In english, the terms used to describe some of the materials speak for themselves, so that the reader don't need specific knowledge about skiing to understand them. Take for instance ski iron or base cleaner...
However, the official french translation of these terms uses a ski tuning-based concept : "farter". It's basically the idea of ski tuning. So, to use the examples cited above, we talk about "fer à farter" or "fart en spray".

If an experienced skier will be familiar with this concept, a french person who knows little to nothing about skiing would be lost for this first tuning, for this word would sound rather strange. I wondered if I had to add a "farter" definition in the glossary.

I asked my coworker who was mainly geared by this instruction guide (if it was confirmed or beginner skiier) here is his answer:

Camille,

Perfect! How was the translation? Its mainly geared toward people who have some knowledge regarding skiing. Hope this helps!!

Scott

Thus, I decided I will leave "farter" as it is and not add more definitions, since the reader is supposed to have some global knowledge about skiing.
However, since "mainly" doesn't mean "only", I also decided not to use this term unless there is no other term that can be used. "Farter" may seem familiar to those that are used to skiing (and still, not always), but using this possibily strange-looking term too often may discourage the reader, and may have the whole instructions guide looking more complicated that it actually is.