Sanding is a crucial step in woodworking, metalworking, and many other industries. The type of sanding disc you choose can significantly impact the efficiency and quality of your work. At Empire Abrasives, we understand the importance of using the right sanding disc for the job at hand.
With so many different options available (like type of sanding disc, different abrasive grains, grit size, bonding types, etc.), selecting the right sanding disc can get overwhelming pretty quickly. That's why we've put together this comprehensive guide to help you choose the best sanding disc for your needs. Whether you're a professional fabricator or a DIY enthusiast, we have the knowledge and expertise to guide you through the process.
In this blog post, we will guide you through the process of choosing the right sanding disc, exploring the different types and their applications. We will help you navigate factors like grit size, material compatibility, and disc attachment methods. We'll also provide tips and advice on how to use them safely and effectively. With this helpful guide, you'll have a clear understanding so you can make a better decision when choosing the best disc for sanding, and you'll be able to achieve the best results every time.
In order to determine the best sanding disc for your task, we put together a few questions for you to ask yourself to help narrow down your search.
- What is being sanded?
- What is the material (wood, metal, plastic, etc.)
- What is the condition of the material? (rough, smooth, painted, finished, etc.)
- How big is the work area?
- Is the surface flat or contoured?
- What are your project goals?
- Are you focusing on material removal, smoothing, or polishing?
- Do you need to remove substances like paint or rust?
- What are your sander and disc specifications?
- What type of sander are you using? (Angle grinder, random orbital sander, etc.)
- What attachment method does your sander use? (Backing Pad, Hook-and-loop, PSA adhesive, Roloc, etc.)
Different Types of Sanding Discs
Before we discuss how the different answers to those questions above should affect your decision, we’ll give a brief overview of the different types of sanding discs as well as the different abrasive grains so the recommendations make more sense.
Resin Fiber Discs
Resin fiber discs are made up of abrasive grains bonded with resin to a vulcanized fiber backing. They are cost effective sanding disc used for general purpose grinding and finishing on metals, plastic, and woods.
These discs attach to angle grinders with an appropriate backing pad. Resin fiber discs are heavy-duty and abrasive, and are expertly manufactured for a range of applications ranging from surface blending to heavy stock removal.
Best For: Heavy stock removal, deburring, general sanding, surface blending, and rust removal on metal.
Flap Discs
Flap discs are an innovative type of sanding/grinding wheel popular abrasives among welders and metal fabricators. They are made up of overlapping flaps of coated abrasive cloth strips fixed to a firm backing.
As each layer of abrasives wear down from use, new flaps of untouched abrasive grains come to the top, keeping a consistent cutting performance. Compared with grinding wheels, the flaps give you more flexibility on contoured work pieces and a softer grind.
Specialty Flap Discs:
- Curved Flap Discs: Designed with a unique curved edge, these excel at detailed grinding and finishing, particularly in tight corners and along fillet welds
- Calcium Coated Flap Discs for Aluminum: These discs are designed with a calcium stearate coating that liquefies during use, reducing heat buildup and preventing clogging. This makes them ideal for soft metals like aluminum.
- Mini Flap Discs: Compact yet powerful, 2” and 3” mini flap discs are ideal for intricate grinding and finishing jobs. Their smaller size offers better control and access in tight spaces
Best For: Metal fabrication, weld smoothing, removing mill scale, blending welds, contouring and shaping surfaces, and general sanding/grinding
Recommended Reading -
- T27 vs T29 Flap Disc Differences
- Flap Discs Uses and Differences Guide for a Great Multi-Tool
- Can You Use Flap Discs to Grind Aluminum?
- Flap Discs vs Grinding Wheels: A Side-by-Side Comparison
Hook and Loop Discs
Hook and loop sanding discs are made up of abrasive coated cloth, paper, or film with a backing material similar to Velcro. There are a system of small hooks and loops that are used to affix the sanding disc to the sander. This makes it extremely easy to change the disc, without having to sacrifice on the quality of the disc used. If your sander isn't made to be used with hook and loop sanding discs, you can purchase a converter pad which will enable them to fit on your sander.
Hook & loop discs come in a variety of sizes to fit die grinders up to larger angle grinders. This gives you the ability to cover large areas or narrow in on a smaller detailed sanding task.
