Our Advice, here in Minnesota, where the inside of a house during the winter gets to about 5%-10%, which is to say, dryer than Death Valley, is a two step process. First of all, most important, the thing you absolutely MUST do, is to DO SOMETHING. You already have this covered, but you would be amazed at how many people do not. We see somewhere between 500-600 guitars a year with humidity related problems. Many if not most have cracks, even more have fret ends protruding, and all of them have sunken tops, which of course lead to low action, and that means buzzing. Oh Joy!!!
So, what we really want to see our customers do to keep their guitars in good shape is as follows. First of all, throw away the Dampit, and get a Kyser Lifeguard. The Dampit is next to useless for a guitar. They simply do not hold enough moisture. The Lifeguard is a larger sponge, and it holds the moisture where it is needed most, in the body. This is particularly important if you keep them on stands. But you should not keep your guitars on stands during the winter. Keep them in the case, and in addition to using the Lifeguard, you should also either use a second Lifeguard up by the headstock, or (even better) use a soap dish humidifier. These are simple to make, and cheap to boot. You go to Target or Walgreen’s, or where ever, and get a plastic travel soap dish, the kind with a cover, and you drill some holes in the top. How many and what size is not important, but on the ones we use at the shop, I drilled nine 3/8 inch holes, because there where nine little bumps on the cover, so I just drilled them out. But there is no reason for them to be like that, as long as there are some holes. Next, you cut a sponge to put inside the soap dish, put it in, and keep it wet. That is all there is to it. Keep this in the case, up by the headstock (I have one customer who put some sticky back Velcro on the back of his, so it would not flop around the case. Good idea).
If you MUST keep them on stands (I do), then you must insure that the humidity in your room during the winter is between 45%-50%. If you keep it there consistently, then on the days when the humidity crashes (such as when it gets really cold, and you are heating the air more) you will only go down to the low thirties, and you will still be OK, if it is only down there for a short time. This is only really a concern during the winter, unless you live in the desert. The basic rule of thumb is, when you turn on your heat, start humidifying your guitars. If it is easier for you to just humidify them all year, go for it. You will not hurt them, unless you are pouring a bucket of water into it. In order to keep my humidity in the proper range, I run a humidifier on my forced air furnace, and I put another 20 gallons a day into my room. I change the filters on my humidifier once a month, when they recommend once every three. And I have to carry 20 gallons of water to my room every day.
As I said, we fix at least 500 guitars a year with humidity problems of one sort or another. At least 300 of them are cracks. If, god forbid, you ever do develop a crack, ask the repair person how they are planning on fixing it. If they say they are going to splint it, go somewhere else. We have been doing this in the WORST environment for guitars in the world for more than 30 years. In the last 25, we have not splinted a single crack. It is a lousy repair, it looks bad, and it is more expensive to boot. Don't do it. Find someone who will take the time to aggressively humidify the guitar, and then simply glue and cleat it. My sister, who I love, has zero ability to take care of the guitar my father built her when she was thirteen (in 1983). It develops cracks almost every year. This year, it had a side crack almost 3/4 of an inch wide. We humidified it for about two months before we worked on it, and that crack was completely closed. We had to realign it a little, but that is easy. She has agreed to keep the guitar at my place during the winter from now on. Also, cracks should be fixed ASAP, as the wood oxidizes, so the glue won't stick as well, and dirt gets in the crack, so it won't look as good.
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"Cowards can never be moral."
M.K. Gandhi
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