As a new reed takes on moisture, the wood swells and the cells shift. Any change in the original shape of the reed due to swelling is considered warpage. The most typical problem are of a warped reed is the bottom flat side, which tends to bow (or sag) down the center line and pull up towards the edges. The affect makes it difficult for the reed to seal with the flat side of the mouthpiece.
During the breaking-in process, practically every reed will warp on the flat side, and may need to be corrected several times before you play the reed for the first time. Once a reed is well broken-in, it will likely warp very little during the remainder of its career.
Three methods of testing for warping are:
- Rocking method
- Flat file method
- Paper method
Place a reed that is dry or at least finger (well wiped off) on a flat piece of glass (plate glass, like a coffee table, or one of those handy glass plaques used for reed adjusting). With a finger on either side of the shoulders, apply pressure back and forth. Now move your fingers down the length of the bark area, repeating the same back and forth pressure (see pic below). As you do this, look to see if the reed is also rocking back and forth on the glass. Most reeds will have a tiny bit of motion, but a warped reed will have a significant rock from one side to the other. This is a good method for gauging severity of warpage.
Flat File Method:
A few swipes along a flat file will polish the warped areas of the reed while leaving low spots dull. Hold your reed up to a light source and notice how the reed reflects light. If the center is shiny and the edges are dull, the reed is warped. A non-warped reed will be glossy across the entire flat side.
Note that the area under the vamp will almost always be dull at the edges. This is okay. You are only looking for warping in the area that meets the flat table of the mouthpiece.
Identical to the flat file method, only use a flat sheet of paper on a glass surface. You will have to apply more pressure to the reed to polish high-spots.
Fixing a warped reed:
This is the most tried and true method for correcting a warped reed. Simply place a piece of 400-600 grit Wet-Dry sandpaper on a VERY flat surface (plate glass is my favorite). Place the flat side of the reed on the sandpaper and three fingers on the reed; one finger on the center of the vamp staying away from the tip, one finger at the shoulders, and one in the center of the bark area. Now with light and even pressure, glide the reed across the sandpaper in a circular or ovular pattern (never back and forth!) about five times. Now recheck for warping to see if you have removed enough wood.
With the sandpaper method, there is always the risk of taking off too much wood, so err on not going quite far enough. Play the reed after the first correction, and you will probably find no need to continue sanding. If a reed is so warped that correcting greatly thins the reed, you may have to clip the tip to maintain proper resistance. Too much sanding and clipping may ultimately be the demise of the reed.
If your reeds routinely require excessive sanding, check the sections on basic care to reevaluate your break-in and storage methods. You may also wish to check for your reed’s profile in the research area for more specific information on caring for your reed style.
Reed-Geek tool method:
If you have a Reed-Geek “Universal” tool, you can quickly make slight adjustments on the flat side of your reeds. This method is great for correcting slight warping issues while on the go, since the tool is portable… and carrying sandpaper and glass is quite cumbersome!
Hold your reed, flat side up, in your non-dominant hand, and the reed tool with your dominant hand. Grip the reed at the center of the vamp, with the heel facing away from you. Now, with even even EVEN pressure, swipe one of the long edges of the tool along the reed, back and forth, until you remove some wood. Now rotate the reed so that the tip faces away from you, and repeat your swipes along the under-the-vamp area. CAUTION: Do not swipe the tool all the way up to the tip of the reed! There is no need to take wood off of this area and the risk of cracking the tip in immense with the “Universal” tool!
Believe it or not, the flat file does not take an adequate amount of wood off the reed to be useful in correcting a warped reed. However, it is ideal for taking off the little bump that forms in the spot where the reed is pressed into the window of the mouthpiece (see basic care).