Humidity in the home

[billhammond]

Here in Minnie-Soda, Marty advises that acoustic guitar owners need to pay attention to home humidity between when the leaves fall off the trees until they are back in full green bloom in spring.But this fall has been unusually dry, with my living room hygrometer reading 35% relative humidity today.

So it was well past time to clean up my Essick humidifier, truck over to Menards for some filters and get the thing fired up again.

I am sure I will sleep better than I have in the past week or so, constantly waking up and having to rehydrate.

[Cornflake]

What's humidity?

[xyrn]

Terry said I don't need to worry too much, with a Kennedy, until the RH is below 30%.
Given the fact that the wood was stored and the guitars were built in "relative" dryness.

[TKennedy]

I usually try to keep my shop around 40%-45%. Above 30% should be safe, might lower the action a bit but below that the red zone starts. Marty should chime in but from what I have seen around 20% is a setup for cracks and bridge lifts as well as sharp fret ends.

New guitars seem more sensitive in the first couple of years and tend to stabilize as the wood gets cycled a few times.

I try to build with tops that were cut many years ago and allowed to season by being exposed to cycles of heat, cold, and high and low humidity while stickered up. Walter Lipton at Euphonon has wood like that. Some cut 25 years ago. They are by far the most stable. That is not always possible, especially with woods like Lutz spruce and the Adirondack I get. It has typically been cut within the last few years and either air or kiln dried. The humidity meter says less than 6% but it has not been cycled and is less stable.

I've got an old garage sale oven and bake these tops at around 200 degrees for a couple of hours stickered up. That takes them down to zero and then you allow them to re-humidify for a few months in the shop. I think it helps make them more stable. They actually lose weight and never fully regain the initial weight after re-humidification in the shop.

Now there is a new thing called "torrification" where they use high heat in some kind of vacuum or inert gas atmosphere. The guys at Old Standard Tonewoods where I get Adi gave vague reference to their "special process" for Collings but were pretty tight lipped.

It might be this guy who sells Old Standard tops that have been "acoustically optimized" by a secret process.

acousticoptimization.com

As in medicine it's usually best to give the "latest procedure" a pass until it's been out in the real world for a few years.

[coachdoc]

Don't be the first. Don't be the last.

[jdd2]

Even if this is way off, it's still okay:

[drlj]

Heat has been coming on here, but not steadily. The indoor humidity is still around 45% but I will be getting the case humidifiers ready pretty soon.

[Deleted]

I also try to keep the shop at 40%. I'm planning on adding another humidifier to the house, with two they will each work less hard. I'll keep the shop at 40% and the house at 30%.

Most of you that will need to humidify this winter will find it much easier to humidify your house to 30% and use guitar case *humidifiers. This way you can play guitar for a while without drying it out too much and it will hydrate when returned to it's case. Having your house at 40% will invite water to condensate on the windows.





* You'll find these in the gift shop after the show.

[Marshall]

The heat has been on-and-off for a few weeks. It got down in the 30s last night, so the furnace is firing every once in a while. I already put a new filter in the whole-house April-aire a couple of weeks ago, and cranked the dial up. The humidistat in my office room says 42%. It'll get down to as low as 30% in the dead of winter, as the unit is not sized for the house. It's the biggest single unit I could get at Home Despot. But still not sized for the house. Most homes like mine have 2 systems. One for upstairs and one for the main floor. I've just got one big puppy cranking the palace.

But last weekend I pulled out the Oasis soundhole humidifiers and syringed them full of distilled H2O, and dropped them in each of the 4 acoustics that reside here. I'm most concerned about Luke, the new Nick Lucas inspired model. This is it's first winter season under stress.

[epaul]

Keep an eye on your Oasis, Marshall. I have had two develop leaks. No guitar damage, fortunately. Others have been less fortunate. Consumer Reports/guitar division* has pulled their recommendation of the Oasis humidifier due largely to their potential to develop leaks (lesser factors involved all the putsiness involved with maintaining them (syringing in distilled water weekly, replacing the absorbent crystals, regular leak checks).

