January 08, 2014

Why do some woodworking shops use Silicon Carbide paper wide belts?

We’ve been supplying sanding belts to the woodworking industry for 29 years now and the “traditional” belt recommended for wood sanding has always been an aluminum oxide, open coat belt.  It is the most common, all-purpose woodworking abrasive, and for good reason. It is the only abrasive mineral that fragments under the heat and pressure generated by sanding wood. This characteristic is called friability and is highly desirable. As you sand, aluminum oxide renews its cutting edges constantly, staying sharp and cutting much longer than other minerals. Aluminum oxide is also a relatively tough abrasive, which means that its edges won't dull much before they fragment. Its friability and toughness make aluminum oxide the longest lasting and the most economical mineral for wood sanding applications.

But sometimes life or price isn’t the determining factor.  In recent years, higher end woodworking plants have started to incorporate Silicon Carbide paper-backed belts into their wide belt finishing line. Why, you ask? Well, here are some of the properties of a silicon carbide paper belt that are beneficial to woodworking:

  1. Different types of abrasive minerals will stain differently. The same grit belts of Silicon Carbide will stain differently than Aluminum Oxide, with a lighter color gradient than when sanded with the traditional Aluminum Oxide belts.
  2. Silicon Carbide is sharper than Aluminum Oxide, and is effective at removing the “hairs” that is the result of the wood fibers being bent instead of cleanly cut by an Aluminum Oxide belt. These fibers then “stand up” after staining and contribute to a blotchy finish.  Common practice is now to belt sand with Aluminum Oxide in your coarser grits, and then switch to Silicon Carbide for your finer grits to eliminate any fuzziness that was created by sanding with the AO belts.
  3. Paper backed belts have a flatter substrate, so the grain height is much more exact over the whole surface than cloth backed belts.  All of the grit starts and ends at the same height—you don’t have the potential for variation like you do when some of the grain sits on top of the cloth threads versus in between the cross-hatched woven cloth threads.
  4. Finally, paper belts run cooler—they dissipate the heat more effectively than cloth belts. And less
    heat=less glazing of the mineral as it wears down & higher quality cutting, which contributes to a finer finish.

Basically, it comes down to finish. Silicon Carbide belts may not last quite as long, and they usually cost more than Aluminum Oxide belts—but they are the preferred wide belt for final finishes in a lot of professional cabinet shops and furniture manufacturers!

Interested in ordering sanding belts?. Just give us a call at 800-814-7358 or contact us through our website.

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