Keep in mind that form faces are not perfectly flat, so the narrower the scraper, the finer cleaning you will get.
For over 25 years we have utilized carbide blades in our scrapers. Carbide is one of the hardest elements available and has the ability to stay sharp for extended uses. The C-2 carbide used by Hartman Scrapers has a Rockwell hardness of 90 – this is a harder carbide which will stay sharp the longest.
We have recently introduced heat treated D-2 tool steel blades as a less expensive option to our carbide blades. Our heat treated (hardened) tool steel has a Rockwell hardness of 60. While it will not stay sharp as long as the carbide, it is much less likely to chip, and is much easier to locate local re-sharpening service.
*When using carbide blades remember to be sure to only use it as a scraper. The hardness of carbide that helps it stay sharp also makes it brittle. If you get in a hurry and turn the handle in your fist and use it as a chipping hammer you will prematurely chip or crack the carbide, and greatly reduce the life of the blade, and the ability to re-sharpen it.