water out from the o-rings? My fear is you risk dislodging an o-ring.

Bad idea IMHO. I would consider pressurising my housing and using soapy water to find a bad o-ring but not routinely for cleaning. I do a bit of pressure testing at work and a couple of PSI would be sufficient (2/3 psi)  and too much pressure could damage it catastrophically. The housing is not designed to withstand internal pressure only external. 

I think if you follow the above tips your housing should enjoy a long trouble free life.

It probably would not work to remove water in any case, O-rings should seal in both directions if they are contained properly. normally the o-ring sits in a groove and that type should seal in both directions.  But other components like the viewfinder or rear window may not be designed this way and could fail.   So risk of damage and also ineffective.