September 2020 Issue

Wire brushes are a staple for weld cleaning. They’re versatile and effective tools for removing surface contamination, such as rust or heat discoloration, without removing base material. There are many types and styles of wire brush – each with its own benefits and best practices for use. Choosing the right one for the application, and following some good advice, can improve productivity and quality in weld cleaning.

Wire brush options

Every welder understands that most welding applications require pre-weld, interpass and post-weld cleaning. And when it comes down to surface prep and finishing, wire brushes provide

Wire brushes can provide efficient weld cleaning without removing base material in many applications.

efficient cleaning action without removing base material. The main types of wire brushes used for weld cleaning are wheel, cup, end and hand brushes.

  • Wheel brushes are the workhorses of wire brushes. They offer great versatility for many pre-weld, interpass and post-weld cleaning jobs.
  • Cup brushes are good for weld preparation, especially for cleaning a larger area or wide surface. These brushes aren’t typically used for interpass weld cleaning because of their size.
  • End brushes can be used for cleaning tight, hard-to-reach areas such as T-joints. End brushes with fine, crimped wires are good for light surface cleaning on TIG welds as well.
  • Hand brushes can be used for small welds to knock off slag with a few swipes between weld passes. But using a handheld brush to clean a larger weld is very inefficient.

Each type of wire brush is available in various configurations, including knotted and crimped wire. When a straight wire is twisted into a knot, the wire becomes stiffer and, therefore, more aggressive.

The general rule of thumb is the tighter the twist of the wire, the more aggressively it cleans. If the tuft at the top of the knot is spread out, the wider face width is good for cleaning a larger surface area. If the knot is twisted tightly all the way to the top – without a tuft – the cleaning action is more aggressive, which can be good for cleaning V-groove welds. Compared to a knotted wire, a crimped wire offers more flexibility but is less aggressive.

It’s recommended to use the finest wire gauge possible that still gets the job done. Fine stainless steel wire is well-suited for cleaning aluminum, stainless steel and TIG welds. Using a heavy-gauge wire on aluminum can alter the base material and change the appearance of the material, but a fine wire removes discoloration without removing base material.

Choosing the brush

Several factors play a role in choosing the right wire brush for the job, including the type and size of the weld being cleaned, the base material and the desired surface finish.

It’s critical for productivity and quality to match the wire brush to the base material type. A stainless steel brush should be used on any type of stainless steel or aluminum. Using a carbon steel brush on those materials can cause contamination or after-rust and will require rework.

It’s also important to consider the size of the surface to be cleaned. A handheld brush may be sufficient for knocking the slag off a small area while a right-angle grinder is typically better suited for cleaning a larger area or a root or fill pass on a pipe weld. A cup brush can be a good choice for efficiently cleaning a very large area, such as plate steel.

If the area to be cleaned is small or hard to access, a right-angle grinder may not work. A die grinder with a small diameter end brush might be a better choice.

Another question is how aggressive the product needs to be. To remove thick slag or rust, a more aggressive wire brush is likely needed. For simply removing discoloration, a die grinder with a fine wire brush may do the trick.

Fast tips

Occasionally flipping a wheel brush helps keep the wire tips sharp to maximize cutting ability and performance. Weiler’s Dually is designed to make flipping the wheel quick and easy.

No matter the brush choice, avoiding some common mistakes can help improve productivity and efficiency. Follow these tips for faster weld cleaning when using wire brushes.

Monitor tool power. Whether it’s air-powered or electric tools, too little power hampers productivity. The faster a tool rotates, the more the wire tips come into contact with the surface and the faster the brush cleans. Choose an electric tool with higher amperage to better maintain the rpm rating of the tool. Also, minimize extension cord length and use an appropriate gauge of extension cord to adequately meet the load requirements.

Air tools also have rated speeds, but they can be adjusted to the appropriate speed for what’s being cleaned. It’s important to monitor air pressure when using air tools. If the tool requires 90 psi but is receiving less, it won’t turn at the necessary speed to clean effectively.

Use proper pressure and orientation. With wire brushes, the wire tips are what do the work. Operators may think they can clean faster by applying more pressure, but too much pressure can actually work against them by putting pressure on the sides of the wires and causing them to break. This slows cleaning and poses a safety hazard. It may be especially tempting to use more pressure with thinner gauge wire, which is less aggressive than thicker wire. But using the finest wire gauge possible for the job delivers efficiency because there are more wire points to do the cleaning.

wire tip
With wire brushes, the wire tips are what do the work. Applying too much pressure can put pressure on the sides of the wires and cause them to break.

Proper orientation of the brush to the work surface also affects cleaning efficiency. Hold the power tool so that only the tips of the wires – not the sides – hit the work surface.

Rotate the brush. When wire tips become dull, they clean more slowly. When using a wheel brush, occasionally flip the wheel to help keep the tips sharp to maximize cutting ability and performance. Look for a product that’s designed to make flipping the wheel quick and easy.

Monitor brush life. Wire brushes wear over time. As a wheel brush diameter gets smaller, the brush becomes less efficient. Wire breakage also impacts performance because fewer wire points hitting the surface means less cleaning. Any brush with wire breakage should be discarded to maximize safety and efficiency.

Store brushes properly. Tools and brushes should be stored in a clean, dry place. It’s a good practice to remove the brush from the power tool when not in use and store it in its original packaging. This helps maintain the wire integrity longer, which contributes to more efficient performance.

Saving even a few minutes with each weld cleaning can add up over time in the welding operation. Choose the right wire brush for the job and follow these best practices to optimize performance and efficiency when using them.

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