Humidification Situation

[jaycat]

Hey all, hoping someone can shed some light. . . .

I have an old Gibson A mando w/two frets that intonate badly. It was looked at by a luthier who managed to fix them, but a week later they were going sharp again.

Took it back & he asked me had I been humdifying the mando? Uh, no. OK, so he sold me a humidifier, I stuck it in the case, and here it is 5 weeks later and little or no improvement.

He also had told me 'everything'll be OK by June anyway (when we here in New England have stopped heating our houses)', and further, when summer comes, I should remove the humidifier from the mando case or some other dire things would happen

So I'm somewhat confused. And here's another question -- is it better to leave the mando in the case with the humidifier if it's a warm rainy day anyway? Would it be better to leave the case open on a day like that?

Thanks all!

[Capt. E]

When not playing, it is almost always a good idea to keep your instrument in its case. That slows down the changes in humidity, temperature etc. In an ideal world, you would keep the instrument in an enviornment of about 40-45% relative humidity (probably good for us people as well). Below 30% for extended periods can cause damage. High humidity isn't as much of a danger, though high heat is. (Don't EVER leave your instrument in a hot car)
An instrument without a truss rod is more sensitive to humidity and temperature changes, though the shorter, robust neck of the Gibsons are pretty resistant. I find my Martin A going sharp or flat if there has been a strong humidity change since I last tuned and played: perhaps as much as a 1/4 step. Also, the playability can be affected with subtle changes in the line of the fretboard such that 7th to 10th fret may sound a bit "off". My guess is the intonation problem you have is around the 7th to 10th on your Gibson.
That's about the extent of my wisdom on this matter. I'll leave it to others to add to it or correct any misconceptions I might have.

[jaycat]

Good guess. 8th fret on the E string and 9th fret on the D string.

[Keith Erickson]

I can't tell you enough how important it is to humidify your instrument. I live in a climate where we are at around 8% percent humidity. I am a fanatic about that humidifer.

[Goodin]

Hi JayCat - It is likely that your intonation problems are not from humidity but from the fret slots being cut in the wrong place at the factory. These old Gibson A's are notorious for having quality control issues with fretting. I have had two Gibson A's from 1925 that both had intonation problems on only a few frets. The only solution is to replace the fretboard (or possibly pull the bad frets, fill the fret slot, and recut the fret slot in the correct location). Consider having your luthier measure each fret distance from the nut and compare the measurements to the Gibson scale length specs.

[jaycat]

Thanks for the input everyone. Goodin: on the 8th fret of the E string, the inner string actually is much closer to a true C than the outer, which sounds a definite C#. Does that still sound like a fret issue to you -- have you had a similar experience?

thx, jc

[JGWoods]

I am just north of you in Chelmsford MA. I have a 1917 Gibson A4 with a 1 piece bridge. For a few years- before I got a room humidifier for the room where I store all my instruments- the A4 action would sink down in the winter as it dried out. By mid-winter is was not playable with buzzes and worse. It didn't matter if I kept it in the case or not- all that does is slow down the changes by a day or so.
I could fix it by putting 3 chunks of wetted (wrung out) sponge in baggies pierced with a few holes- one inside the body on a string, one at the headstock and one down by the tailblock, close the case, wait 3 days and the top would rise back up to normal and it was fine again.
Now I keep it in the humidified room at about 45% rh in Winter and never have a problem. If I run the humidifier dry it goes flat as the top almost immediately begins to dry out and sink down. If I fill the humidifier and wait 6-5 hours I find th tuning has gone back to pitch as the top rose. It's like I can use the tuning as my humidity meter.
If I go to play and the tuning is quite flat I check the humidifier, fill it, and if I retune for a session I wind up detuning a bit when I am done so the top tension doesn't go too high as it re-humidifies. Does that make sense?
Anyway- it breathes, up and down all the time with the weather and seasons. I think that is one of the key means by which instruments play in over the years and get stronger with better tone. If kept at an exact same humidity they never bloom. That's my theory and I'm sticking to it.

[JeffD]

These old Gibson A's are notorious for having quality control issues with fretting. .

I have never heard this. I am not saying its not true, I have just never heard this at all.

A's without a truss rod are going to be more susceptible to humidity changes as was mentioned, and so many As were made I am sure many of them have not been taken care of and over the years would develop all kinds of problems the solution to which might only be a new fretboard.

