Thread: Humidity control

I have wrapped a home brew heating belt around the bottom of the safe. It works good and raises temp in the safe and whole closet by a few degrees to negate few point on my gunmetal.

Although these are designed to be left on all the time, I wonder if the square edges of the safe could present a problem?

Appreciate your thoughts.

It draws 30w

My thoughts are that it should be ok as long as you check it often and don’t knock it with anything hard.
But most of the heat will be going into your wardrobe which may not be a bad thing. Have you checked the temp inside the safe I’d be interested to know how warm it gets?

What did the hygrometer show before and after?

I just drilled a hole in my safe and installed a free hanging 230 v light socket on the end of the cable with an INCANDESCENT 15 watt light bulb. If not effective enough, increase the bulb's wattage, but it must be an incandescent bulb to produce the heat.
Failing that, a wardrobe heater, they range in wattages up to about 100 watts. Google "wardrobe heater"

Originally Posted by Kiwi Sapper

I just drilled a hole in my safe and installed a free hanging 230 v light socket on the end of the cable with an INCANDESCENT 15 watt light bulb. If not effective enough, increase the bulb's wattage, but it must be an incandescent bulb to produce the heat.
Failing that, a wardrobe heater, they range in wattages up to about 100 watts. Google "wardrobe heater"

Even the tower LED lights give off heat...but then what is the best temperature for the internal of the safe and what is the best humidity level to maintain it at?...without ventilation is there really any point of the exercise?

Originally Posted by mimms2

Warm air is capable of holding more moisture... being warm and wet is no use, it needs to vent.

As to the bending of the fillament wire, i should think they're reasonably protected, however bending it it the same place repeatedly would cause metal fatigue. I imagine the result would be "stop working" rather than "burst into flames".

Or shorts out and makes the safe live.

Similar idea to the golden rod, but cheaper, so good idea! What about running wires through a hole and fitting it to the inside wall of the safe? Would be more protected and do the same job. Or get some copper pipe and 90° fittings, and run it through that to protect the element and still transfer heat to the safe.

Regarding humidity vs rusting - I'm shaky on the concept, but unless the safe's truly sealed (basically a rubber gasketed airtight box, which safes usually aren't) moisture will always equalize across an area relative to the air's moisture holding capacity which is controlled by temperature, so I think the purpose of the safe heater is to warm the guns and entire inside safe which should stop condensation and rusting that way? I think most rusting happens when temps drop and moisture precipitates out of the air and condenses onto cold surfaces, so the goal of a safe heater is to maintain a stable environment and keep the inside of the safe, and more importantly the guns above a "normal" condensation temperature rather than try to control moisture itself. A safe heater in a sealed safe would be a steam box, so cause rusting, but a safe heater in a normal safe should in theory have enough air exchange to not cause that. That's the theory at least... whether or not my understanding of condensation and humidity causing rusting is completely correct is another matter.

Kiwi Sapper's lightbulb heaters work well, and has the added benefit of allowing you to see in what are usually very poorly lit enclosures. Just put a guard or transparent shield over the bulb or you'll smash it moving rifles around :p Safe heaters do work, so something must be correct in the theory.


Your alternative is to control moisture by sealing the safe, then sucking the moisture out with a dehumidifier. It's what makes more sense intuitively, but relies on a sealed container and ability to monitor and control humidity constantly. Plus you could crack wood on stocks if you drop your humidity too low, which a dehumidifier certainly could do in a confined sealed space.

A container of Damp Rid from the DIY store will take care of any moisture in the safe and is a good indicator of what moisture there was.

Good feedback, thanks. It's definitely warmer inside the safe as is the whole wardrobe.
The warmed air does carry more moisture. There are a few holes in the safe as well as the door being far from airtight, as is the wardrobe door. Its not booking a jug humidity. The increase in temp negates the dew point on metal.

I think ill do a low wattage light bulb inside if not satisfied, or get a rod thingy from workshop innovation.
My wife thinks ill burn the house down

How would modern rifle scopes with their fancy electrics handle the higher humidity in a heated safe...I imagine an older scope could fog up if removed from such a warm environment and taken out into the cold outside air.

I know from empirical experience (anecdote) that the light bulb inside works.

Originally Posted by canross

Similar idea to the golden rod, but cheaper, so good idea! What about running wires through a hole and fitting it to the inside wall of the safe? Would be more protected and do the same job. Or get some copper pipe and 90° fittings, and run it through that to protect the element and still transfer heat to the safe.

Regarding humidity vs rusting - I'm shaky on the concept, but unless the safe's truly sealed (basically a rubber gasketed airtight box, which safes usually aren't) moisture will always equalize across an area relative to the air's moisture holding capacity which is controlled by temperature, so I think the purpose of the safe heater is to warm the guns and entire inside safe which should stop condensation and rusting that way? I think most rusting happens when temps drop and moisture precipitates out of the air and condenses onto cold surfaces, so the goal of a safe heater is to maintain a stable environment and keep the inside of the safe, and more importantly the guns above a "normal" condensation temperature rather than try to control moisture itself. A safe heater in a sealed safe would be a steam box, so cause rusting, but a safe heater in a normal safe should in theory have enough air exchange to not cause that. That's the theory at least... whether or not my understanding of condensation and humidity causing rusting is completely correct is another matter.

Kiwi Sapper's lightbulb heaters work well, and has the added benefit of allowing you to see in what are usually very poorly lit enclosures. Just put a guard or transparent shield over the bulb or you'll smash it moving rifles around :p Safe heaters do work, so something must be correct in the theory.


Your alternative is to control moisture by sealing the safe, then sucking the moisture out with a dehumidifier. It's what makes more sense intuitively, but relies on a sealed container and ability to monitor and control humidity constantly. Plus you could crack wood on stocks if you drop your humidity too low, which a dehumidifier certainly could do in a confined sealed space.

As he said to begin with keeping the contents above dew point is the primary aim. Corrosion so much less likely without a continuous film of water.

I’ve just used dam rid container since day one, works good.