When it comes to selecting the correct sanding disc for your project, a key consideration to keep in mind is which abrasive to use. Whether you're working with wood, fabricating metal, or smoothing welds, you'll want to be sure to select the right sanding disc abrasive for the job to maximize your output while minimizing your cost. This guide will also look at some other key factors to consider when selecting a sanding disc.
Decisions about which sanding disc to choose for your project must first take into account the composition of the abrasives adhered to the disc, as well as the type of disc.
Composition of Sanding Discs
Early sanding discs and abrasive sheets such as sandpaper were composed of natural materials like garnet, flint, pumice, and emery adhered to a paper backing with varnish or glue. Today's more modern abrasive discs feature man-made synthetic materials such as silicon carbide, aluminum oxide, ceramic, and others. Man-made materials allow for greater control over tolerances, sizes, and capabilities which makes for higher-quality abrasive discs. These materials can be made to exact sizes, will maintain abrasive properties longer, and have greater heat resistance to allow them to withstand tremendous machining speeds.
Types of Sanding Discs
Just as abrasive materials have evolved with time, the types of sanding discs have changed as well. Today, we have more systems for the interfacing of the disc to the pad, and the selection of each backing interface can depend on the roughness of the surface to be sanded as well as the pressure to be applied. The most commonly used disc types are pressure-sensitive adhesive (PSA) discs, adhesive discs, or hook loop (think Velcro) sanding discs. PSA discs feature a hole-free design to reduce tearing, and an anti-clog zinc stearate coating to resist dust build-up. Hook-and-loop discs feature tiny plastic hooks and loops used to attach the abrasive disc to the tool. Both provide secure mounting of the abrasive material to the sanding pad, and each also offers the opportunity for a quick change-out if the abrasive material wears out and needs to be replaced, or if it's time to work with another grit. It is possible for the sanding pad to wear out on a hook-and-loop tool, but don't worry, the pad can be easily replaced.
With the wide variety of sanding discs available, from flap discs to floor sanding discs for different applications ranging from finishing and blending to grinding and floor polishing, it can sometimes be confusing to know which disc to choose for which job. Here's a look at popular discs and how to use them.
- Fiber Discs: These are ideal for general-purpose applications ranging from heavy stock removal to surface blending. Featuring a heavy-duty coated abrasive disc, fiber discs can be used with a back-up pad on portable angle grinders for paint and rust removal, deburring, portable grinding, cleaning, and detailing in industries including collision repair, metal fabrication/welding, and manufacturing/industry.
- Flap Discs: With abrasive flaps affixed to a rigid backing plate, flap discs can be used with right angle grinders to grind and finish at the same time. They're great to use for stock and material removal during blending work as well as for beveling, finishing, and cleaning and detailing work. Flap discs are frequently used in building and construction, auto repair work, as well as energy and transportation industries.
- Paper Discs: Likely the most common and widely known sanding disc, these are traditional dry sanding discs used with random orbital and rotary sanders. They are used for light stock removal to fine finishing on wood, plastic, fiberglass, composite, primer and sealers. Paper discs are typically available in PSA and hook & loop styles, and are tremendously versatile in a wide range of grits. They can be used for paint preparation and removal, sanding, smoothing, and stripping. Paper discs are also good for rust and stock removal, along with blending, finishing, and microfinishing. Often they're used in collision repair, home and leisure projects, paint and drywall operations, manufacturing, industry, and more.
- Film Discs: With a polyester film backing featuring exceptional flexibility, tear resistance, and flatness for a great finish, film discs are designed for final finishing on primed and painted surfaces, composites, and varnishes. With a hook & loop backing and aluminum oxide abrasive, film discs are used for finishing and microfinishing in collision repair, transportation, and manufacturing and industry.
