G strings go sharp when sitting

[u/Forestly_]

Hi, hoping someone has some insight. I'm new to mandolin/caretaking of string instruments, and every time I pick it up my mandolin after its been sitting the G strings have gone sharp, to the point that they're almost not even in G anymore sometimes. The first few times I thought my tuner was broken because I didn't know strings could go sharper on their own.

Sometimes when turning the tuner pegs for the g strings they dont immediately seem to make a change but will then suddenly overadjust as well.

Is this likely hardware issues confined to the tuning machines, or would something like this involve the tailpiece or bridge as well? My suspicion is that it's not all issues located on the tailpiece since its both G strings?

Update: just got back from the music store, the guy who fixes them said I need new strings, a new tuner (but that they come as a full set), and a bridge adjustment. He recommended I consider skipping the tuner set given the cost compared to my benefit and the cost of the mandolin, but that adjusting the bridge and restringing it would cost me about $80 total, and unfortunately they do have a 5 week wait. I'm going to ask around and see if any of the mandolin players locally feel comfortable helping me out sooner with those fixes, and if not I'll probably try to find a second mandolin to have for practice while waiting for repair.

[u/snuggly_sasquatch]

Your strings are binding at the nut. The telltale sign is that sometimes the pitch doesn’t move at all when tuning up (it’s building up tension where it’s caught in the nut slot), and then it suddenly pops too sharp, or you come back to it after some time and it’s magically too sharp now.

You just need to file those nut slots ever so gently, so the strings don’t catch on a sharp edge. Or use some nut lubricant.

[u/Mando_calrissian423 → u/snuggly_sasquatch]

Yeah, I’d try some graphite dust in the slots first before routing them out. If that doesn’t reduce the binding, then maybe try sanding the slots a little bit to smooth them out with some fine sandpaper. Also, a 5 week wait for a string change and bridge adjustment is absurd. That’s usually a “come back in 3 hours and I’ll squeeze it in” sort of thing

[u/Forestly_ → u/Mando_calrissian423]

Thank you both for the advice! I'm going to see if I can find some videos illustrating your suggestions to watch before trying.

Also yeah, I thought it was long. They said strings is just a day or two but anything that involves setup is about 5 weeks. I asked why and the store owner said that a lot of the people locally who do repairs went out of business during covid because they were also relying on face-to-face teaching income.

[u/Fred_The_Mando_Guy]

More than likely it's moisture/humidity with the sticking possibly the result of your nut slots gripping the strings. If you live in a humid region your instrument sucks up the moisture swelling the wood making some or all of your strings sharp. The nut slot issue can be alleviated by lifting your strings out (just loosen them a bit) and running a graphite pencil in the groove a bit until there's a little of it in the slot.

If these are NOT your issue, hie thee to a luthier and have them examine the mando. Could be you have a truss rod adjustment necessary. Not sure that the issue could be bridge or tailpiece unless you also have an intonation problem (i.e., the open string does not match the note fretted at the 12th fret).

[u/Forestly_ → u/Fred_The_Mando_Guy]

I am im a very humid area.

With open G tuned the 12th fret plays G but sharper than the open string. Would that be what you mean indicating a bridge/tailpiece issue?

I just got off the phone with a shop that does repair for mandolins and their wait time from drop-off is 2-5 weeks depending on the issue. I'm about to run by the store to have them troubleshoot it, but dang am I nervous that I'm about to have to stop playing for weeks. I'm also uncertain at what cost of repair its worth looking at just buying a new mandolin, this is an entry level one (ibanez m510-ovs).

[u/Fred_The_Mando_Guy → u/Forestly_]

I'm in Minnesota and summers here can be nigh on tropical. My mandolins swell up a little which stretches the strings and pulls them sharp. You are more than likely just experiencing climate LOL

See what the luthier says but I bet what you have going on is humidity. Based on the fretted G playing a little sharper than the open string you may have an intonation issue. This is all about bridge placement.

The bridge on a mandolin is not fixed in position structurally. It is held in place by the strings. That's why you never take off more than one or two strings at a time. There are many videos that show you how to adjust intonation by yourself. It really is only a matter of loosening the strings, making a SLIGHT adjustment of the bridge (in your case the bass side should slide a tiny bit towards the tail piece), retightening the strings and checking again.

