Humidity; friend or foe?
A few months ago, I purchased a safe for my airguns. I also purchased a goldenrod stick sized for the size of my safe.
Whether or not the goldenrod works, it got me thinking about humidity in general.
My acoustic guitar likes humidity in the middle range to be happy. Based on this, I would think my really nice black walnut stocks would like some degree of humidity too. This is where wood and metal are at odds. How do I ensure that my rifles are most happy? What is the middle ground? Will oil or wax supplement for humidity when its comes to wood?
Well, I'll speak to this from three worlds. As well as being an airgun, and shooting in general, enthusiast, I'm also a trained luthier, and a woodworker. I work mostly on violins and violas as a luthier, and build furniture as a woodworker. You're talking apples and oranges here. Kiln dried hardwood is quite stable under many conditions. You can equate a lot of furniture wood with gunstock wood. once it's dried it really doesn't do much. In really dry conditions, the joints on furniture, and thing like flooring, can open up due to shrinkage, but it would be very rare to have the boards themselves split. You're talking about unhumidified heated air, like from a wood stove, where the humidity levels would get to the 10-20% RH level. Generally, the minimum humidity for your house and furniture should be 30-40%.
Instruments are thinner, usually quarter sawn wood. The thin top is attached to more rigid ribs, and any shrinkage of the wide top, with the edges restrained, could open up a crack. The hide glue used in violins (not so much in guitars) is also humidity sensitive, and can get brittle, and joints can open up in really low humidities. I usually try to keep instruments at 40-50%.
Really high humidity can cause glue joints to soften (special glue is used for the tropics). High humidity would be more of a problem with steel and rusting. Your golden rod should be working for you. It works by raising the temperature of the air in the cabinet. The air would contain the same amount of moisture, but as you heat it, it can hold more moisture, so the RH goes down.
I'd say that you can go dryer with the guns than instruments, but with either, don't get them up into really high humidities for long periods of time.
As a gun stock refinisher, and owner of many wood stocked AG's & FA's, I find that my stocks dry out in the winter due to low humidity. Therefore, I treat them once or twice a year with a quick rub down of boiled linseed oil. It rejuvenates the wood, and preserves it's beauty.
However, on the flipside, low humidity is steels best friend. I also treat my steel gun's using a silicone impregnated cloth, after every use, and several times a year for the gun's that don't get used as often.
Both of the above treatments have kept my shooters looking great year round, no matter the RH level
My understanding is 45-50% RH is the ideal to preserve artifacts like guns. I like this to help keep tabs:
because I can see the RH of the room and the interior of the safe at the same time without having to look in there. If your safe is in a basement, keep in mind that the elevation of the probe (e.g., 1 foot off the ground vs 5 feet) will make a significant difference in the RH.
I worry much more about the metal than the wood. My safe is in the basement and I keep my probe about 15 " off the base of the safe. At that height, I like to see RH no higher than 55% in the summer, and it can go as low as 40% in the winter. I'm fortunate that my safe is inside a small room where I can have a dedicated dehumidifier to keep things less humid in the summer, because I find the safe warmer thing ( I use a PEET dryer) can't always get things low enough. If that's not practical, then some desiccant in the safe would be the way to go.
And, like Scott, I quickly wipe down my guns with a little gun oil every single time I handle them before I put them away. I prefer a flannel cloth with a light mist of rem-oil but, regardless of what you use, it takes 10 seconds to do it and is a small price to pay for peace of mind!
Thank you all for your replies.
I read that you all have different solutions for this potential problem, albeit not all that different with outcome. I like the idea of using linseed oil to protect the wood. I have been using Ballistol liberally as cure-all for both my wood stocks and the metal work.
I use battery operated temperature/humidity sensors in my home with good results for the past few years. I plan to buy another from Amazon to use in the safe to monitor conditions. I have my safe in the garage (not ideal) which is not insulated, nor heated, or AC. I just moved to the south, and the Summers are very humid here. I guess I will have to uses a little trial and error as I begin to store them. For now, they are in individual cases with packs of desiccant.
Humidity's not so big a deal with stocks as it is with metal. Rust is the main concern. I've been lucky using dessicant packs made for gun safes and lockers, a light wipe down with Barricade followed by RIG, and a silicon impregnated gun sock or Bore Store. (One of the big time collectors in my gun club swears by the latter.) Most gun stocks are made from wood with a low amount of movement caused by humidity, which stands to reason, so stocks can take a fair amount of moisture. On wiping down with gun oil, there are so many better products available now. One of my old Shooters Bibles has a reprint of a 1930's article which advocated going over a gun with a well-oiled rag. If you visit gun or pawn shops selling used long arms, you are bound to see old shotguns where the stock wrists are darkened or even blackened from the oil slowly running down and leaching into the unfished grain behind the receivers. Another reason a lot of guys store muzzle down.