Different abrasive grains have different properties and the best grain type for sanding will largely depend on the material you’re sanding. While hardwood is the most popular option for cabinet frames (due to its durability), cabinets can be produced with either hardwoods or softwoods. We recommend different grain types and coatings depending on whether you’re sanding softwoods or hardwoods. 

As a lower-density material, softwoods are one of the easiest materials to sand. You don’t need to use a very strong abrasive grain. In fact, you may find that it’s too easy to accidentally remove too much material with a high-strength grain like ceramic. We recommend open-coat aluminum oxide for softwoods. Aluminum oxide does a great job of sanding wood and the open coating provides more airflow to prevent debris from clogging up your discs or rolls. 

As a denser material, hardwood requires more strength to sand. You can still use aluminum oxide, but you’ll want to use closed-coat aluminum oxide. The closed coating provides greater grain coverage over the surface area of the backing, which provides a more aggressive cut. Zirconia is another popular choice for sanding hardwood. Zirconia rolls and discs are more expensive than aluminum oxide rolls and discs, but Zirconia is a stronger abrasive grain. It will last longer and sand faster to save you time and money in the long run.