Looking at the Nitty-Gritty

Caylena Cahill

In general, the goal of sanding is to produce the least amount of heat possible. This heat will cause the resins in woods, paints, and glues to melt and become gummy and stay on the sandpaper, along with the sanding dust and any other stray particles. Doing so will result in a better finish and a longer lifespan for your abrasives and, therefore, a lower cost for supplies. Knowing the properties of the material will help you optimize this. Next, you need to know the nitty-gritty details about your sandpaper.

Grains:

When it comes to friability, not all grains are created equal. Some grains will become dull. When a grain becomes dull, that can create an uneven or blotchy finish. Aluminum oxide is recommended for most lower-grit to medium-grit applications, and silicon carbide or aluminum oxide for some finishing or higher-grit applications.

Backings:

Coated abrasives can be made on different substrates; each offers various advantages and disadvantages. 

  • Paper generally offers one of the best finishes but can be easily torn. Depending on the thickness of the paper, it can be more or less flexible and more or less durable. 
  • Cloth products are often quite durable and can be used for heavy-duty machine sanding. Because the cloth used in these products contains a weave, this can cause an uneven scratch that could cause issues in the finish.
  • Film is used for coated abrasives is generally seen to be the optimal combination of durability and flexibility for sanding discs. It provides a flat surface for the grains while also being resistant to tearing and bending to match profiles.
  • Foam sponges can be used on white wood, but they’re used more frequently for finishing applications, such as sanding between coats of finish. 

Coatings:

‘Coatings’ refers to the percentage of space on the backing covered with grain. An open coat has the most open space and least grain coverage, allowing for a cooler sanding experience and less loading. A closed coat has the most grain coverage. This will produce a more even scratch and a better finish. It’s also good for heavier stock removal since more grains are present to do the cutting.

Fillers and Chemical Coatings:

Stearate is an external coating on some coated abrasives. It acts as a lubricant to reduce friction while sanding. Besides reducing heat, another benefit to reducing friction is reducing the opportunity for static to occur. Static electricity can be a big problem when sanding, as it can cause dust extraction to run amok. 

Grits:

Coated abrasives come in various grits, starting as low as P8 and going to P1200. Before making a product selection, it’s key to understand the basics of coated abrasives.

When it comes to navigating the world of coated abrasives, there are many variables to consider, and it can be complicated to identify the best solution to meet your needs. This article just scratches the surface (no pun intended!) of these products.

Caylena Cahill is Uneeda’s Creative Director.

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