Is 64 % Humidity Bad?

[Robin, Wales]

Ooops!

[6L6]

I think WAY too much worry about humidity exists in the acoustic guitar world.

If you have a guitar made of wood, remember that it once was a tree. Trees are designed by mother nature to survive all kinds of humidity and temperature changes as well as the other elements.

Now that doesn't mean to leave your guitar in the truck of your car when it's a 100 degrees outside. Just be sensible and your guitar will be just fine.

[Dru Edwards]

I wouldn't be worried with 64% humidity over an extended period of time, although the guitar wouldn't sound it's best ... that I would notice.

[saxonblue]

I think I'd be more concerned about prolonged exposure of salt laden air to the tuners etc. unless you've taken specific steps to mitigate that.

[jim1960]

Originally Posted by rmsstrider

Will prolonged humidity at 64% cause any problems or am i just being paranoid?

Yes, prolonged exposure to that humidity level is going to cause problems to a solid wood guitar. The most immediate change will be the tone sounding muffled. After that, wood starts to expand. The top will swell, braces will swell and may start to loosen.

Will this happen to the same degree to every guitar? No. Some will handle the humidity better than others. The problem is, you don't know if your guitar will handle it badly until the damage happens.

So what can you do?
1. You can up your dehumidifying game. That may be hard to do on a boat, but if you have room, perhaps a well-constructed and well-sealed storage box could be made to hold additional dehumidifying agents so that exposure to high humidity would be limited to playing time. Perhaps something as simple as an oversized guitar case could suffice.
2. If your guitar isn't too expensive, you might just treat it as a beater and accept that damage may occur and at some point the instrument will be firewood. As you already have a CF guitar, you have the best kind of instrument for your living conditions. If the wood guitar isn't very valuable, I'd probably just play it till it dies and not replace it with another wood guitar but opt for the CF going forward.
3. If the guitar has value, you might sell it before it's damaged and the value is decreased. That would minimize your loss and if you wanted a second guitar for variety, you could put the money towards another CF guitar.

[Simon Fay]

You really don't want the relative humidity higher than 60% for an extended time. Even though really dry environments are the ones you need to worry about the most, high humidity can also damage the structure of the guitar.

It is erroneous to compare trees to guitars -- in a guitar, you are essentially taking a sheet of material that expands and contracts with humidity and locking it in a specified place/location (due to bracing and attachment to the sides). As this material expands and contracts beyond a certain point, you will obviously have problems. This is why we recommend that you keep a quality, solid wood guitar between 40-50% humidity if you can. At the very least, try and make sure your instruments are never exposed to humidity outside the 35% to 60% range for extended periods of time.

[rmsstrider]

Originally Posted by Earl49

Your paranoia is fully justified. Seventeen minutes of exposure to 64% RH will inevitably cause your guitar to explode violently. NOT!

Since most modern factory guitars were built at 47% humidity, plus or minus, you can expect some swelling of the top. In extreme cases top braces can detach or the bridge can peel up. Is there a pronounced rise in the action or a visible upward bow when putting a straightedge across the lower bout? If your boat is really at 64% RH in the cabin (not outdoors according to the weather-guessers on TV) then there is no need for Humid-Paks. Some silica gel packs to dry it out a little might be in order, but remove the humidity source first. Those packs give off moisture far better than they absorb it, despite being advertised as "two-way". The only way to really know is to keep a hygrometer in the cabin of your boat. Data is power -- to a point. The other question I would ask: is this is a new guitar seeing these climate changes for the first time? I worry less about my guitars that are ten years or older.

Well, I removed the humidity packs from the case and it now sits at a steady 57% humidity for past 2 days instead of the 64% with the humidity pacs.

[k_russell]

Originally Posted by paulzoom

I've had most of my guitars at 64% humidity (believe it or not that's with AC on) for a couple of months each year for the last ten years and have never had an issue. Not sure if that would be the case if it was all year long.

Similar situation for me. I keep two guitars at my summer cottage located about 500 feet from the Atlantic Ocean. The paduak has turned brown more quickly than you might expect. The guitars play and sound fine. The same two guitars have stayed at my summer place since 2010.

[Earl49]

Originally Posted by rmsstrider

Well, I removed the humidity packs from the case and it now sits at a steady 57% humidity for past 2 days instead of the 64% with the humidity pacs.

That is a good first step. Honestly I would not worry if my guitars lived at 57% RH all year 'round. They usually sound better at 40% than in damper conditions like the upper 50's, but no harm should come to them. A wood guitar dislikes highly variable conditions. If you can maintain RH in the upper 50's, you can adapt them (either with saddle changes or string choices) accordingly. I would not humidify at all until the conditions were steadily below 40% RH (my personal threshold is ~37% for most aged guitars and ~40% for new ones). Keep an eye on the action, fret ends, and top swelling or shrinkage. Then react accordingly.

Quality guitars certainly deserve attention to humidity for their long term health, but not obsession over RH and minor temporary changes..... just as eating a single bacon cheeseburger will not automatically cause heart disease.

[jim1960]

Originally Posted by rmsstrider

Well, I removed the humidity packs from the case and it now sits at a steady 57% humidity for past 2 days instead of the 64% with the humidity pacs.

That's better than where you were but it's still not great because that level of humidity, at the very least, is robbing your guitar of its best tone.

[rmoretti49]

Originally Posted by rmsstrider

Well, I removed the humidity packs from the case and it now sits at a steady 57% humidity for past 2 days instead of the 64% with the humidity pacs.

I spend a lot of time on a sailboat, so I understand the possible resistance you may be feeling towards a hard case. So, why not enclose your gig bag in a very large plastic bag? If you add a dessicant to the bag before doing so, you should be able to get the humidity down.

Also, you are probably aware that marine stores sell dessicants in large containers that are intended to be used in the boat's cabin. Some of these are reusable.