I now just use the Consumer Reports/guitar division top-rated Marty Soapdish [soapcase] System. The Marty Soapdish [soapcase] System keeps the guitar case safely humidified, and a safely humidified guitar case will keep anything within the guitar case safely humidified. If the case is humidified, there is no reason to place a moisture containing device inside the unfinished guitar body, none, as there will already be safely humidified air inside, and all around, the guitar.


*I run the CR guitar division out of my basement office. We are, as yet, unaffiliated, or even acknowledged, by CR (despite several emails requesting funding and the possibility of some back salary).





/

[Deleted]

Funny story about humidifiers.... When I moved to Kuwait, I brought a Kyser and one of Marty's sponge boxes for my Schwab. It stays in its flight case most of the time, so the humidity in there is fairly stable. The case is darn-near air-tight. (I think the ads tout that it is waterproof.)

However, I didn't being a humidifier for my reso, foolishly thinking, "Hey, the body is metal, so why do I need a humidifier?" Well, doofus, you need one because, No. 1, you're living in the desert and, No. 2, the neck is wood and there's a big honkin' piece of wood that runs the length of the body. So I improvised with a sponge in a zip-lock bag that's got holes cut in it.

So one of my missions on my recent trip to England was to get a guitar humidifier. I wanted a Dampit, thinking I could drop it through one of the reso's f-holes. I stopped in a guitar shop in Watford, asked what kind of humidifiers they had, and the guy looked at me like I was crazy. It was raining out, and he remarked, "We really don't need guitar humidifiers around here."

"Not even in winter, when folks turn their heat on?" I asked.

"No," he said, still looking at me like I was crazy.

Over the next couple of days, I hit three more guitar shops in two cities. They carried a pretty good inventory of guitars, but none had a humidifier. I asked one shop owner if people humidified their guitars in the winter, and he said those who do usually just order one online and get it the next day. (Perk of living in a small country....)

[Hobson]

Since the evap cooler has been shut down for the season, I'm keeping an eye on things. My soundhole humidifiers are sponges inside holey baggies.

Curious about the distilled water. Is that to protect the wood from chlorine or to keep the Oasis from clogging up or something else that I'm missing? (No chlorine in our well water and so far the baggies haven't clogged.)

[david]

Opposite problem here in Portland Oregon. Humidity in my house for the last few days is running 65 to 75%. I am on the verge of buying a dehumidifier.

[epaul]

The minerals contained in most tap water will eventually clog the pores of the fabric the Oasis depends on to transfer water vapor. The minerals in tap water will also, eventually, mess up a sponge-based system. But, it takes so long and the sponges are so cheap, I don't worry about it. But, if you want your sponge to last as long as spongely possible, use distilled water. Or, buy a new sponge every couple years. My farm water is loaded with minerals, my city water has much less.

Hard water is water with lots of minerals in it. Rain water has no minerals, (just various pollutants and cloud grime). Softened water can be darn near anything, but, if run through an ion exchange unit (water softener), some minerals will be removed and replaced with sodium and other minerals will still remain. Whatever it is, it isn't distilled water and isn't a substitute. If you have a well-maintained reverse osmosis system, you are likely good to go. It may not be fully distilled (or it may be), but it will be good enough. If the unit is maintained (a pita).

[Marshall]

Oct 23, 2014 8:56:09 GMT -5 epaul said:

Keep an eye on your Oasis, Marshall. I have had two develop leaks. No guitar damage, fortunately. Others have been less fortunate. Consumer Reports/guitar division* has pulled their recommendation of the Oasis humidifier due largely to their potential to develop leaks (lesser factors involved all the putsiness involved with maintaining them (syringing in distilled water weekly, replacing the absorbent crystals, regular leak checks).

I've had some of these Oases for 5 years. Never changed no stinkin crystals. Never gotten no stink leaks. I always use distilled water. No muss no fuss. They hold a lot of water quite nicely (so far).