But I have not heard that they were notorious for incorrect fret slots, or any other quality control issue actually.

[jaycat]

I am just north of you in Chelmsford MA. I have a 1917 Gibson A4 with a 1 piece bridge. . . . .

Hey Chelmsford, thanks for the good info. But it doesn't sound as if you were only having trouble with two strings at two discrete frets, which is what is puzzling me?

[Goodin]

Thanks for the input everyone. Goodin: on the 8th fret of the E string, the inner string actually is much closer to a true C than the outer, which sounds a definite C#. Does that still sound like a fret issue to you -- have you had a similar experience?

thx, jc

Are both E strings the same gauge and manufacturer? How old are the strings? You may want to simply replace the strings. I don't think this would be a fret issue. The nut or bridge slots may be too narrow on one of the E strings which is choking it and not allowing it to vibrate as it should, therefore throwing off the intonation. What gauge strings are you using? If they are heavy gauge you may want to replace with medium gauge strings, or if medium, try light gauge. You may want to make a new thread in the Builders section of the Forum to get better advice from the luthiers there.

[Goodin]

I have never heard this. I am not saying its not true, I have just never heard this at all.

A's without a truss rod are going to be more susceptible to humidity changes as was mentioned, and so many As were made I am sure many of them have not been taken care of and over the years would develop all kinds of problems the solution to which might only be a new fretboard.

But I have not heard that they were notorious for incorrect fret slots, or any other quality control issue actually.

I have owned two 20's Gibson mandolins with fret slots cut in the wrong place. This is easily confirmed with a 64ths/inch graduated ruler (and a magnifying glass!) by measuring the distance from the nut to the frets in question. So this is from my experience and also I have heard that the fretboard work on the cheaper Gibson A models was outsourced.

[JeffD]

I have owned two 20's Gibson mandolins with fret slots cut in the wrong place. This is easily confirmed with a 64ths/inch graduated ruler (and a magnifying glass!) by measuring the distance from the nut to the frets in question. So this is from my experience and also I have heard that the fretboard work on the cheaper Gibson A models was outsourced.

Certainly I can't argue with your exprience.

Look I am not saying you are wrong. This is just the first I have heard of there being more of these kinds of problems with the old Gibson A models than would be expected.

[BradKlein]

There are certainly LOTS of fine vintage Gibson's with inaccurate fretboards from various eras. You can easily see it by placing a modern slotted board or a slice of one, if you happen to have trimmed one of the right scale to width, alongside the vintage board. Or use a ruler or scale ruler etc. It's not at all subtle on MANY instruments. (and you have to remember how very very many mandolins Gibson turned out in the teens and twenties)

Then you have to decide: live with it? replace the board? fill slots and re-cut?

[jaycat]

There are certainly LOTS of fine vintage Gibson's with inaccurate fretboards from various eras.

I'm still trying to understand whether this could cause only one of the pair of E strings to intonate incorrectly at one fret?

[250sc]

The fact that it was fixed and the symptom got worse again kind of rules out fret slots to me.

[JGWoods]

Being as it is the 8th, 9th frets that pretty much leaves out the nut. Is there significant fret wear at those locations? I also have a 1942 Martin A and a 1935 Maurer A and a fret dressing was necessary to keep the pairs playing the same. Much as I love the old stuff I am thinking I would wreck half their value and refret with modern banjo wire just to have the better playability.

Also I would change the strings if you haven't already done so. I can't give a rational explanation as to why that might fix the problem but I have seen it happen- problems disappear when the new strings go on.

[jaycat]

Had a set-up w/new J74s in early March. Here's what got done:
Loose brace reglued
Fingerboard cleaned and waxed
Frets polished
Machines lubricated
Restrung
Bridge lowered/fit to top
Bridge position adjusted

[Bob Clark]

Here's my humidity story and my solution to the problem. In addition to mandolin, I also play piano. In fact, I have played piano a whole lot longer than mandolin. If you think MAS gets expensive, you ought to see what happens when you get a good case of PAS!

I had a below-the-soundboard humidifier on a reasonably expensive grand piano. The unit malfunctioned and I ended up with a forest of mold on the bottom of the soundboard. That resulted in an acute case of PAS and a new grand. I did not want to risk that problem again, so I looked around at other solutions to the humidification problem. I decided that for me, a free standing (not part of a heating system) built-in steam humidifier would be the best way to go. I put in a Scuttle steam humidifier. It is mounted below the floor, to the floor joists. It has two floor registers placed a few feet apart. When the humidistat calls for moisture, it draws air in one register, the air flows over a water bath containing a heating element that boils the water, adding steam into the air. The air exits through the other register into the house. The unit has its own water supply line.