Best For: Versatile applications on wood and metal with quick grit changes
Quick Change Discs
Quick change discs are the go-to choice for grinding, deburring, and blending in small areas and tight corners. The simple to use fastening system makes quick change discs the ideal option for users looking to maximize their productivity. These discs are great for grinding, deburring, and blending in tight spaces or on small surfaces
Best For: Precision work, especially on metal and when working in small or hard to reach areas
PSA Discs
PSA (short for pressure sensitive adhesive) sanding discs are very popular among woodworkers and auto body professionals that typically work on flat surfaces. They have a sticky backing that creates a firm attachment to the power sander.
These types of discs are suitable for prolonged usage, with many workshops opting to use them until the abrasive is completely spent.
Best For: Extended use on flat surfaces, particularly wood and metal
Semi-Flexible Discs
Semi-Flexible Discs are heavy-duty grinding discs made with silicon carbide abrasive and a ribbed, semi-flexible backing. These discs are designed for aggressive stock removal on hard materials like stone, concrete, and masonry.
The ribbed design helps channel debris away from the surface, reducing clogging and improving grinding efficiency. Their semi-flexible nature allows them to conform slightly to the surface, making them ideal for uneven materials.
Best For: Heavy grinding on stone, concrete, and masonry
Shop Semi-Flexible Grinding Discs
Surface Conditioning Discs
Surface conditioning discs include a variety of specialized discs for surface preparation and finishing tasks. Unlike the coated abrasives we’ve mentioned so far, they are made up of non-woven webs of nylon fibers impregnated with abrasive grains.
They are used for various metal tasks like rust removal, polishing, and deburring. Their open structure design minimizes loading/clogging, reduces heat build-up, and efficient removal of materials like paint and rust without damaging surfaces.
Best For: Finishing, rust removal, polishing, blending, and surface preparation on metal
Shop Surface Conditioning Discs
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Need Quick Expert Advice?
No matter the job, our sanding discs can help you get it done. If you need assistance with selecting the right product for the job, feel free to call (800-816-3824), email, or chat with one of our experts today.
Abrasive Materials
The abrasive materials are the sharp grains embedded in the disc that do the actual grinding. The different abrasive grains have varying properties that each have their pros and cons. The most common abrasive materials used in sanding discs include aluminum oxide, zirconia alumina, ceramic, and silicon carbide. Then there is non-woven, which has its own pros and cons.
Aluminum Oxide:
Aluminum oxide is the most used material for most abrasive products, including sanding discs. This grain is suitable for sanding and grinding a variety of materials such as wood, most metals, and plastics. It is affordable, versatile, and has good durability. However, it may not be as effective for harder materials such as stainless steel.
Suitable For: Most Ferrous Metals (including cast iron, carbon steel, alloy steel, wrought iron), composites, plastics, and wood
Example - 2" Aluminum Oxide Die Grinder Sanding Discs
Zirconia alumina, aka “Zirc”, is tougher than aluminum oxide and is used for sanding harder materials such as stainless steel, cast iron, and titanium. It has a longer lifespan and is more heat-resistant than aluminum oxide, making it ideal for heavy-duty grinding and sanding applications. Zirconia is also a great choice for high-pressured grinding and machining applications.
Suitable For: Wood, Stainless Steel, Unalloyed Steel, Non Ferrous Metals such as Carbon Steel, Aluminum, Brass, Bronze, Copper, Rubber, and Painted Surfaces
Example - 4-1/2" Curved Flap Disc
Ceramic:
Ceramic abrasive material is designed to handle extremely tough sanding applications. It is ideal for grinding hard metals, such as steel and titanium, ferrous metals, and carbon steel. It is extremely durable, self-sharpening (friable), and resistant to heat, making it a good choice for high-speed grinding.
Suitable For: Super Alloys, Unalloyed Steel, Heat Sensitive Metals like Stainless Steel, Nickel and Cobalt, Aluminum and all Non Ferrous Metals including Copper, Brass, Gold, Silver, and Tin
Example - 4-1/2" Ceramic Resin Fiber Sanding Discs
Diamond:
Diamond abrasives are the most durable and longest lasting abrasive materials. Diamonds are the hardest naturally occurring substances, making them capable of grinding and sanding extremely hard materials such as concrete, stone, and glass. However, diamonds are obviously very expensive, making these the most expensive abrasive material.