[Marshall]

Oct 23, 2014 11:01:51 GMT -5 Hobson said:

. . . , Curious about the distilled water. Is that to protect the wood from chlorine or to keep the Oasis from clogging up or something else that I'm missing? (No chlorine in our well water and so far the baggies haven't clogged.)

Distilled water doesn't leave a residue behind when the water evaporates. With an Oasis, hard water would leave a residue that would clog the system. With a sponge system, you can just rinse out the sponge and that will wash away the old residue. Of course, there will be a small amount of new residue each wet-drying cycle. But there's no build-up, as you rinse it out each time.

I have a Dampit in my junk box. Those leaked inside my guitar. That's just a skinny sponge inside a long perforated rubber tube. The tendency with sponge systems is to overfill the sponge, so some water will want to drip outside the sponge. Marty's system is nice. I think the soap dish holds water better, except there's holes drilled in it, right? I suppose you can drill the holes in the top of the dish. But the dish can flop around in the case if you're carrying it around.

I think the Oasis holds more water. And they get limp and shrivelled, showing you when you need to fill it again.

The Kaiser system is a sponge in the soundhole. They're fine, but the moisture is a) only in the inside of the guitar, and b) the sponge is small and doesn't hold much water.

My problem with sponges is I always over-wetted them, so there can be drippy problems. The Oasis gives me an exact level to fill it to; then the cap seals it shut. No spillage, unless you damage the casing. And I haven't broken one yet.

[PaulKay]

I keep three "so called" whole house humidifiers running all winter. One in my study where I keep some guitars and the other 2 in the basement which run continuously to try to keep everything at 45%. The thing I really hate is having to refill the damn things every single day during the winter. I also keep 3 digital hygrometers around the house to make sure these humidifiers are working towards their setpoint. Just in case they don't work like they should. Also I have to cover the windows with plastic, because the humidity interaction with the poor window insulation causes ice buildup on the window frames. I giant pain in the butt actually. But better than letting 13 guitars dry out and crack.

[Doug]

When it was young my D-28 hung on the wall behind the wood stove for a couple of years.  I think as a general rule we over worry about humidity.  I do worry about it as far as sound goes but not as far as safety for the guitar.  Living in FL where inside humidity with AC running 24/7 is 80% made the D-28 sound like it was filled with wet socks.  Sounds much better dryer.  

[Deleted]

Oasis humidifiers work quite well, the only commercial made one that I say that about. They do have two weaknesses 1)never fly with one in your case. The loss of air pressure will burst it. 2) Fill them gently, forcing water in can rupture the seam.

They DO need to be recharged every year. The gel recharge kit is about $5 and will do 4-6 recharges. When recharging rinse the Oasis out first, very gently, then put 1-2 scoopful of gel crystals in and refill with H2O. Scoop is supplied with kit.

About time for me to start making humidifiers.

[Marshall]

When the spring arrives, we recommend that you remove the humidifier, wash all of the crystals out, and leave the cap loosely on the humidifier. If you do not remove the crystals and loosen the cap, the humidifier will shrink up, dry up and the crystals will stick together. In the fall, it is easy to damage the lining of the humidifier when trying to restore it to shape. The lining is only 1/1000th of an inch thick and can be damaged easily if it sticks to itself and the crystals, when the humidifier shrinks up and dries up if the lid is left on tight.

Interesting. I've been doing it wrong. But I've never had a problem. I see the reason for new crystals is they want you to wash out the old crystals every spring; not because they wear out, but because they'll stick together when it dries out.

And the crystals do nothing, anyway, except control the flow of water if you have a break. It's the water-vapor-permiable (but water impermiable) membrane that does all the real work. And if you let the thing dry out the membrane might attach itself to itself when it dries and damage itself when you re-hydrate the thing.

Maybe I'll order a couple new ones and treat them better in the future.

But the ones I have have worked wonderfully so far.