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I've got an Alvarez that has totally dried out. There's a massive hump at the 14th fret and with the neck straightened flat a straightedge sits about an 1/8" above the bridge.

I've had it sitting in its case for a couple days with a sound hole humidifier, there's been a bit of improvement but not a lot. I saw a pdf online put out by Taylor, they suggested 4 days would be enough to re-humidify a severely dried out instrument. Any thoughts?

I just worked on two very dry Martins. One had a totally flat top, the other was actually concave and had a crack starting. I put two of my sponge/baggie humidifiers in them (one inside, one in the case) and told both owners to come back in 3 to 4 weeks.

The one with the flat top I shimmed the saddle by 40 thousands since the guy has a gig this weekend - I can take the shim out or reduce it as the top comes back up. The other one would require at least 60 thousands of additional saddle height to get it playable again - thats a lot. The sad part is that it is a relatively new D-18.

Four days ain't enough. I remember an old Taylor vid where Bob shows putting a dry guitar in a plastic garbage bag with a bunch of sponges. I also remember his comment that he consider a dehydrated guitar "abused" and not under warranty.

This is how I do them.A severely dehydrated guitar can take 3 weeks in a bag like this to re humidify to a proper level.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Also, I recommend against re humidifying in the case. The case will be as dry as the guitar and will be sucking moisture too so you are trying to re hydrate both right now....

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

This is my standard humidifier - cheap and easy and each guitar has one in its case. I also have a small humidifier in my music room, it pumps a gallon of water into the air each day. The RH in my house during the winter typically ranges from 20 to 35 percent even tho its 80 percent outside (and the ground is covered with snow).

To rehumidify a guitar I typically put one or two of the baggie/sponges inside the guitar (down in the lower bout). Sometimes I'll put a butter container in the sound hole to keep the moisture inside, mostly not tho. I'll put another baggie/sponge in the head area of the case and give the guitar back to the owner (or put it away in the basement). Dampen the sponges weekly, the guitar can be played but the action will be wonky.

After a few weeks I compare the top and neck angle to what I measured originally. I know there is a good chance it won't come all the way up. When it seems to be stable I'll do the setup

Ps - one of the guitar in my original post was a fairly nice D18. I took it back to the store that I do work for, the owner came it to pick it up. He asked if the store or I had put the "scratch" in the top. I told him that was a crack and it was only going to get worse

I hydrate guitars often for dried out crack repairs. The idea I have discovered is that the more surface area of moisture in the guitar the quicker it will hydrate. I started out using a cup of water inside the body, then closed it up in a plastic garbage bag. It took 5-7 days for the woods to swell enough for cracks to close. I recently started using a damp wash cloth laid out on wax paper inside the body, closed up in a garbage bag. The wash cloth has significantly more surface area than a cup of water (or sponge, especially sponge in a bag). Using a wash cloth, the guitar was well hydrated within a day or two.

We've got half a dozen bagged and tagged right now. For slightly dried out guitars as little as a day can get you where you wish to go. For the worst cases we might do a week but no longer being concerned about the glue joints. Typically we're keeping a guitar bagged for several days.

It's important to speak in terms of data when speaking of humidifying guitars. Our method for bagging in a large garbage bag (clear so we don't get them confused) with a car wash type sponge and maybe two cups of water in the bottom of the bag produces a typical RH inside the bag of around 75%. We've tested this with calibrated hygrometers. Be sure to have some of the sponge out of the water puddle in the bottom of the bag. The sponge is supposed to act as a wick meaning it needs to have air exposure too and not just be totally wet.

Bagging is not a remedy for a hump at the body joint and our bags only contain the body not the neck.

We are just as frequently as we are bagging to blow a guitar back up in it's specs we are taking it out of the bag and letting it stabilize at 45% RH for a day or more to get a crack to loosen up enough that with a pumping action you can get glue in the crack. Sometimes the cracks close too much and we have to wait a day or so with it out of the bag.

Commercial grade guitar and case humidifiers are not powerful enough to bring a dried out guitar back in a reasonable amount of time. What's reasonable, not weeks, no one wants to wait weeks and we don't have a sign at our shop encouraging dead guitar storage either.

We don't employ any form of interior humidification when bringing them back, never had needed that with how we do it.

We have a client who tried multiple interior humidifiers on his D-18 and his braces came loose, nearly all of them..... No warranty coverage either this was abuse. You could see water stains on the back where his overly wet sponges in home made containers let out too much moisture too quickly.

WOW! I never put that much moisture in the bag!I prefer to re hydrate gently as I feel it stresses the bracing less as the wood expands back slowly to it's original position, the quicker it moves the harder on the glue joints. I use a small tupperware containers with 1/4" holes in the sides and lid with a dish sponge cut into one inch cubes inside. These are made quite damp, to the point of dripping. One goes through the soundhole into the body and the other lies inside the bag.Average dryed out guitar takes about 1 week but bad cases have taken 3 or so.... This will also depend of the guitar and what it is made of to some extent. For example it will take less humidification to close a crack in spruce than it will a Brazilian rosewood due to differences in the wood itself and how it interacts with RH.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Hey Bri my facebook friend:)

Try this we've never had anything come loose as a result of how we humidify guitars.

Guitars can live in very high humidity for some time before they start to fall apart. We won't bag for over a week but being able to bag, tag, restore a dome and get an instrument back in the hands of a performing professional musician in two days at times can be desirable for all.

We're not the only ones doing this either, other shops do what we do and some even have a chamber that's sealed. I don't like the chamber idea for us because Dave would lock me in there on the days that I have bad gas.....

