Originally Posted by RShea
I was told the theory is to go course to fine in polishing. I start with a diamond (does not take much material compared to a file) to get rid of the burs and then a stone for further deburring and polishing. Once a fine stone is going down the ski smoothly, if you look at the edge there still may be a few spots that have minor discolorations (if they ever had a little rust) or pitted marks, or scallops as one poster called them- and a rough to fine sand paper will make them smoother and more polished.
How in the world are you using sandpaper on your side edges without dulling the "corner"? What are you using to guide the paper? You see the paper "compresses" a bit and allows the grit to overlap to the base side of the edge at the same time as the side. I think you're really dulling your edge with this technique.
Honestly, I don't know anyone using sandpaper for side edge preparation. You're also using your tools in the wrong order (in my opinion). So here's what you should be doing:
1. From a totally ground flat ski - set the base bevel with the best "fine" 8" flat file and guide you can buy (or have the shop do it - base bevels are very sensitive and if you don't know how to do this right you're going to screw up your skis).
2. Cut back the sidewall with a skyver or a 7 degree guide so that it doesn't interfere with edge sharpening.
3. Using a 3 degree guide, set the side edges bevels with a high quality pansar file.
4. Polish the side edges with progressive grits of diamond files (I use Moonflex 100 through 1500 - a bit overkill, but leaves a great finish) using a guide.
5. Polish the base edges with progressive grits of diamond files (same Moonflex stuff again) using the guide.
This should leave you with an ultra-sharp edge finish with absolutely NO edge burr.
Note that I like to use stones to knock out rock damage and burrs BEFORE my diamond files go near the edge - protect your investment in quality diamond files - it's not necessary to put them through that kind of abuse.