I have a walk in gun vault that is all concrete and it kind of humid in it. I bought a 70 pint dehumidifier for it and I'm wondering what the ideal humidity setting is for proper gun storage to prevent rust. The digital readout on the dehumidifier ranges from 35% to 85%. Thanks for any input!

I leave mine on 40.

The drier the air the better. 0% humidity is the best possible condition for firearms.

Thanks guys! My next question is my vault is pretty small only about 4 feet wide by 10 feet deep and is about airtight when the door shut. Is it safe to leave the dehumidifier running 24 seven in such a small space?

Sorry guy, but that's not correct.  Too low humidity will crack wooden stocks eventually.  I shoot for 40-50% humidity in my safe.

We're talking about rust.

It will generate some heat, especially if it has to run a lot (if the humidity in the room would otherwise be very high at some times of the year), but it will cycle on and off to maintain the humidity you set it at. In a room that small, I wouldn't think it would need to run constantly, so I'd imagine it should be just fine. Try it and check on it from time to time and see how it does. With mine, it hardly runs during certain times of year, then runs quite a bit during humid times of the year. Mine's in a bigger room though, so it probably runs more than yours will.

Assuming none of them have wood stocks!

I have a lot of wood stocks as well as plastic and steel parts. I guess I should say I want the perfect humidity level to preserve all guns wood, plastic and steel parts.

So you think 35% would be a good setting or is that to low?

I run mine at 40%.  Seems to do the trick.

The NRA Museum keeps their display cases between 40%min to 50%max- IIRC. I asked once.

That would probably be fine. Remember, the sensor on the dehumidifier is sampling air that exits the unit, not the room as a whole. I would not depend on it. Instead, place several hygrometers throughout your vault to get a better sense of the overall environment and adjust your dehumidifier controls accordingly.

Personally, my dehumidifier is a bit undersized for my "man cave". However, most of the year I do not need it. When I do, I let it run full bore until the weather changes. My indoor Rh varies from twenty something percent  in Jan/Feb to forty something percent in the dog days of August. I have never had a problem with rust or damaged wood.

ETA- Good guns are built pretty hearty to begin with. A good rule of thumb is that if the environmental conditions are comfortable for YOU then it is probably OK for your guns. If it feels humid to you then you probably need to do something about it. Also, keep a thin coat of oil on the metal and use a good wax on the wood every once in a while.

I just got a mini split system installed in my gun room yesterday.  I'm wondering what to set it on?
It stays around the 50-70 degrees in there buy Relative Humidity stays around 70.  I keep my stuff well
oiled.  But now what do you set it on that will keep the Humidity in that 50 range?  

Currently I have the heat on 70 in the room.

NRA museum stores their firearms at 50% relative humidity which is low enough to prevent rust but high enough to not dry out and crack wood stocks.

If your safe is full of AR's and Glocks (no wood stocks) then you'd just want the lowest humidity you can possibly get.

My concrete gun room is 16x16. I keep mine at 50% and everything seems fine.

I got a few cracked stocks with my dehumidifier set at 35%. I now run 45% with zero issues for about 5 years.

Thanks for the heads up! I'll reset mine for 45%.

You're better off buying DampRid. I use DampRid in every safe and firearm storage location. Cheap and refillable. Last 3 to 4 months. Most hardware store will carry it. If not you can buy it online. A refill bag should last for 1 to 1.5 years.





https://www.google.com/search?q=DampRid+&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a&channel=sb





http://www.amazon.com/DampRid-FG50T-Hi-Capacity-Moisture-Absorber/dp/B0029EGUNG/ref=sr_1_1?ie=UTF8&qid=1429658498&sr=8-1&keywords=damp+rid+moisture+absorber





http://www.amazon.com/Barr-FG30K-42oz-DampRid-Refill/dp/B000ZZWSVY/ref=sr_1_7?ie=UTF8&qid=1429658498&sr=8-7&keywords=damp+rid+moisture+absorber
 

I'm using crystallized kitty litter. Got that tech tip from the board.

IF the OP is concerned about heat build up, put it on a timer.  You're pulling moisture out of the air in a fairly air tight room, generating heat running the unit. Sounds like you're putting the moisture back in the air with the heat build up. That water has to go somewhere until you dump it.

Exactly how much water are you dumping in a 24hr period?