How to choose the right abrasive for any job

Abrasives are materials – usually a mineral – that are assembled onto different types of backing such as paper, fabric, fibre, and cloth. The chances are you’ve used an abrasive before, and one of the most common types is sandpaper.

When rubbed against something, abrasives help to shape or finish a surface and they’re used in various processes to polish, refine and cut.

Here are just a few jobs you might need an abrasive for:

• Car body repairs
• Marine and composites
• Wood and furniture
• Building and decoration

Whether it’s removing a scratch or preparing a surface for a coat of paint, abrasives are needed for various tasks.

However, not all abrasives can be used for the same job. For example, heavy-duty sanding requires a rough abrasive which creates a deep scratch pattern, whereas a fine grain would be more appropriate for creating a smooth finish. So, it’s important to find the right one for your needs and using the most suitable abrasive will help achieve the desired result. This is especially the case for car body repairs where, now more than ever, the quality of finish relies on the quality of preparation from the start.

There are three distinct stages to surface and car body repairs and abrasives generally fall under one of these categories:

Preparation

The key to a successful job is preparation, and this stage is all about preparing a surface. For example, when completing car body repairs, you might need to start by using an abrasive to remove paint, a scratch or rust. Sometimes, filler will be required to restore a surface to its original shape, and this will also need preparing with an abrasive. At this stage, an abrasive with a larger mineral is required as these provide a deeper cut.

Directions of use: Try to work in a linear action and apply uniform pressure for best results (this guidance will vary depending on the product, so check the manufacturer’s instructions).

Prime

Once you’ve prepared the surface by getting rid of a scratch or paint, it’s time to prime the area ready for painting.

For most jobs like repairing car bodywork, multiple coats of primer need to be added to the surface before paint can be applied. An abrasive can then be used to smooth the primer ready for painting.

Directions of use: Work in a linear action and apply uniform pressure throughout the abrasive for best results (this will vary depending on the product, so check the manufacturer’s instructions).

Paint

The final stage for most surface and car body repairs is painting. Here, abrasives can be used between coats to smooth the surface or once all coats have been applied to help complete the job. This stage is all about smoothing the surface and only requires an abrasive with a smaller grain. Always follow the manufacturer’s instructions.

So, how do you know which abrasive is suitable for each of these jobs?

Most abrasives sold by Halfords are graded by FEPA (Federation of European Producers of Abrasives). The FEPA system grades abrasives based on the size of the grains used and this then indicates what a certain abrasive can be used for. This grade will begin with a P and end in a number, for example P60, and the smaller the number the larger the grain. The below table shows these grades and is handily split into preparation, prime and paint categories to make it easier to find the right product for your needs. We’ve also added abrasives that don’t use grains and therefore don’t have a FEPA grade.