Just remember to let the thing stabilize outside of the bag/chamber/what ever to 45ish% before working on it since it will move back somewhat. A day out of the bag before working on it is standard fare at our place now.

Thanks guys, Hesh you mention re-hydration is not a solution for a hump at the body. I have no idea if this guitars hump was produced by being dried out, but I think its a pretty safe assumption that the drying out was at least part of the cause as he regularly played his guitar, then moved his practice space to his basement office with a woodstove burning in it. He came to his weekly guitar lesson and suddenly couldn't play any more. His teacher (not me) tried dealing with it by slacking the truss rod off all the way but it didn't solve anything as the strings all fret out now at the 14th fret regardless of the amount of relief. Luckily there are no cracks, loose braces, or other glue failures that I can see. But if re-hydration isn't the solution for my issue, what is? The saddle does seem low to me, but as it is to clear the 14th fret I'd need a really high saddle.

Wait, I think I may have been thinking about the 14th fret hump being the problem in a wrong way. As the guitar comes back to an appropriate humidity, it should restore the dome which would raise the bridge back up to the proper height in relation to the fret board. The hump and fall away will still be there, but no longer an issue in regards to playability. Is this a correct line of thinking?

Hey Connor, I hope that you are doing great.

Yeah you're getting there. Rehumidification will help restore the dome on the top raising the action a tad now you have to deal with the other end.

Necks often go into back bow when a guitar is dried out. After the instrument has been rehumidified step one is to adjust the truss rod, pretty straight on the treble side unless the bass side is straighter and the limiting factor. I adjust the rod, cut the nut slots and then deal with action at the 12th.

Adjusting the rod for a pretty straight neck often will take any body hump out of play. The body hump was likely always there and not a result of being dry but a collapsed dome and back bowed neck made the hump more obvious, pronounced and deadly to choking out the strings.

Feel the fret ends on the sides of the neck. Are they proud, sprouting out a bit and sharp? If so that's yet another tell tale of a dried out guitar AND neck. The neck wood shrinks, usually somewhat permanently and the metal frets don't so they feel sharp. I have special files that will skate on finish but bite into the metal fret ends that I use to take the ends back and then I spend a few minutes rounding them nicely again for clients.

Try adjusting the truss rod and let us know what you found? Was the neck in slight back bow or if the neck has too much relief it can also exploit any body hump and this has nothing to do with being dry. Folks rarely adjust truss rods so that necks are flat enough and this makes other limitations such as ski ramps on the extensions and body humps more problematic.

Above all have the guitar stabilized in 40 - 50 RH for a few days before making any final adjustments and be ready to lecture the client and send them home with some knowledge and maybe a guitar case humidifier if your climate benefits from these devices.

I've been ramping up the humidity over the last several days, I started at the beginning of last week with a simple sound hole humidifier in the case, then added a wet rag inside sitting on wax paper (making sure there was no water sitting anywhere), finally I switched over to a garbage bag on Saturday and added a yogurt container with a wet rag inside poking out of the water. Things are starting to get better, if I play very gently I can get away with no buzz, but its still pretty bad.

I've got the truss cranked pretty tight, but still have .007" of relief. The fret ends aren't sharp. The action at the 12th fret is super low, a hair more than 1/32" and the saddle seems to be sitting super low in the bridge slot, protruding about 3/32". Checking the neck angle, my straightedge is now sitting a little less than 1/32" above the bridge.

To my eye, the set up in wetter times was probably pretty low, but okay, and this cold snap coupled with a new home in a room powered by wood heat sent it over the deep end.

I think I'll give it a few more days, but that saddle seems really low

On a related note, this is really only my second winter doing guitar work so the dry winter thing hasn't really ever been on my radar. Needless to say I've got a humidifier and humidity meter now.

Conor, just to summarize, there are a number of different symptoms of a dry guitar - you may have one or more. Most guitars have some dome in the top - if you lay a straight edge across the top behind the bridge there should be a gap of maybe 1/8 inch or a little more. When the wood drys it shrinks, the top sinks and may be flat or even concave.

That means that the action goes down - the guitar may get buzzy, particularly up the neck.

The apparent neck angle changes and the neck seems to be over set. In reality the angle hasn't changed but because the bridge is now lower than it was before it appears to change. There are very few other failures that cause a neck to appea over set (straightedge above the top of the bridge)

As the top shrinks it often cracks - usually along the center seam but can be else where.

The finish can appear kind of wavy - it looks like the grain lines in the wood are highlighted

The fretboard shrinks but the frets don't so the ends stick out and get sharp.

Extreme cases the back or sides might crack.

This is a very oversimplified picture but it kind of shows what is going on at the neck/body joint. Because the neck gets real stiff at the heel most of the bowing under tension (relief) is from the nut to the heel. At the body joint the f/b follows the geometry of the upper bout - it might be flat, it might be glued down "falling away" or it might be bent up ("ski jump"). Most of the time flat or fall away is OK since all that means it the action is getting higher above the 14th fret and very acoustic players go there. The body joint fret (14) is usually the big trouble maker - attention to that fret plus minimum relief usually make the guitar acceptable. Again, look at the little picture - with minimum relief the hump at the joint mostly goes away.



My suggestion is to force feed some humidity and watch the top until it seems to stabilize back to some sort of dome. If you go thru a lot of work setting it up before it is stable you are just going to have to do it again since the action will continue to go up. I think a reasonable approach is to shim the saddle, then remove shims as it returns to normal. Ideally, if the action was perfect last summer you will come back to the same setting.

I think you can do a lot to educate your customers. I buy kitchen sponges by the dozens and I put one in every guitar case that comes into my shop unless there is already something there.