I seldom use real cork anymore. Valentino synthetic cork lasts longer. I have used two Valentino sheet products for this. First I used the “tan sheet” on the left. But the correct product for tenon joints is the “cork sheet.”

The tan sheet is more rubbery, so it grabs or drags in the female part of the tenon. This is why I originally started using Teflon plumbers tape to make it so the joint is easy to assemble. I still use the tan sheet when I want the drag. For instance, some clarinets have a very short center tenon. Using the tan sheet on that kind of joint is helpful. The regular (spotty and lighter colored) cork sheet is slicker and don't drag. Tenon joints made with that material generally don't need any grease or Teflon tape.

Valentino tenon corks do not compress as easily as real cork does.
That is true unless the instrument gets way too hot. (As in, in the back seat of a car in the summer sun.)

Tenon joints using the new-style Valentino cork don't seem to need lubricating, but if you do want to make assembly easier, use Teflon plumbers tape according to the directions given below.

I am AGAINST using cork grease. Grease attracts dirt— lots of dirt.
It gets on clothes and ruins cases.


On wooden instruments, make sure that the metal ring on the female part of every tenon joint is tight. This is very important. If a tenon is not tight, putting outward pressure on a joint WILL cause it to crack!

Lubricating real cork joints:
I normally have used thick lip balm. I have tried using Teflon plumber's tape on real cork, but don't like the result. It can work fine on new cork. But if the cork is old, it compresses under the pressure of the successive layers of Teflon tape. The result is that you have to keep adding more tape and the joint always seems too loose.

[July2012] In the process of changing to Doctor's Products bore and key oil, Omar sent me some Doctor Slick. I like it and even use it on Valentino corks if they are too stiff. Of course it doesn't matter what you use on synthetic cork.
“Doctor Slick” Cork Grease from
Cork is wood too and petroleum based cork grease with eventually destroy the cell walls of the cork and they will rupture, collapse, and not rebound as they should to give an airtight seal. Cork cells are sealed cubes and the cell walls are elastic which allows the cells to be compressed and then rebound to their original shape and petroleum will shorten this capability.  Petroleum products will also dissolve the glue holding the cork to the tenon – called spinners which I am sure that you have seen in your work.

Emergency tenon cork repair:
It's the night of the concert and your tenon cork joint has just disintegrated! Now what?!
If there is a lot of unevenness in the remaining cork, remove it. Wrap the joint with dental tape, dental floss, or even thread. The waxed dental floss/tape works the best. If available, apply Teflon tape over the wrapping for a better seal.

For owners of my clarinets:

I have found it really challenging to find the happy medium for joints. I try to get them a bit on the tight side, because they will get looser. I try to get the joints tight enough that the clarinet can be safely used in marching band without it coming apart. But that level of tightness is often too tight for a beginning student with small hands.

If your Valentino tenon cork gets too loose:
There are two things you can do:
  • Quick Fix: See Emergency tenon cork repair below.
  • The Better Fix: Find the seam in the cork, and gently unpeel the cork from the joint. If it is one of my instruments, underneath you will usually find some thread wrapping. Put a layer of Gorilla Glue all over where the cork goes, covering the thread again with glue. Add more thread to the winding. (I usually add at least 30 inches of normal sewing thread.) Wipe off extra glue with a Q-tip. Then replace the Valentino cork that you took off before. The material is tough and stretchable, so can usually be stretched to cover the slightly larger winding. Hold the cork in place with a rubber band or two. Then keep an eye on this for 20 minutes or so, wiping away the glue that will bubble out. You can take off the rubber bands in a couple of hours.
Help! My Valentino cork tenon is too tight!
First, try just leaving the tight joint together overnight. This will compress the cork.

Wind a layer of Teflon tape on the cork and gently put the joint together. If you can't put it all the way together, just put it part of the way. Then leave the joint together for several hours to compress the cork. Keep doing this until you can put the joint all the way together. A somewhat tight joint will probably last a long time.

Second choice: Many have found that using cork grease or other similar lubricant will work until the synthetic cork finally compress enough.

Lubricating Valentino cork tendon joints:
This is for either old-style or new-style Valentino cork joints.
Use Teflon plumber's tape, sold at every hardware store, the thin kind that comes in the blue and white roll.

Teflon tape is so very slick! And it won't attract dirt. The problem is, it's so slick that it slips right off the joint when you put it together. But Teflon will stick to itself! The trick is to get your first layer to stay put, then adding more layers isn't a problem. So here's what I do:
  • Try putting one layer of Teflon on without glue. Carefully put the joint together with a slight turning motion. You may need to try this more than once, until the Teflon tape sticks or mashes into the synthetic cork. It often will take you 2-3 tries before you get the Teflon to stick where you want it. But if you give up on getting it to stick, you may use a tiny amount of  glue. Put on an extremely thin amount of Gorilla Glue,
    • wait a few seconds and wipe off any bubbles, letting the glue get tacky,
    • then put on the first layer of plumber's tape.
    • Wait about 20 minutes.
    • Put the joint together.
  • The thinner the Teflon coating the better. Only put on the layers needed to make a nice firm joint, putting on a layer or two at a time. Compress/Mash the Teflon layers together by twisting the joint together in the direction of the wrapping. 
Once you get the right amount of Teflon on the joint, it will work well for months with no further maintenance. From then on, just add another layer of tape when the joint gets too loose.

Note from Vintagemusic:
Phil recently reconditioned my clarinet using the new, light-coloured, Valentino cork on the tenon joints. The tenon cork is holding up very nicely. I have noticed, though, after six weeks of almost daily use, that the cork has lost some of the initial slipperyness, so I periodically apply a very thin layer of cork grease on it (not Phil's favorite, I know!). It still requires much less greasing then traditional cork.