One of the most common but also simple issues are key bushing felts. These are the felt pieces which line the holes in your keys, keeping them firm against pins.

When they come off they causes the keys to wiggle, shake, stick and generally move very awkwardly.

Instructions:

Glass Jar: We included this glass jar because glue pots generally suck. They're messy, you heat up tons of glue, they cost a ton and for most people looking to work on their own instruments they are not worth getting. This glass jar, containing a small but useful portion of hide glue can be heated up easily in an improvised double burner. (Take a shallow pan. Fill with water, place the jar in the water.) It has a tight lid for storage and can be recycled or reused indefinitely.

Heating the Glue: Soak the glue overnight. Cook the glue very slowly, under very low heat for about 30 minutes. (around 100 degrees so it shouldn't hurt to touch the surrounding water) Then turn the heat up slightly to bring the glue to around 150 degrees (Fahrenheit) and use the brushes to apply evenly. Keep the jar covered as much as possible to avoid evaporation. 

As with any heated glue, there is reduced window of working time, but the great thing about hide glue is that it can be re-heated many times to re-set and repair. There is, of course, an odor with natural hide glue so we recommend using some sort of ventilation.

Removing Key Bushings: There are few techniques for this. Our favorite DIY style one is cutting up bits of sponge to soak the existing key bushings overnight. The using a heatgun and some sort of scraper to remove the old key bushings. Once they're out, thoroughly clean the holes and let them dry out fully if they remain a bit moist.

Applying New Key Bushings: There are several styles of key bushing slots and thus several styles of felting techniques. Simply try to match your new work to the existing felting as closely as possible. Use the brushes to evenly apply glue to the felt, then place the spring clamps in position and leave to set for 12-24 hours. It can help to leave a good bit extra on each side to adjust and re-adjust the felt position. 

There are a number of good videos on youtube detailing this process. We highly recommend checking out a few to get a feel for the process. The spring clamps especially make for simple quality repairs that resist most common errors. It's really very simple so don't be intimidated. 

Let us know if you have any questions. We're here to help!