I had intended on doing that when referring to crafters that were masters of a certain type of crafting, which in essence is part of the problem i face. I don't want a fellow JB fan to flame me when I call someone in my book a earthcrafter, or a woodcrafter, because they are the same terms used by JB in Codex.
Again, use roots of words. Roots of words are more forgiving than just the word in the base language. It might take some practice to find the correct one to use though.
Greek and Latin would be the easiest, since English inherits alot from those languages. This would also allow the average Enligsh-speaking reader to pick up on what the person does almost instantly.
Going off that, Firecraft could be Pyrocraft or Ignicraft. Though Ignicraft sounds funny.
You might experiment with roots from other languages or make up new roots to stand in for fire, wood or whatever.
Another option would be to put yourself into the shoes of someone who lives in your would. What do they call it?
A Pyrocrafter could be called a Fireman.
But, I have a personal interest in Slang so that suggestion's biased.