Many woodwind keys are accompanied by Cork bumpers and spacers. Some are merely to quiet the mechanism, and others are to establish and maintain certain adjustments, or regulations. Cork is a natural material, and unless you are using a type of cork that is infused with rubber, it will slowly compress over time. As a result, any regulations and adjustments will wander from their intended location and the corks will need to be replaced.

When preparing to re-cork a key, you first must remove the old cork. I scraped it off with a razor blade and then degreased with denatured alcohol since they were held on with shellac. One common practice is that you score the surface of the metal you are going to be adhering the cork to in order to give it a better surface. I'm sure it works, but I don't like putting scratches on an instrument intentionally! I guess habits of a player die hard...

The next step is to select your cork, and apply contact cement to one side of the cork and the part of the key you want to cork.

After it has dried, you apply a second coat, let it dry again, and then press the two glued sides together. They stick and it works like magic!

Next you take a utility razor blade (from the general hardware store or more than likely a dulled blade that had been sharp at one point in time) and do a rough cut of the cork.

Next you take a very sharp razor blade (the ones in hardware stores aren't NEARLY sharp enough, you have to order good blades) and trim the excess cork using the edge of the key as a guide. 

Not too bad considering it was the first key cork I'd ever cut.

We were told that many techs sand the edge of the cork at this time, but Lucas wants us to be able to get a nice finish without sanding. It just gives it a clean and crisp look that you can't achieve by sanding. I personally prefer the sanded aesthetic, but this is also very nice too and prefer it in certain circumstances. I know that I've come a long way since this cork!

The last step is that you must contour the bottom of the cork to the body of the instrument. To do this, you must sand it. You first put a clear static-cling tape on the body to protect it from any grit that has wandered to the back side of the paper.

Next you push down the key so the cork makes contact, and pull the sand paper. Don't pull it all the way out or you'll sand it unevenly. It's also highly recommended that you curl the paper in the shape of the tube so you don't end up with rounded edges from pulling the paper out against a curve.

Always pull the cork lengthways so that it won't come off. Here I'm actually pulling the cork side to side. That allows you to get the proper contour without damaging the bond of the glue.