Silicon Carbide:
This abrasive material is razor sharp and ranked just slightly below diamonds on the hardness scale. Like ceramic, silicon carbide is also friable/self-sharpening, giving it the ability to have faster removal rates than other abrasives. It is best suited for sanding non-ferrous metals such as brass, copper, and titanium. It is also suitable for grinding glass, plastics, and refinishing hardwood floors. It is known for its aggressive cutting action and excellent finish. However, it is not as durable as other abrasive materials and may wear out quickly.
Suitable For: Marble, Granite, Cement, Stone, Glass, Plastic, Composite, Rubber, Epoxy, Resin, Paint, Fiberglass, Non-Ferrous Metals
Example - 5" Silicon Carbide Sanding Disc
Non-Woven:
Non-woven sanding discs are a bit different than the coated abrasives mentioned above. These discs are constructed with a nylon-webbing, usually impregnated with abrasive grains. They are less abrasive than coated abrasives, making them ideal for finishing surfaces.
Example - 4-1/2" Paint Stripping Wheel
Additional Resources
Choose The Best Sanding Discs for Different Applications
Now that you know more than you ever thought you needed to know about sanding discs, let's go over those questions to determine which disc you should use.
Main Questions to Ask Yourself When Choosing a Sanding Disc
1. What is being sanded?
As you can see in the section above about different abrasive grains, each type is better suited for different surfaces. The condition, size, and shape of the surface will mean different types of discs and grits to choose from.
- What is the material (wood, metal, plastic, etc.)
- Wood: Silicon carbide or aluminum oxide discs work well for wood. If dust is an issue, consider gold sandpaper discs with vac holes. Silicon carbide is preferred for finishing tasks due to its finer grit options and can be used for wet sanding.
- Metal:
- Aluminum Oxide: A great option for general metalworking, including ferrous and non-ferrous metals.
- Zirconia: Best suited for steel and stainless steel, zirc grains are durable and offer a good balance between material removal and longevity.
- Ceramic: Recommended for harder metals, including stainless steel and high-carbon steels. Ceramic is also great for heat sensitive metals.
- Silicon Carbide: Though less common for metal, this abrasive can be used for polishing non-ferrous metals.
- Plastic and Acrylics: These materials can melt or clog abrasive surfaces. Use silicon carbide or aluminum oxide discs with an open coat and lower grit to manage heat and avoid prolonged contact in one area.
- Composite Materials: Grinding composite materials like fiberglass or carbon fiber requires discs that can handle the tough fibers without getting clogged. Film backed sanding discs, or discs with silicon carbide or are often recommended for their ability to cut through these materials efficiently while minimizing heat buildup, which can damage the composite mate.
- What is the condition of the material?
- Rough Surfaces: If the material is rough, you may need a coarse grit disc (below 60) to remove material efficiently.
- Smooth or Finished Surfaces: For smoothing or polishing tasks, finer grit discs (above 320) are usually recommended. Discs like flap discs are excellent for achieving a smooth finish on metals, while silicon carbide is great for polishing wood or other smooth materials.
- Painted or Coated Surfaces: Silicon carbide or ceramic discs are effective, as they can handle the removal of tougher layers without clogging too quickly. Aluminum oxide is also a useful option for a budget-friendly abrasive. Specific paint removal discs like the Black Hawk Abrasives Easy Strip Discs can remove paint without removing as much underlying surface material.
- Rusted Surfaces: Start with strip discs or coarse grits on durable discs for rust removal, followed by finer grits for smoothing and blending the surface.
- What is the size and contour of the surface?
- Large & Flat: Use orbital sanders with hook-and-loop or PSA discs for even sanding. Consider PSA discs for stationary sanders if heavy material removal is needed.
- Small/Intricate & Contoured: Die grinders or rotary tools with smaller, flexible discs (quick-change or Roloc) will be ideal for precision and reaching curves/edges. Flap discs can also be helpful for contouring, especially curved edge flap discs.
2. What Are Your Project Goals?
Your project's end goal, whether it's material removal, surface preparation, or polishing will determine the best grit and type of disc needed.
