The brushing, etc....
Originally Posted by Richie-Rich
If the ski base becomes burnished, then it will be in fact work hardened. By doing so I speculate that you will markedly reduce the ability of your bases to absorb wax, since porosity will effectually be pressed closed. Any material that is highly porous, such as sintered metal, can be burnished, forged, or shot peened, into a more homogeneous solid material given the required pressure and or heat.
This is just speculation on my part. But if you think of the base as being a plastic lattice network, and then if you were to press into that lattice or rub it to the point that the heat generated began to deform the material such that it began to bond to itself, you can see that the resulting material would be less porous and much more rigid and solid.
...doesn't do much negative to the base, and in the case of brushing, it probably helps maintain the structure. Bases (not edges...we've already been there) do
get case-hardened, less porous, and lose structure one of two ways: (1) Base burn from skiing on super hard, aggressive snow, usually man made or injected. Hot box your skis and generally soak them with wax to help prevent this, also consider using something like Extreme Cold Powder on top of everything. (2) Lots and lots of scraping, especially with a dull scraper...so, obviously, keep your scraper sharp.
If a base does get case hardened, you pretty much need to grind it to open the base up again, then restructure it, re-hotbox it, and so forth.