Hey Dave! The cork on my water key is leaking and needs to be replaced. I’m not seeing anywhere to buy a pre-shaped cork online, only small discs in various diameters. Any advice other than getting a wine cork and carving it down?
Worn corks leak air until they leak water, so replacing a worn cork is important.
Your problem seems to be that you want a cork of a certain shape. Corks may be made of several different materials, from actual cork to synthetic materials of various types. They have three basic profiles: discs, tapered, and shaped (or “mushroom”) corks. Decide which profile you need to replace your current cork.
They also come in various diameters, which is usually the smallest diameter of the cork. You will need to measure the inside diameter of your water key, which presents a problem: how to do this without destroying the cork you depend upon to seal up your instrument? Don’t destroy it. Just order several sizes.
MOST water key corks for horn water keys are 8.5mm, 9.0mm, or 9.5mm in diameter. If you don’t know the diameter of your water key, I suggest you order one of each size. If you’re not sure which profile to order, I suggest you try the tapered corks, first.
Order your corks from a repair shop.
Almost EVERY repair shop can supply you with one or more type of water key cork in small quantities, which should be inexpensive enough to be affordable. You may have to call to order, because few repair shops bother putting water key corks for sale on their web sites.
To remove the old cork, stick a pin in the side of the cork. Gently heat the back of the pad cup that holds the cork. I use a butane grill lighter, eight to ten seconds. Open the water key and gently pull the cork out using the pin. It should just come right out.
Synthetic corks often have an adhesive backing. Natural corks need a tiny drop of cement to hold them in place. Press fit may work, but it’s best to have adhesive to secure your cork in place.
Dry fit the cork to be sure it fits the pad cup, then apply a tiny drop of adhesive if necessary, and push the cork into the pad cup. Put the small side into the pad cup. Test your water key to be sure the cork fits and that it’s not leaking.
Open the water key and make sure there is clearance and that the cork does not fall out. Done!
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Image credit: http://en.wikipedia.org/wiki/File:Wine_Corks.jpg