Surefire A2 and moisture

Question: using an A2 for about half an hour with both leds alone and sometimes with incan in the car, doors open and about 12/13ºC outside, there was a slight moisture in the inside of the lens. Is this normal ?
(i know the lens get hot, it says so).

I guess if the humidity was too high, it could happen.

Welcome to CPF

Yes, this indicates that there is moisture inside the flashlight (perhaps from when the bezel or TailCap was taken off and exposed to the atmosphere).

You chould try putting the open A2 in the airing cupboard (understand I mean subjecting it to a warm dry atmosphere for may be over a week - do not rapidly heat it)

Welcome to CPF, JorgeM. AC and Al are correct. I just returned yesterday from 9 days in the wet and have been drying gear and combating mildew.

54-55 degrees F. is plenty cool enough for moisture in the air to condense on things, particularly metal and glass. I've found a good place for dehumidifying equipment is my hot water heater closet. The temperature in my closet is a dry ~80 F./26-27 C. A day does the trick for me.

Like Al said, open up your light. Place it so that the openings face upwards. I place tubes, like flashlights in a cup to hold them upright. The moisture will evaporate and the vapor will be able to escape out of the light.

Closeup the light while it's still in the "drying cupboard", otherwise you may trap moist room air in it and start your little flashlight climate all over again. /ubbthreads/images/graemlins/grin.gif

A safe rule of thumb is don't apply temperature greater than your body temperature to any equipment you are drying, even though the light will heat up quite a bit hotter than your body temp. if you run it long enough.

Britt

"hot water heater closet"

In the UK the "airing cupboard" is usually the cupboard in which resides the hot water tank and perhaps the hot water boiler). There is likely a collection of home made shelving and piles of once neatly stacked towels, bedlinen etc. In addition, there will be various items of unknown origin and purpose long since dried out and most certainly forgotten about.

The airing cupboard in my house features my drying clothing on hangers and my housemate's dried clothing waiting to be sent away to be ironed.

In the airing cupboard of one of my mates is a kayak, misc climbing and outdoor gear, usually a tent and sleeping bags. He was thinking about removing the hotwater tank and boiler to give him more space. I suggested he may like to think that through first.

Al

Another way to dry the inside of your bezel is to run the incan continuously until the bezel gets really hot. Something like 10 minutes or thereabouts. Then unscrew the bezel, remove the lamp, and set the bezel/head on its side on a table and let cool for at least 30 minutes. Then install and repeat until there is no moisture seen on the inside of the lens.

Britt, I'm going to have to tentatively disagree about "Closeup the light while it's still in the "drying cupboard" ", because hot air holds a lot more moisture than cooler air, so even though its relative humidity is low (which makes it good at drying things), if you trap it in a space and let cool, then you will get condensation. You can see this if you take something out of the oven (like a potato or loaf of bread) and immediately seal it in an airtight container and put it in the fridge. When it has cooled, you will see drops of moisture clinging to the underside of the lid.

By letting the hot item sit in open air, you are letting that moisture get transfered out and away. The hot air will grab it, like a towel, and then will convect away and it will get absorbed into the room air.

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...I'm going to have to tentatively disagree about "Closeup the light while it's still in the "drying cupboard" ", because hot air holds a lot more moisture than cooler air, so even though its relative humidity is low (which makes it good at drying things), if you trap it in a space and let cool, then you will get condensation. You can see this if you take something out of the oven (like a potato or loaf of bread) and immediately seal it in an airtight container and put it in the fridge. When it has cooled, you will see drops of moisture clinging to the underside of the lid.


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That's a good point to consider, Jim. /ubbthreads/images/graemlins/smile.gif

However, the reason potatoes and bread out of the oven sealed in a bag produce condensation is because they have substantial moisture within them and which is still being given off as vapor which is trapped in the bag and condenses.

A flashlight or other small bit of equipment won't have any moisture content after it's been in the "airing cupboard" ( /ubbthreads/images/graemlins/grin.gif, Al) for a sufficient time.

The air in my water heater closet is very dry, much drier than the air in the rest of my bunker.

I suppose one has to figure out how best to apply the principles in one's circumstances.

Britt

Interesting. I've never had a moisture issue with any of my A2's. I do keep one in the car at all times. It stays in there all year long, during the hot summer and cold winter.

Britt,

Yeah. I thought of that as I was driving home today. I know one thing for sure:

1. Hot air can be "drier"--i.e. have a lower relative humidity--but still have a greater absolute moisture content, than cooler air.

2. When surrounded by an impermiable barrier, this moisture will be forced out of the air if it cools past the point where the RH gets to 100 percent.

3. On the other hand, cooler air that is warmed up, gets "drier".

So, if you are CERTAIN that the air in your drying cupboard has no more absolute moisture than the air in the rest of your house, then it is fine to close up the light while it is hot. But if there is a source of moisture near the hot area (such as a water heater, maybe ? --honestly not sure--not trying to be snide) then the RH of the air could be low, but the absolute moisture content could be greater.

