Friday, October 3, 2014

Grinding Season - How much p-tex is removed?

People often ask how much p-tex is removed from the ski during the grinding process.

During the total ski servicing process, there is p-tex removed while steel scraping (before the ski ever goes through the grinder), and then of course during the grinding process.   MOST of the p-tex comes off during the steel scraping part of the process.   The steel scraping is where the bulk of the flattening and scratch removal is done.   (My educated guess is that 80% of the p-tex removal occurs during the steel scraping and the other 20% of p-tex removal is done by the grinder)

While working on a few skis today, I decided it would be a good time to make some measurements.
I collected the p-tex shavings from the steel scraping process for 20 pairs of skis.   None of these were new skis, and it was an assortment of Madshus, Rossignol, Salomon, Atomic, and Fischer skis.   Pretty much a random sample of skis in decent shape.

P-tex shavings from 20 pairs of skis.   About 2.35 grams per ski.
The photo shows a pretty scary big pile of p-tex shavings.   Note the 12 ounce coffee cup and office-sized stapler in the photo to provide a bit of scale.

From 20 pairs I collected 94 grams of dry p-tex shavings.    That's about 2.35 grams per ski.   For comparison, that is about the same weight as half a teaspoon of regular granulated white sugar.     If my estimate is close on the ratio of p-tex removed in the grinder, then about 2/3 gram is removed per ski in the grinder, with a total of approximately 3 grams per ski is taken off.

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