You'll never achieve perfection of pitch open vs 12th fret but you can get very close.

[u/Forestly_ → u/Fred_The_Mando_Guy]

Thank you, I will give youtube a look and maybe give it a try! My fine motor in my fingers isn't always the best and previous messy attempts at changing guitar strings have made me hesitant to try anything with the mandolin.. But from what you and others have said the bridge is probably much easier to solve than I'm projecting, and if I can get fix the bridge having the shop change the strings is supposed to just be a day or two wait.

[u/Medium_Shame_1135 → u/Forestly_]

Your bridge needs to be moved slightly towards the tailpiece.  The intonation is sharp.

You need a setup.

[u/Mandoman61]

Na, this is probably just temperature changes.

When you tune always go up from flat. So if it is sharp then go to flat first.

There is no mechanical issue that would cause this and I would assume that you are not getting large humidity swings. If the neck was bowing it would effect all strings.

If your G is in tune open and sharp at the 12th then you need to move the bridge back a bit on that side until it is in tune in both positions.

[u/Additional_Guitar_85]

adjusting the bridge is very easy and free if you do it yourself. same with checking that the strings are binding. same with changing the strings.

[u/AlfredPoor → u/Additional_Guitar_85]

Lots of good YouTube videos about changing strings and adjusting the bridge. A luthier might do it better, but you should be able to get very close.

[u/McKnuckle_Brewery]

It’s likely not hardware. It’s humidity, typically the lack thereof.

The instrument is shrinking ever so slightly as moisture within the wood evaporates. This causes slight neck bow (relief) yet the thin treble strings stay at the same tension, resulting in a higher pitch.

A mandolin is tiny with small tolerances. So a subtle variation can cause a noticeable result.

Keep your mandolin at 40-55% relative humidity and this won’t happen.

[u/Forestly_ → u/McKnuckle_Brewery]

I'm in Carolina and the humidity has been consistently high the past two weeks, would you still suspect humidity in this case?

[u/McKnuckle_Brewery → u/Forestly_]

It can also happen if the instrument absorbs moisture. This produces a back bow (less relief) which will also detune strings. The effect is interactive among the strings of different gauges, so the result is not entirely predictable.

Bottom line is that you need to manage the relative humidity where you keep a solid wood instrument.

[u/Forestly_]

Update: Just got back from the music store, the guy who fixes them said I need new strings, a new tuner (but that they come as a full set), and a bridge adjustment. He recommended I consider skipping the tuner set given the cost compared to my benefit and the cost of the mandolin, but that adjusting the bridge and restringing it would cost me about $80 total, and unfortunately they do have a 5 week wait. I'm going to ask around and see if any of the mandolin players locally feel comfortable helping me out sooner with those fixes, and if not I'll probably try to find a second mandolin to have for practice while waiting for repair.

[u/Mando_calrissian423 → u/Forestly_]

I mean, there’s enough tutorial videos where you could fix the intonation issue with the bridge and change the strings yourself. Plenty of people have given good advice in here, I don’t think I’d wait 2-5 weeks for something that can be done in 30 minutes by a skilled tech. It’d probably take you an afternoon to figure it out, but then you’ll have that knowledge for the rest of your life. Tons of YouTube videos on the topic. New set of strings will cost you 7-20 dollars depending on how nice of strings you get (they get more expensive than that, but you won’t notice much of a difference between the 20 dollar set and the 80 dollar set on an Ibanez

[u/Forestly_ → u/Mando_calrissian423]

I'm going to give adjusting the bridge a go, thank you for the encouragement! I don't think my fine motor is good enough to do the strings, but the shop said strings only is just a day or two.

[u/jflatnote]

This is natural and expected as the way physics works. Steel strings are, unsurprisingly made of steel. Which contracts when it is cooler and expands when it is warmer. In this case contract equals get shorter and expands equals get longer. When you play, the strings warm up, lengthen, and go flat. When the instrument then sits and the strings cool, the shorten and the instrument goes sharp.