A correctly tuned side edge will raise a hanging burr on the newly sharpened junction of the base & side angles. You often can’t see this burr but you can feel it if you pull your fingers across your base edge towards your side edge. This burr often mistakenly makes the ski edge feel sharp to the uninitiated. The edge may feel sharp to a thumb rubbed across it & it may remove a sliver of fingernail drawn across it, however, if you slide a piece of fiberleen or tissue down a burred edge it will snag on the ragged edge. Unless the burr is removed so the edge is still sharp but also smooth & snag free the ski’s performance will be totally erratic as the burr sticks straight down into the snow as a continuation of your side edge and makes your skis very grabby and unpredictable. It will cause the skis to be difficult to roll on & off edge smoothly & make them feel twitchy. This is one step which is often critically omitted with a shop tune.
There are two methods for removing the hanging burr:
There are two methods for removing the hanging burr:
Basic Method
Use a hard gummi stone held flat on the base of the ski - do not try to angle the gummi to the base edge angle. Note that a HARD grade gummi must be used as a soft or medium grade gummi will 'bleed' over the junction of the base/side edge & actually blunt it. A hard grade gummi, when held flat on the base of the ski, has just enough 'give' in it to 'mould' on to the base edge angle to remove the hanging burr but is not so soft as to bleed any further over to cause harm. Good results are easily achieved providing that the hanging burr is not too big. This is also a pretty idiot proof method.
Advanced Method
Use a diamond file (usually 600grit) or an Arkansas stone, held flat on the base edge angle to remove the hanging burr - usually a continuous firm slow smooth pushing pass. Your can do this either by hand will the ski on its side in the vice or you can put the ski flat & use the diamond in your base edge angle guide. Done correctly by hand (which is very easy to do & is how the WC techs do it) with a fine diamond there is no risk that you'll alter the base edge angle.
The fine diamond will often throw up a further very fine burr which is then removed by a pass with a gummi held at 45 degrees to the ski base. Note that absolutely no pressure must be applied to the gummi otherwise the edge will be blunted. Hold the gummi very lightly between index finger/thumb & then sit it on the edge under it's own weight without any downward pressure. This is a far more consistent method than just using the basic gummi method but if excessive pressure is applied to the gummi then your hard work can be undone & you'd have been better off using the basic method - so is probably not the solution to use if you're a klutz with tools!
Use a hard gummi stone held flat on the base of the ski - do not try to angle the gummi to the base edge angle. Note that a HARD grade gummi must be used as a soft or medium grade gummi will 'bleed' over the junction of the base/side edge & actually blunt it. A hard grade gummi, when held flat on the base of the ski, has just enough 'give' in it to 'mould' on to the base edge angle to remove the hanging burr but is not so soft as to bleed any further over to cause harm. Good results are easily achieved providing that the hanging burr is not too big. This is also a pretty idiot proof method.
Advanced Method
Use a diamond file (usually 600grit) or an Arkansas stone, held flat on the base edge angle to remove the hanging burr - usually a continuous firm slow smooth pushing pass. Your can do this either by hand will the ski on its side in the vice or you can put the ski flat & use the diamond in your base edge angle guide. Done correctly by hand (which is very easy to do & is how the WC techs do it) with a fine diamond there is no risk that you'll alter the base edge angle.
The fine diamond will often throw up a further very fine burr which is then removed by a pass with a gummi held at 45 degrees to the ski base. Note that absolutely no pressure must be applied to the gummi otherwise the edge will be blunted. Hold the gummi very lightly between index finger/thumb & then sit it on the edge under it's own weight without any downward pressure. This is a far more consistent method than just using the basic gummi method but if excessive pressure is applied to the gummi then your hard work can be undone & you'd have been better off using the basic method - so is probably not the solution to use if you're a klutz with tools!