This system holds whatever humidity I set it for, to within about 1% of variation. I keep it set at 42% during the heating season and it holds that very accurately. It has a flushing unit that cleans out the bath twice per day. I clean it thoroughly at the end of every heating season, when I shut it off for the summer.

It really does hold my whole house to the set humidity. I use a digital humidistat to make sure it is working properly. With this in operation, I don't worry about my mandolin or my piano. I know that they are well humidified.

These units are expensive, but when you consider what some of us have wrapped up in our multiple instruments, I think it's worth the price. Just my solution to the problem. It has worked well for me.

Best wishes, Bob

[JeffD]

It is mounted below the floor, to the floor joists. It has two floor registers placed a few feet apart. When the humidistat calls for moisture, it draws air in one register, the air flows over a water bath containing a heating element that boils the water, adding steam into the air. The air exits through the other register into the house. The unit has its own water supply line.

That seems the right way to do it. Did you put it in yourself? You probably had to put in the water supply line, was that a lot of work?

[michaelpthompson]

I've never done one of these humidifiers, but I've put in water supply lines for an automatic icemaker, which should be comparable. It's cake, presuming you've got access to a cold water supply pipe somewhere near where you want the unit. An icemaker installation kit comes with a self-piercing valve and either copper or plastic supply line. I think the copper lasts longer myself, but you have to be a little more careful about kinks. Bolt the valve onto the cold water pipe and turn the valve tight until it pierces through the pipe. Attach your water line and hook it up to the humidifier. Open the valve and voila, you've got water. It's usually only a quarter inch supply line, but that should be plenty for a humidifier. Used the same setup for swamp coolers and it works a treat.

[Bob Clark]

Hi Jeff,

Yes, I installed it myself. I bought the unit over the internet and, as Michael mentioned, hooking up the water line was simple. It did involve a self-piercing valve as Michael said, and I used a quarter inch copper line (Michael, you have it exactly right). I did add a small filter in the water line as I am on a well and sometimes a little sand or precipitate might make it through. That was no big deal though.

The wiring was easy too. It came wired with two electrical plugs (one for the humidifier and one for the self-flushing timer). Rather than hard-wire it, I simply wired up a duplex receptical (typical outlet) next to the unit and plugged them both in. I put them on a dedicated breaker, but I don't think they draw all that much current anyway.

The part I scratched my head over was how to support it under the floor joists, as it does not come with a mounting bracket. Again, a simple solution worked fine. I just bolted angle iron onto the sides of the unit and into the joists. It's rock solid.

The duct work was also easy. I just formed sheet metal ducts and put them up. If you decide to do this, let me know if you would like pictures of how I did it. I'll shoot some and email them to you. It has worked out well for me. Other folks might have other solutions though. I am sure there are many ways to solve this problem.

Bob

[Bob Clark]

Michael,

I'm curious. What's a swamp cooler? Sounds like something I might like!

Bob

[dcoventry]

Google Swamp Cooler. All will be revealed. It can be as simples as a skin of water hung in front of a fan. They are often seen in the AZ. area and other desert areas.

[michaelpthompson]

Michael, I'm curious. What's a swamp cooler? Sounds like something I might like!

I probably should have added it's official name, evaporative cooler. We call them swamp coolers 'round here. It's basically a big box with fiber matting across vented sides. There's a tank at the bottom that fills with water from the inlet line, it has a floating shutoff valve to keep the water level consistent. Then an electric pump pumps the water up to the top where it trickles through the fiber pads. A fan sucks air through the wet fiber and blows it into the house. It's an excellent cooling method in dry climates, such as Colorado, where I live. (Not actually helpful for cooling a swamp.) Not as expensive as refrigeration, simpler to install and maintain, and adds moisture to the air at the same time.

[jaycat]

Hey wait a minute! I'm not sure when this thread turned into an episode of This Old House :-) . . . but, getting back to my lowly mandolin case, does anyone have any thoughts on removing the humidifier during the summer months?

PS: the problematic C note is sounding better this morning. So I'm thinking my luthier maybe knew what he was talking about after all.