Sand Paper

What is Grit?

Grit is the density of abrasive material attached to the backing of the sandpaper.

Low grit numbers equal rougher grit, why?

Lower grit numbers represent coarser abrasives that scrape off materials much quicker.

High grit numbers equal smoother grit, why?

The higher grit number is equivalent to a finer abrasive, which creates smoother surface finishes.

What types of sandpaper are there?

Garnet is good for hand-sanding. It works well on raw wood, removing light scratches and preparing the surface for finishing. The abrasive particles break during use, providing new edges for removing material but garnet sandpaper wears quickly.

Emery works for both hand-sanding and power-sanding metal. Use coarse grits to remove rust or paint, and finer grits to polish. Emery cloth sandpaper has a cloth backing.

Aluminum oxide is a common sandpaper type that works on wood, plastic, metal and drywall. The particles break during sanding, constantly exposing new, sharp edges. Aluminum oxide sandpaper is long-lasting, making it a popular choice for power-sanding, and you can also use it for hand-sanding.

Silicon carbide sandpaper removes material more quickly than aluminum oxide but doesn't last as long. Use it on wood, plastic and metal for tasks such as rough-sanding, removing paint or rust, and sanding between coats when finishing. Silicon carbide products often have a waterproof backing that you can use for wet-sanding, which is a good technique for minimizing scratches when applying liquid to lubricate the work surface.

Zirconia alumina is suitable for wood, fiberglass, metal and painted surfaces. You'll find it in the form of belts, pads and discs for power-sanding. Like garnet and aluminum oxide abrasives, the particles break during use, maintaining sharp edges that remove material quickly. Zirconia alumina lasts longer than aluminum oxide.

Ceramic alumina is available in belts and discs for power-sanding and is good for aggressive material removal on wood.

What is "Wet sanding?

Wet-sanding is using a lubricant (water, soap and water, or other) along with the sand paper to sand. It helps to prevent the sandpaper from clogging with dust, remove loose abrasive particles and reduce airborne dust.

What is Sand sealer and what does it do?

Sanding sealer is lacquer, or some other basic coating, with zinc stearate added. The stearate, which is a soft, fluffy soap, adds loft to the lacquer, making it build up and fill in pores much faster. It also makes the lacquer softer, and acts as a lubricant when sanding, so that sanding sealer powders off quickly and easily.

Sanding techniques

Pre-Sand: roughing, knock of edges. Use lower grit numbers, p80/100
Mid-Sand: sanding in-between steps, getting large scratches out. Medium low-high grit numbers. Ie :p120/220

Post-Sand: Finishing sand, getting to the smoothness desired. P400 and higher