- Cloth Discs: Frequently used on random orbital and stationary disc sanders, cloth discs are ideal for blending, paint prep, polishing, stock removal, and stripping for collision repair jobs, home and leisure projects, metal fabrication, welding, building and construction, and more. With a PSA or hook & loop backing, when paired with a rubber back-up pad, it provides the rigidity needed for hard-to-grind steels and alloys.
- Quick-Change Discs: With a twist-on/twist-off fastening system and tool-free attachment design that saves time and maximizes productivity, quick-change discs offer excellent blending, deburring, and grinding into smaller, hard-to-reach areas. Used with portable grinders and disc sanders, quick-change discs can be used for paint prep and removal, body panel surface repair, finishing and deburring, stock and rust removal, blending and beveling, surface prep, and grinding. Quick-change discs are ideal for use in collision repair, janitorial work, metal fabrication, welding, and in industries such as transportation, energy and environment, electronics, medical, and manufacturing.
- Surface Conditioning Discs: Use with portable grinders and disc sanders, along with bench, pedestal, and floorstand grinders, and rotary floor buffers. Ideal for a variety of applications, including body panel surface repair, floor sanding, paint prep and removal, parting line removal, stock and rust removal, and portable and surface grinding. Surface conditioning discs are often used in manufacturing and industry, medical, transportation, energy and environment markets, the janitorial sector, and collision repair. These versatile discs are attached by hook & loop, speed-lok or speed-change fastener, and center-mount fastener.
- Foam Discs: Used in collision repair, manufacturing and industry, and transportation applications, foam discs are designed for moist finishing clear coats, varnishes, and gel coats to deliver a semi-polished surface. This provides for quick and easy buff outs on fiberglass and composite finishes. The foam backing is designed to conform to material contours during use.
- Floor Sanding Discs: These are designed to create a flatter surface and finer finish on floors compared to traditional belt or drum machines. Used with portable disc sanders or floor sanding and maintenance equipment, they're the disc of choice for commercial floor sanding professionals, and are popular in the building and construction industries, as well as for home use.
- Edger Discs: Along with floor sanding discs, edger discs provide the final touches to hard-to-reach areas of hardwood floors that belt and drum machines can't access.
- Diamond Discs: For use on fiberglass and composite surfaces, diamond discs feature the aggressiveness and durability of diamonds on a flexible backing. Used in a variety of manufacturing applications, they're commonly used with portable right angle grinders or random orbital disc sanders.
- Net Discs: With an open mesh backing, net discs provide a cleaner, healthier work environment with less sanding dust released into the air. Ideal for paint and drywall work, collision repair, metal fabrication, building and construction, floor sanding, and more, net discs are often used with portable disc sanders, floor sanding and maintenance equipment, and even hand-held sanding blocks. A versatile disc, it's used for applications including smoothing and stripping, plastic structural and cosmetic repairs, paint removal, cleaning and detailing, blending, and body filling.
Sanding Disc Grit
“Grit” is a commonly used word to refer to both the type and size of the abrasive on the disc. Sizes are rated on a numerical scale which can range from coarse (60) to super fine (600). A lower grit number indicates larger pieces of grit on the disc surface and more aggressive material removal. Conversely, a higher grit number indicates smaller, finer pieces of grit providing for a smoother finish. While there are a wide variety of different discs for specific jobs, ranging from fiber discs to floor sanding discs, disc grit is always a key factor to consider when selecting the right disc for your job. Regardless of the grit material, it's important to remember that when using a sanding disc, sanding is actually a cutting process. So, each particle of grit material on the disc surface is a tiny cutter attached to your disc sander. And keep in mind that sanding discs and grits are best used in succession, where each progressive grit removes the scratch pattern left from the previous one until the ultimate, final smooth finish is achieved.
Whatever the job you're doing, selecting the right abrasive sanding disc with the correct characteristics to complete the job is critical. Remember, the use of sanding discs is often a step-by-step process with each successive disc providing a smoother result. Choose the right one, take your time, and you'll most certainly be happy with the results.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.