Originally Posted by John J
We all talk about the bases absorbing wax.
How deep does wax actually go in a sintered base?
I've looked through Dominator and Swix materials.
If the surface of the P-tex was absolutely smooth on a microscopic scale, as a previous poster said, the wax would go in a negligible distance (ie, less than a micron). Any thicker layer would quickly get either intentionally scraped off or skied off.
However, since the P-tex surface is not smooth on a microscopic scale, the wax fills in the spaces between the very tightly but randomly spaced peaks and valleys that occur during manufacturing and/or base prep. After the wax is scraped and/or slightly skied on, much of it will remain in these microscopic valleys because the ski will be riding on the P-tex peaks, and the valleys won't get scraped as much.
However, just like the P-tex has microscopic peaks and valleys, there are always microscopically sharp dendrites and facets on the top surface of the snow, and these will eventually poke down into the microscopic valleys of the P-tex and scour even the bottom of those valleys. This is why a thick unscraped layer of wax will get skied off in a run or two, but the remainder will usually last for a few days of regular skiing.
The microscopic peaks and valleys in the P-tex are much larger than a micron, but still quite small. I have a low power inspection microscope at home and looking at one pr of skis (the ones with the least wax), it looks like the "vertical" of this P-tex base is highly variable, but somewhere between 25 and 100 microns (ie, 1 to 4 mils or 0.001" to 0.004"), so the wax layer should be about the same thickness. Obviously, it will vary tremendously with base prep / structuring.
In addition, the wax needs to have a low viscosity for it to flow into the bottoms of such small valleys. This can only happen if it is hot when it is applied. If it is merely penciled on cold, it only gets deposited on the tips of the microscopic peaks in the P-tex, and thus does not work as well.
Tom / PM