I just thought I'd share how I made myself an inexpensive sharpener for my plastic wax scraper. My first scraper was a plastic wall switch cover that I sharpened with a normal file When that broke, I graduated to a scrap piece of 1/4" thick plexiglas that I sharpened with the same file. But the file was too fine and took too long, and also it was hard to hold the scraper upright when pulling it across the file.
I saw the commercial Toko scraper sharpener that sells for around $50, which I thought was pretty steep. But then I noticed Slidewright had a 12" panzer file for the modest price of $13, so I got one of those (along with a bunch of other stuff -- thanks Terry :-) and screwed the file to a piece of wood to which a bit of 2x4 was also attached as a right-angle guide. (The holes in the file were already there -- how convenient!) Here's what it looks like.
To use it, I first lay the scraper flat on the file and pull it across on each side, then I hold the scraper against the guide and pull the edge across the file. It works great!
Not only that, but I got the warm, fuzzy feeling of making something myself and saving a few bucks. And if I ever want to use the file for some other purpose, I can easily take it off.