- Aggressive Material Removal: Coarse grits (below 60) and heavy-duty discs like fiber discs are recommended for aggressive cutting power and durability.
- Paint or Rust Removal: Medium grits (80 to 120) on flap discs, film backed sanding discs, or stripping discs designed to remove paint or rust without damaging the underlying surface are ideal.
- Smoothing or Polishing: Higher grits (above 320) and finer discs, such as finishing discs or buffing pads, are used to achieve a smooth finish.
- Prepping Paint for Wood: Medium to fine grits (100 to 220) are best for preparing wood surfaces for painting, ensuring smoothness without over-sanding.
3. What Type of Sander Are You Using?
Different tools require specific types of sanding discs. First you’ll want to narrow down the types of sanding discs you’d need based on the tools you have available or that you plan to use.
- Angle Grinder: Look for discs with a robust backing that can handle high speeds, such as fiber discs or flap discs.
- Die Grinder: Smaller, more flexible discs like quick-change discs are ideal for the precision work die grinders are known for.
- Orbital Sander: Hook and loop sanding discs are commonly used for their ease of attachment and detachment, suitable for repetitive tasks.
- Rotary Tool: While similar to die grinders in handling detailed tasks, rotary tools are more versatile in the hobby and crafting space, requiring specific smaller diameter discs and various attachments like sanding bands, discs, and brushes for detailed and intricate work.
- Stationary Disc Sander: Primarily used for rapid material removal and smoothing of large surfaces. These will require larger, stationary-specific discs, like a 7 inch PSA sanding disc, that are mounted onto a fixed plate. Ideal for shaping wood, smoothing edges, and other tasks where the workpiece is brought to the tool.
4. What Attachment Method Does Your Sander Use?
The attachment method can influence the ease of use and the efficiency of your sanding tasks.
- Hook and Loop: Uses a Velcro-like (hook and loop) backing to make swapping discs easy. Ideal for tasks requiring multiple grits. Best for orbital sanders and dual-action sanders.
- PSA (Pressure Sensitive Adhesive): Provides a firm attachment for tasks that require more pressure or for stationary sanders. Once adhered, they're less likely to shift during use but are not reusable like hook and loop.
- Backing Plate: Backing plates/pads are necessary for certain types of grinders, ensuring stability and support for fiber discs and PSA discs.
- Quick Change Discs: These discs use a unique roll on disc/ attachment, commonly known as 3M™ Roloc™ fastening system, that allows for rapid and easy swapping without the need for additional tools. The attachment uses an easy twist-on and twist-off motion, making them highly convenient for jobs requiring multiple grit changes or disc types within a short period. They are particularly popular with die grinders and some types of angle grinders, offering a secure fit that minimizes disc slippage during operation.
- Threaded Attachment: Some sanding discs, like flap discs, easily attach to a grinder with a threaded attachment that you directly screw onto the grinder's spindle. This doesn’t require any additional tools or backing plates for attachment
Additional Considerations When Choosing a Sanding Disc
Beyond the basic questions of what you're sanding, your project goals, and your tool specifications, there are a few additional factors to consider that can significantly impact your sanding experience and results.
1. Do You Need to Control Dust?
Dust control can be a big deal in some sanding sessions, especially when working indoors or with materials that generate a lot of fine particles. If dust management is a priority, look for sanding discs that are compatible with dust extraction systems. Discs with vac holes allow for better dust collection when used with a vacuum system, keeping your workspace cleaner and improving air quality. This is particularly important when working with materials like wood or drywall that produce significant amounts of dust.
2. How Much Flexibility Do You Need?
If your project involves contoured or irregular surfaces, consider using flexible discs. Flap discs and surface conditioning discs, for example, offer more flexibility and can adapt to the shape of the material without damaging it. This flexibility helps with tasks like sanding curved metal surfaces, edges, or fillet welds, where rigid discs might cause gouging or uneven finishes.
3. Do You Plan on Wet or Dry Sanding?
Depending on your material and desired finish, you may need to choose between wet and dry sanding. Wet sanding is most commonly used with materials like automotive finishes, metals (especially during polishing), and plastics. It is also often used for materials like stone, glass, and some metals, as it helps to reduce heat buildup and minimize dust. If your project requires wet sanding, make sure to choose discs that are compatible with wet applications, such as silicon carbide discs with a waterproof backing.
