When I got my safe back in 1996 ,there was a product called a (Golden Rod) its a just a heater about 10 or 12 " long that is mounted under the bottom shelf,most safes I believe have a small access hole somewhere to run an electric cord.If not a hole will have to be drilled to access electric.
Ok i finally got one at Tractor supply where I bought the safe. It is a Cannon brand electric 12" rod. I have my safe set up with all guns on left side and ammo/accesories on the shelfs on the right side. Where should I mount the rod, i am guessing the left side but will it hurt the guns that close to them. Also there is no control on it, just plug it in and let it go. What temp/humidity should it be kept at? Right now it is 73ºF and 43% humidity. Thanks!
Just put in in the bottom and let it go. It will simply keep your safe a couple degrees warmer and that's all you should need to keep the humidity in check. Touch it when you're in the safe to make sure it's still working. If you're still unsure, place a desiccant pack with the color coded status label on a shelf and watch it as well.
Firearm and furiture museums reccomend a humidity level of 50% to keep the wood from shrinking. Bone dry for the metal but you would get checking or cracking of the wood.. No man wants a "shrinking" problem....loll
Before turning the heating rod loose in your safe, pick up an AcuRite digital humidity and temperature monitor for under $10. You want 45-55% humidity. Too little, and, as 1straightshot said, you dry out the wood, too much and you get condensation on the metal and swelling in the wood. I've found that despite living in a coastal, high-humidity region, monitoring the past year and a half, my vault never goes above 52% humidity. That $10 saved me a lot more; I was expecting to need to buy a large dehumidifier.