This is a question that comes up on a regular basis on the forums and ukulele groups. People want to be artistic with their instruments and decorate them to show off their personal flair. Stickers, paint, ink, carving, etching and even wood burning are all methods people have asked about.
The ukulele is a small instrument. The instruments are designed to provide the optimal tones and sounds for the scale, size, shape, and tuning. On high end instruments, the wood is carefully balanced, shaped, sanded, and braced to give it the distinctive tones that tell us “That’s an ukulele!”
Anything you do to the instrument is going to affect that sound. How dramatic a change depends on the quality of the instrument. Your bright pink ukulele or the translucent green plastic uke you got for the beach are not going to be noticeably affected by putting a few stickers on them. That 75 year old Kamaka that your grandfather gave you will definitely be affected!
Where you place the stickers also makes a difference. The sound is predominantly determined by how the strings vibrate the soundboard, the top surface of the instrument’s body. Stickers on the neck or fret board are not likely to have any effect on the sound at all. You can find lots of great fret board sticker sets that can really spiff up an instrument and not do anything to change the sound. Making changes to the sides of the body will have less effect than the back, but both are preferable to putting a sticker on the soundboard itself.
Any time you change the thickness and weight of the instrument, whether it is through paint, stickers, different finishes or the removal of wood with burning, sanding, carving or even a laser, you will affect the sound. Permanent markers are going to have a smaller effect on the resonance than a heavy paint deposit from acrylic based paints. Anything that removes or damages the wood of the soundboard will naturally change the sounds of the instrument. On a laminate or painted ukulele it would not be too bad, it may not be enough for the average ear to notice, particularly on the lower quality instruments. Those changes would not be a good idea on a solid wood instrument.
Note that undoing your modifications may be impossible! Once you carve, burn, or etch the wood, you are never going to be able to put the wood back. The adhesive used on many stickers can be difficult to get off of wood surfaces. When removing stickers from a painted or glossy surface, some oil-based solvents might be used to get rid of the leftover adhesive, but it might also take off some of the paint or even pieces of wood.
So, my bottom line is:
- It is your instrument, you can do anything you like to it.
- On low end instruments you are not likely to make a noticeable difference to the sound quality.
- On a high-end instrument, or a vintage one, save the stickers for the case!