Crazy Condensation?

[kbowen]

In an effort to protect some electrical connections and solenoids I went over-the-top by putting them in what i thought were watertight boxes. I put my 12V anchor winch solenoid in a clear industrial plastic box that has gaskets and cable inlets with rubber glands. I also have a solenoid bank that switches my two batteries from 12V parallel to 24V series for the auxiliary (trolling motor) which I housed in a steel military ammunition box, again with cable inlets which have rubber compression glands. In both cases I have had water mysteriously accumulate in the enclosures and corrode the connections. does anyone have a clue WTF?? Photos attached.

Ken

IMG_7193.jpgIMG_7194.jpgIMG_7197.jpg

[lupussonic]

Re: Crazy Condensation?

Anything that cycles warm-cold-warm-cold will pull outside air into it on its cooling cycle. As expanded warm air cools it shrinks in volume and sucks in cold air, which has water vapour in it. Your ammo box might keep rain out but it is not a great seal against even a gentle vacuum.

The clear plastic box evidently does not have good mechanical seals.

[wizbang 13]

Re: Crazy Condensation?

My solenoid winch thingy just hangs on the wires a few inches below the windlass , in the focsle , of my ocean bashing boat.
i spray it with sweet water then "corrosion X" after the anchor goes down .( along with numerous other things)
no ammo box...no gland skin fittins, no corrosion.

[kbowen]

Re: Crazy Condensation?

Anything that cycles warm-cold-warm-cold will pull outside air into it on its cooling cycle. As expanded warm air cools it shrinks in volume and sucks in cold air, which has water vapour in it. Your ammo box might keep rain out but it is not a great seal against even a gentle vacuum.

The clear plastic box evidently does not have good mechanical seals.

Ok, so what happens with live ammunition? Do those ammo boxes fill up with moisture like my solenoids? And btw, what causes clear containers to get droplets on the inside when in the sun? It's totally counter-intuitive to me.

Ken

[lupussonic]

Re: Crazy Condensation?

Ammo doesn't get warm.

Your clear container is not air proof.

[Rumars]

Re: Crazy Condensation?

The air you trapped into those containers contained water, wich condenses and evaporates regularly with temperature swings. Even if your containers are air tight (wich you can observe by watching for pressure related deformations) if you don't remove the water from the air this will happen. Electronics that have to be sealed air tight are vacuum evacuated and purged with dry inert gas.
What you can do is add a bunch of dessicant to your cans and maintain an inspection regime to keep the dessicant fresh (it can be regenerated). Alternatively install everything in a dry and well ventilated space, and use corrosion inhibitor.

[Breakaway]

Re: Crazy Condensation?

I seal all electrical connections with liquid tape or shrink tube, or use pre-made heat-shrink terminals. I annually apply Silicon spray to the terminal blocks or other exposed bits. No covers or enclosures. The boat lives in saltwater 7 months per year. A little green appears once in a while, but failures are rare. ( I do regularly inspect stuff)

Kevin