How to Replace the Cork in a Trombone Water Key

Obtain a replacement water key cork.

• If you're in a rush and don't have a replacement cork, you can make a temporary one out of a wine bottle cork.

Remove the old cork.

• Insert a sharp tool, such as one tine of a pair of tweezers or needle-nose forceps, between the cork and the metal edge.

• Pry up the cork using the metal edge for leverage.

• Repeat this at several points around the cork until the cork comes free.

If you have a replacement cork, skip to Step 10.

If you're using a wine bottle cork to make a replacement cork, place the cork on its side and measure 3 mm from the cork edge. Mark this point.

Using a serrated knife (such as a steak knife), cut the cork horizontally along your mark.

• Cutting corks can be tricky. Make sure to keep fingers out of your knife's way.

Using a ruler, measure the diameter of the water key slot you removed the cork from in Step 2.

• Measure from inside edge to inside edge.

Place the 3mm slice you cut from the wine cork flat on a surface.

Mark a point in the center.

Using a ruler, measure half the diameter from Step 5 above and below the center mark.

Rotate the ruler 90 degrees and repeat Step 7.

• Your cork slice should now have four marks equidistant from the center mark.

Draw a circle connecting the four marks around the center.

Using your knife, cut out this circle.

• It helps to slice edges off at angles, one at a time.

• This might take a few tries, so if you end up with a non-round circle cut out, repeat Steps 3-9 with the remaining wine cork.

Dry fit the new cork in the water key slot to make sure it is the right size.

• If your cork is too big, you'll need to cut it a little smaller.

• If your cork is a little uneven, don't worry. Its job is to seal the water hole, which is much smaller than the cork itself.

With a hot glue gun, put a drop of glue in the water key slot and place the new cork on top.

Press firmly on the cork for a few seconds.