Choosing the Right Abrasives for Welding Projects

The welding abrasive you choose can have a major impact on the success of your welding job. Various types of abrasives are available, though they’re not equally well-suited to every welding project. This article will explain the importance of abrasives and help you make the right choices for a high-quality, efficient weld.

The Importance of Abrasives in Welding

An abrasive is a tough, grainy material used to smooth out or shape a metal surface when welding. It’s essential for preparing and finishing pristine welds and is also effective for repairing errors. Specifically, abrasives have several beneficial functions, including:

• Cutting off sections of metal from stock
• Preparing metal for a clean weld
• Shaping pieces with accuracy
• Grinding away excess material
• Smoothing seams and imperfections
• Creating a polished finish

Examples of Common Abrasive Materials

In general, you should choose an abrasive that’s harder than the metal you’re applying it to. While softer abrasives work well with softer metals or gentler applications like polishing, harder abrasives can handle heavy-duty metals and applications that require more force.

Some of the most common abrasive materials for welding projects include:

• Aluminum oxide: This is a softer abrasive that’s best for polishing and finishing ferrous and softer metals. It’s highly versatile and can be used for various metals used for welding, including steel and stainless steel.
• Silicon carbide: This soft yet sharp abrasive is excellent for polishing, cleaning, finishing and blending stainless steel, brass and copper. This abrasive is well-known for its durability.
• Zirconia alumina: Think of zirconia alumina as a tougher version of aluminum oxide. It’s effective for grinding and sanding harder metals like steel, cast iron and titanium and is ideal in high-pressure applications.
• Ceramic: This is an extremely durable abrasive. It excels at grinding down hard metals like steel, titanium and other tough ferrous metals.

Different Abrasive Products for Welding Projects

The different abrasive materials are formed into abrasive products, which are then applied to welding surfaces by abrasive tools. Each type of abrasive product has a distinct advantage, depending on your welding project.

Grinding Abrasives

The most common abrasive grinding products include depressed center grinding wheels for weld grinding and see-through fiber discs for weld blending. Thanks to their versatility, grinding abrasive tools can be used to achieve precision across many welding tasks.

Cutting Abrasives

These abrasive products include chop saw wheels and cut-off discs and are effective for cutting through various metals. For example, welders can use cutting abrasives for stock removal. While cutting discs are common cutting abrasives, some other welding tools are capable of cutting, such as grinding discs design for both grinding and cutting.

Sanding, Buffing and Polishing

These abrasive products remove imperfections such as burrs from the welding surface and can create a smooth, shiny finish when needed. Some examples include coated abrasive flap discs for deburring, sanding discs for smoothing, and non-woven surface-finishing discs for polishing.

Wire Wheels and Brushes

For cleaning surfaces before a weld and removing imperfections during the project, wire wheels and brushes are the appropriate abrasive products. While wire wheels are compatible with power tools for efficiency, heavy-duty abrasive brushes are manually applied to clean hard-to-reach areas.

How to Find the Correct Abrasive Grit Size

Knowing the proper abrasive grit size helps you achieve a proper weld — “grit” describes how fine or coarse the abrasive particles are and is measured in numbered sizes. As lower grit size indicates a coarser abrasive grit, higher numbers mean a finer grit. For example, a 24 grit is much coarser than an exceptionally fine 320 grit.

It’s possible to have two abrasive products of the same type made from the same material to have both a coarser grit and a finer grit. Therefore, grit is another factor to consider alongside abrasive materials and products. Based on your application, one grit size may be more favorable than another:

• Coarse grits (24 or 36) have the toughness for grinding and stock removal.
• Coarse-to-medium grits (60-80) are best for deburring.
• Medium grits (80-120) are versatile and suitable for surface preparation, light deburring and blending. 
• Medium-to-fine grits (120 and above) are gentle and precise for polishing and finishing.

6 Steps for Choosing the Right Abrasives

Now that you understand the role of abrasives in welding along with the essentials of materials, abrasive products and grit sizes, you’re ready to choose your abrasives. Remember that you may need different abrasives for different tasks during a welding project.

Here are six steps to follow when choosing the right abrasives for welding projects:

1. Choose a compatible material: Ensure the abrasive material is hard enough to work on the material you’re welding. At the same time, it shouldn’t be much harder than you need, or it may damage the weld. Also, check that your abrasive is clean and free of corrosion. To avoid cross-contamination, have dedicated abrasives for different weld materials like steel and aluminum. 
2. Inspect the surface: Are there any imperfections to remove before you begin welding? Choose a suitable abrasive for surface preparation, such as a sanding disc to remove rust or paint or a flap disc for deburring.
3. Determine the grit size: Decide on the right grit size. Use coarser grits for material removal, medium grits for preparing and blending welds and fine grits for finishing.
4. Choose your tool: An angle grinder will serve you well for cutting and grinding applications and pairs well with a flap or fiber disc. If you need a different tool like a blasting machine or want the gentle precision of a hand-applied finish, choose an abrasive product that fits your application method.
5. Keep safety in mind: Ensure you have the proper protective gear for the job. Check your tool and abrasive product for damage before use. Protect yourself against sharp edges, metal debris and toxic welding fumes.
6. Consider your budget: You could save money by using a more affordable abrasive like aluminum oxide. However, the best long-term cost savings will come from using quality abrasives that are well-suited to execute each task with efficiency and optimal durability.

If you have questions about finding and choosing the right abrasives for welding projects, contact one of our welding experts at Meritus Gas Partners.

Choose Meritus Gas Partners for Welding Expertise and Supplies

Are you looking for a reliable, local source for all the welding supplies you need, including abrasives? Meritus Gas Partners is a nationwide network of industry-leading welding gas and supplies distributors. Our independently run partners offer the care, attention and exceptional personalized service of a local small-to-midsize business, plus the resources of a national network. 

Find our distributors in your area for the selection of quality abrasives and the industry expertise you need.