4. What’s My Budget and How Long Will I Be Sanding?
Balancing cost with performance is important, especially for large or prolonged projects. Higher-end discs, like those made from ceramic offer excellent durability and cutting efficiency but come at a higher price point. For shorter or less demanding tasks, more affordable options like aluminum oxide discs may be sufficient. Consider the length of your project and how much disc life you need when selecting your abrasives. If you're working on a project that requires extensive sanding, investing in higher-end discs can save you time and money in the long run by reducing the need for frequent disc changes.
Example Scenarios
Choosing the right sanding disc can be overwhelming with so many options to choose from. To simplify the process, you can try answering these scenario-based questions to pinpoint the ideal disc for your project:
Scenario 1: Refinishing a Vintage Metal Table
- Tool: Angle Grinder
- Attachment: Threaded Attachment
- Material: Metal (rusty and painted)
- End Goal: Paint Removal and Polishing
Recommendation: Start with a paint stripping disc for paint and rust removal, followed by a zirconia flap disc for smoothing the surface. Finish with a high grit finishing disc or buffing pad for polishing.
Scenario 2: Restoring a Fiberglass Boat Hull
- Tool: Orbital Sander
- Attachment: Hook and Loop
- Material: Composite Materials (Fiberglass)
- End Goal: Surface Cleaning and Preparation for Repainting
Recommendation: Opt for gold stearate or film backed discs to handle the tough fiberglass without clogging. Start with a medium grit for cleaning and smoothing the hull, then move to a finer grit to prepare the surface for repainting.
Scenario 3: Building and Finishing a Hardwood Tabletop
- Tool: Random Orbital Sander (preferably with dust collection)
- Attachment: PSA
- Material: Hard Wood
- End Goal: Aggressive Material Removal and Prepping Paint for Wood
Recommendation: Begin with coarse-grit aluminum oxide discs for rapid material removal and shaping. Progress to medium and then fine-grit discs to smooth the wood surface thoroughly before applying any finish or paint. If your sander has a dust collection system installed, gold sanding discs with holes will make cleanup much easier and get a better sanding result faster.
Scenario 4: Weld Prep on Steel
- Tool: Angle Grinder
- Attachment: Flap Disc with Threaded Attachment
- Material: Metal (Steel)
- End Goal: Preparing Steel Surfaces for Welding
Recommendation: Zirconia flap discs are highly recommended for weld prep on steel, offering durability and the ability to quickly smooth out imperfections without removing too much material. Start with a medium grit to clean and prep the surface, ensuring optimal weld quality.
Scenario 5: Autobody Paint Removal
- Tool: Orbital Sander
- Attachment: Hook and Loop
- Material: Paint on Metal (Car Body)
- End Goal: Removing Old Paint for Repainting
Recommendation: Strip discs and wet/dry silicon carbide sanding discs are effective for autobody paint removal. For cars with Bondo or autobody filler, green film or gold stearate sanding discs are ideal. Begin with a coarse grit for rapid paint stripping and switch to a finer grit to smooth the surface without damaging the metal. The flexibility of hook and loop attachment allows for quick grit changes, adapting to varying surface conditions.
Tips When Using Sanding Disc
- Different sanding discs require different backing pads. It's important that you use the backing pad that’s compatible with both the machine and the sanding disc you are using.
- Angle grinders and other tools come with guards for a reason. Make sure to always reinstall the guard before turning on your equipment.
- Whenever using sanding discs, it is always important to wear appropriate PPE (Personal Protective Equipment).
- Sanding and grinding release very small particles into the air, some that can be extremely dangerous when inhaled. Make sure to wear a respirator and have good ventilation.
- Let the disc do the work and don't apply too much pressure
- Sanding discs, attachments like backing pads and the actual tool are all rated for different RPMs. It's important to verify all of your equipment works within the same RPM ranges.
- To get the most out of your sanding disc, ensure it is properly cleaned after each use. This can be done with a sanding disc cleaning stick.
Speak with an Expert
Still need help selecting the right sanding discs? Speak with one of our experts about what you’re trying to accomplish, and we’ll recommend the best product for the job. TOLL FREE 800-816-3824.
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