How to modify your Fiberreeds
You can work on Fiberreed like you do it on a cane reed. Therefore you need sandpaper grain 500–1000 and for the rougher work grain 300–400. To make sure that you do not breath grinding swarf you should use abrasive paper for wet sanding and wet the reeds before you sand them or wear a mask.
Making your Fiberreed softer
If your Fiberreed doesn’t response well or seems to be too hard you have to make it thinner. Normally it is sufficient to work on the tip of the reed. The sound will get a bit brighter thereby. Take a piece of sanding paper and sand the tip of the reed on the first third of the cut carefully. After each sanding play your Fiberreed to find out what has changed. You continue this process until you get the desired result.
If the low register is hard to play you have to work on your Fiberreed with rougher sandpaper at the rear part of the cut. This is the last third of the cut where the reed achieves the full thickness and changes over into the shaft. It is necessary to remove more material to achieve noticeable result. It is essential here as well to play your Fiberreed after each sanding.
Making your Fiberreed harder
Take the fine sandpaper with grain 1000 and shorten the tip of the reed in a 90° degree angle (like filing nails).You may use a reed cutter as well. But the cutting edge will not be as smooth as before and should be reworked. You should not shorten more than 1 Millimeter (0,04 Inches) in general because the measures will change too much otherwise and will not harmonize anymore.
Making your Fiberreed shorter
Some mouthpieces are smaller than the standard measures. To make your Fiberreed smaller take it at the shaft and sway it upright on the edge on sandpaper with grain 500. Take care to hold the reed only at the shaft. You should never give pressure to the tip half of the reed because this would change the form of the reed very fast.
Cut your reed on both sides alternating until you reach the desired width. Finally you round the edges of the reed on the sides with fine sandpaper (grain 1000) at the part of the reed where the lips lay on it.
Adjust your Fiberreed to the tip of the mouthpiece
Take the fine sandpaper with grain 1000, work in a 90° angle (like filing nails) and bring the reed tip into the desired form.