There are a lot of considerations and variables to get straight, and it's more or less impossible to say in general, but still, my point is just that if you leave the head/bezel open to the room air, any room air that gets in will actually warm up and have as low or lower an RH as the hot air inside. So it can't hurt, and if the hot air has a significantly greater absolute mositure content in it, then it could help.

I think that that's correct. But I don't know for sure. Whatever has worked for you in the past is probably the best thing to continue to do, and JorgeM can pick the method he thinks best. My way has worked for me so far, but that hardly means its the only way.

Try stickin it in a plastic bag with some rice? The rice should be sucking up the moisture. That silica gel found in packaging might also work?? I haven't tried this, but remember we used to keep rice grains in the salt shakers to keep salt running. Let us know wether it works /ubbthreads/images/graemlins/smile.gif

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So, if you are CERTAIN that the air in your drying cupboard has no more absolute moisture than the air in the rest of your house, then it is fine to close up the light while it is hot. But if there is a source of moisture near the hot area (such as a water heater, maybe ? --honestly not sure--not trying to be snide) then the RH of the air could be low, but the absolute moisture content could be greater.

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Yeah, it's dry alright, however one describes dry. I've kept a pistol hanging from a hook in there for years.

Remember, it doesn't actually get "hot" in there. More like warm. The thermometer reads 81 degrees F. right now. That's 17.6 degrees cooler than me.

YACHRHMV (Your Airing Cupboard's Heat & Relative Humidity May Vary) /ubbthreads/images/graemlins/tongue.gif

You guys, just freaking get out of the humidity!!!

Averages about 30-40% here, less in the winter!!

No problems with fogging here!!!

Bill

90-100% relative humidity here, all year round.

If you are coming to visit from a place as dry as Bill's, or returning home, the first breath you take when you get off the plane can almost feel like you are actually sucking down water. Ask me how I know. It gets better after a few dozen breaths. If you don't roast to death first /ubbthreads/images/graemlins/grin.gif (or is boil?)

Anyway, doesn't help the lights much. The Roar of the Pelican had a really bad fogging problem which did cause a little bit of water damage to one of my reflectors, and cost me a bulb when I popped it while trying to get the fog out.

I eventually found a solution - unscrew the Borofloat lens (ROTP is housed in a Mag 4D), POINT THE LIGHT AWAY FROM YOU (especially crucial because if the bulb pops, you absolutely do not want glass headed for your face at high velocity), light it. Run it for a minute to let whatever the heck is in there boil off and bring the head assembly up to normal operating temperature. You must run the light hot with the bezel off to dry it out.

Very carefully screw the lens and holder back onto the thing without turning off the light, and without putting your face or other body parts in danger. It can be done, hold the assembly by the edges.

Fogging problem goes away for good... No hot air cupboard required and it works even here with all the humidity. The light has never fogged again, no matter how long I run it.

Also, a big thank you to js for his help with those little problems when I first mentioned the popped bulb/fogging thing. /ubbthreads/images/graemlins/smile.gif

Kevin,

Good idea! And good that you mentioned to be careful of the possibility of a lamp explosion.

Although, on some lights, the bezel or lens is what holds the reflector in place (or they are one piece, such as with the A2), and so it would be more problematic in those cases, but still, good idea.

You can also use a laboratory desiccator -- a glass container with a shelf at the bottom below which you put chemical desiccant. There are vacuum desiccators too, which require a pump. These can usually be found on eBay. Desiccants are easy to find a sporting goods stores. Most can be "recharged" in the oven.

You can improvise by pouring desiccant in a glass pot, putting your light parts on cardboard, and sealing the lid with tape. Do that a few times though, and you'll see how a desiccator is worth it.

Scott

[edited: I swear my spelling was ruined by MS Word during undergrad!]

My dehumidifier - used to dehumidify bits of computer which had been sitting in my cupboard for months - then the roof leaked and everything got SOAKED.

Take one container (large enough to accomodate whatever you're drying, and make sure that it's capable of being sealed. Tupperware boxes work well for this on a small scale).

Fill it 1/3 full with dried rice grains. Insert item to be dried, close lid, put somewhere warm, wait.

The rice will dehumidify the air inside the container, and the water will evapourate from the item, getting trapped in there. Simple, but it seems to work well. Putting a cheap humidity meter in there can give you an idea how well it's working.

We have laboratory desiccators in our chemistry lab. I think I'd get it in the neck if one of the labcoats caught me putting flashlights in them!
We also have a number of ovens running at various temperatures and conditioning rooms running at various temperature/humidity specs for testing.

Al

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js said:
Kevin,

Good idea! And good that you mentioned to be careful of the possibility of a lamp explosion.

Although, on some lights, the bezel or lens is what holds the reflector in place (or they are one piece, such as with the A2), and so it would be more problematic in those cases, but still, good idea.

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Possibility?

It's quite loud, you'll hear it when it happens /ubbthreads/images/graemlins/tongue.gif

Not too worried even though it happened to me because I did take these precautions and the other half of the glass shot directly away from me, thus putting me in no danger at all.

Drying the E2e-SG wasn't as easy, basically I ran it hot, turned it off, removed the bezel and tried to dry it that way. So far, so good.