Strings going sharp

Hi there. I just got a beautiful new Kanile'a tenor ukulele. I put new strings on about a week ago. I play a few songs, and some of the strings go sharp. Anyone have any ideas why?

New strings take time to settle and stretch out. Some take a few days, some a few weeks. So after playing some, the strings will need retuning during this period.

I've found that the only time strings go sharp is when humidity is high, the uke soaks it up, and strings go sharp. Never a problem, and I'd vastly prefer that to my uke drying out.

The various woods and string materials all expand and contract when subject to humidity and temperature changes. And strings are especially sensitive and tend to drift sharp when you bring it in a cooler room. If there's a temperature drop overnight, my treble strings are always a wee bit sharp. Put it in a hot car, it goes bananas! However, new strings need to stretch for a week or so—depending on how often you tune—but normally drift flat.

I'm assuming that some (but not all) of the open strings go sharp, and not that they are in tune when open and play sharp when fretted. If the assumption is right:

One possibility is the strings which go sharp are binding in their nut slots. You tune up to pitch, but because the string sticks in the slot there is extra tension between tuning peg and nut. When you play, the strings move in the nut and the tension equalises = higher tension on the playing side and thus the string goes a little sharp.

Were these a different kind of string from those they replaced? If so, they could be a fraction fatter.

You might fix this by putting graphite in the nut slots (pencil lead, just sharpen a pencil and get some pencil marks inside the slots). Graphite is a lubricant which won't hurt your strings. It wouldn't hurt to try this.

The other fix is to widen the nut slots slightly or, better, get someone experienced to do this for you, as you can make things bad pretty quickly if you don't know what you are doing!

Or it might just be the type of string. Aquila Nylguts do this to me - I tune, strum for 30 seconds or so, and then have to perform a final retune, and I know they are not sticking in the nut slots because i use a zero fret.

It is not so significant amount, but I have also noticed that when I tune the strings to pitch and then start strumming. Usually maybe half hour of my daily chords playing stuff and then check the tuning, it has gone sharper. My clip-on tuner has no percentage of sharpness shown, but I assume it is something like maybe 5 cents, so not much.

And it probably will go down by itself, not sure. My thoughts is that it could be some heat thing, can be also something to do with tuner windings, just beats me what it is. I have fluorocarbon strings.

I have found that the Living Waters strings I use on my tenors are more sensitive to changes in heat and humidity than other fluorocarbons like Worths or Martins.
Anyone else experience this? Or is it just my imagination?

Heat & Humidity = Expand
Cold & Dry = Contract

Thank you so much for all of this wonderful information. I will try the graphite in the slots.

Thank you. I will see how they do as they settle in.

I have a humidity gauge inside the case and have been keeping it at around 51%.

Ukecaster said:

I've found that the only time strings go sharp is when humidity is high, the uke soaks it up, and strings go sharp. Never a problem, and I'd vastly prefer that to my uke drying out.

Click to expand...

Temperature makes a difference, too. When I go a session at night, the strings are cold. I tune them, but I have to keep loosening them as they warm up.

UkuleleLadyT said:

I have a humidity gauge inside the case and have been keeping it at around 51%.

Click to expand...

I bought several hygrometers a few weeks ago, and I was surprised to see that the humidity inside my humidified cases was just about the same as in my un-humidified cases. I'll have to keep a close eye on them and see if I've been wasting my money on humidification.