De-tuning is the dulling of the sharpened edge to reduce the bite of the edge and ease the transition of the edges at the tips and tails with a diamond, aluminum oxide, ceramic or natural stone.
Traditionally, this has been the typical method to finish a ski or snowboard edge after sharpening and polishing. With modern skis, this is now considered unnecessary by many, as it is desirable to utilize the whole sharp edge for carving turns. Slight increases of base bevel geometry, called feathering, at the tips and tails can be used instead to control the transitions into and out of a turn. This is specially true for carving skis to maximize the performance built into the skis.
De-tuning still may be necessary or desired if the tips and tails catch or to make initiating and ending turns easier, especially for novices, extreme or off-piste skiing, park tricks or snowboarding. Rockered skis can also benefit from either de-tuning or increasing the base bevels at tips and tails to avoid catching them when riding on hard-pack or icy conditions.
If you wish to de-tune, start from tip or tail to contact point (where the tip shovel or tail end first contacts the snow surface when on edge), initially, and increase the length only after skiing or boarding to test. It is far easier and fast to de-tune than sharpen and a little will go a long way. This can be done very easily and quickly, a little at a time between or even in the middle of a run as you feel the skis or snowboard and can make minute adjustments relative to current feedback, until you are satisfied. This extent can then be applied in the shop the next time you sharpen, after you ‘know’ what you need.