Choosing and using the best wire brush attachment for rust removal

Don’t just grab the nearest available drill or angle grinder brush attachment. Putting a little thought into choosing the right attachment for the job can lead to better results. In this article we discuss your options, and share some tips for getting extra performance from your brush attachments.

The great advantage of wire brushes over solid abrasive wheels is that they are very unlikely to remove metal or significantly change the profile of the surface. Wire brushes are also non-loading, so they won’t become clogged with material. These advantages often mean that they are ideal for rust removal, as well as deburring, cleaning up fresh welds and general surface preparation before painting.

How do wire brush attachments work?

The word ‘brush’ is not in fact a very accurate name. Rather than ‘brushing’ the surface, wire brush attachments are designed to work like sandblasting. Instead of bombarding the metal with sand, the high-speed rotary action of the drill or grinder causes the tips of the individual brush filaments to hit the surface. It’s like hundreds of tiny hammers blasting the surface.

To use a brush attachment effectively, avoid pressing too hard. This will help to ensure the necessary hammer action at the tips of the filaments, rather than ‘swiping’ the surface with the length of the filaments. Also, applying too much pressure will cause the wires to heat up and shorten brush life.

Crimped or twist knot brushes?

The first factor to consider when choosing your attachment is whether to go for crimped or knot wire brushes:

Crimped wire brushes can be thought of as good light to medium duty tools. The crimping of each wire in the brush is done so that the individual wires act as support for each other.

The main point to bear in mind about a crimped brush is that the wires are separate from each other. The brush remains reasonably flexible during use. Use a crimped wire brush on irregular surfaces where you need good brush flexibility, or if you are concerned that a knot wire brush could damage the metal you are working on.

Twist knot wire brushes are for more heavy-duty work. The wires are twisted together like rope in order to deliver a more aggressive action against the metal surface. This extra firmness and less flexibility make them suitable for removing heavy rust or other contaminates/coatings on the surface.

Steel or stainless steel?

The second choice is whether to use steel or stainless steel brushes:

• Steel brushes are for use on ferrous metals (metal containing iron), including carbon steel, cast iron and wrought iron.
• Stainless steel brushes are for use on stainless steel, and other non-ferrous metals including aluminium, tin and zinc.

It is important that you use only stainless steel brushes on non-ferrous metals, and steel brushes only on ferrous metals. Otherwise, you could create contamination and corrosion by mixing dissimilar metals. It is even recommended that you store the two brush types separately and avoid letting brushes come into contact with the ‘wrong’ type of metal work surface.

Which shape of brush to choose?

Brushes of course come in a variety of shapes:

• Cup brushes. For cleaning large surface areas as they work flat on the surface.
• Wheel brushes. Ideal for smaller, tighter areas as they are designed to work perpendicular to the surface.
• End brushes. Small, compact brushes for getting into holes and other tight spaces.

Which power tool are you using?

Brush attachments are typically manufactured specifically for use with a power drill OR an angle grinder. Obviously make sure you use the right brush with your tool of choice.

When using an angle grinder, you can extend the life of a wire wheel brush by reversing the direction of travel from time to time, as this will self-sharpen the wire tips. Remove the wheel brush, flip it through 180 degrees and refit to achieve this.

One word of caution about using a single speed tool such as a traditional on/off drill or angle grinder. The product information on brush attachments will usually include a ‘Max RPM’ safety rating, so make sure your tool operates at or below this max speed.

Choose from our range of brush attachments

Rustbuster stocks a wide selection of wire brush attachments, from budget brushes to the premium quality ‘Zip Wheel’ range. View our rust removal wire brushes here.