Humidity and hygrometers

[Stefan]

Long story short.

I have been thinking about the humidity problems since I bought my Martin D16-GT last fall, so I finally bought a hygrometer to check the humiditylevels in my apartment.

It wasn´t a very expensive hygrometer. It´s was about $20. I put it on the wall where I keep my guitar. To my surprise it shows only 14% HR!!!
When I bring the hygrometer to another room, just a few meters away, it shows 30% Can this be true? Can it really vary that much? I decied to keep the Martin in its case along with a homemade humidifier .

[superchicken_VI]

As a cigar guy who has had a walk-in humidor before and now uses a buffet converted into a hudidor, I've learned a lot about humidity to protect my investment.

Is your hygrometer a digital or an analog model (with a needle)? If it's digital, it's likely to be within a few points of accurate. There's a salt test that can help you calibrate your hygro, but if it's off by 5%, that close enough for guitars (but not for cigars--that 5% is enough to ruin them). If it's an analog model, throw it away (or use it for decoration only) and get a digital as pictured in your link. The analog types are rarely accurate.

Depending on the type of heat you have in your home, A 15% change in humidity between two different rooms with different heat isn't that surprising to me. With the heat off in my house, my kitchen has about 10% higher humidity than my guest room. I'm still in the upper 30s and lower 40s in the guest room (with the door closed), so it's no problem for the guitars that are in there.

However, if you have only 15% where your guitar is, I'd recommend doing at least what your link shows. For cigars, we use Oasis wet florist foam (any florist's shop has it, and you need the wet kind for holding cut flowers and water) with a mix of Propylene Glycol (PG) and distilled water. This keeps the humidity at 70%, and the PG will actually pull humidity from the air if it gets too moist. You could cut a strip and put it in a perforated tube, and it will stay moist longer than a sponge and be less messy. If you use a sponge, use steam-distilled water, as tap water will cause mold to grow on the sponge and possibly your guitar.

Personally, I'd use a room humidifier if you want to be able to keep the guitar handy and keep it safe. There are several models with built-in hygrometers that will run just enough to keep your room as you want it. Here, I use a Moist-N-Aire for my cigar collection. It's a little pricy at around $140, but I've had it for 8 years with no problems.