The belt works at full efficiency: Even little pressure on the belt will remove a lot of material. The needles are sharp and straight. They don't break off.
Phase 2:
The sharp needle ends have become dull. The pressure on the belt was increased to try to compensate for the decrease of efficiency of the slowly
dulling needles. This caused the needles to be bent backwards and some of the needles fell out. The belt is used up and the needles must be
resharpened which will straighten them out. For resharpening, turn the belt around and run the needles against concrete or sand paper with 60 grit.
After 3-4 times resharpening, the belt is used up and needs to be replaced.
Phase 3:
If the belt is not resharpened or replaced as mentioned in phase 2 and the pressure on the belt is increased, the condition as shown will appear. Most
needles have fallen out and the remaining ones are sharply bent to the back.
Explanation:
A traditional sanding disc is used up in a constant curve and you see how much is has been used and how much life is left in it. Opposite to this is phase 1
in which the belt works with no usage visible for a long time. The change to phase 2 and quickly to phase 3 comes sudden and is considered normal.
Our Tip:
If efficiency of the belt drops, look at the belt and if phase 2 starts change the belt. Increasing the pressure as well as incorrect use are reducing the life
of the belt in phase 1. Again we want to point out that the life of phase 1 can be extended with resharpening as mentioned in phase 2.