How to Replace the Cork in a Trombone Water Key

Obtain a replacement water key 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.

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

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.

Draw a circle connecting the four marks around the center.

Using your knife, cut out this circle.

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.