What Grit Sandpaper For Touch-up Car Painting?

What Grit Sandpaper For Touch-up Car Painting?

Touching up your car's paint, even with the many clever and easy to use solutions that we have these days at our disposal, is always a nerve-racking ordeal. Everything rushes through your head at once; are you using the right paint for the job, or whether you're even putting it on properly. Am I painting too much over the lines, or do I need to wax the car down after this

This is made more anxious after you suddenly remembered someone mentioning sanding your car. Well, it turns out that a bit of gritty sanding helps a lot to smoothen out the damaged or chipped paintwork. Overall, this makes it both easier to touch up, and may improve the final look of the now-repaired bodywork. But what grit of sandpaper should you be using for paint touch-ups

A Few Gritty Facts That You Should Know

Before we dive deeper, however, what exactly is grit? In sandpaper, 'grit' defines how much abrasive material in individual pieces you have per square inch of paper. For example, 1,000 pieces of grit on one square inch of sandpaper would equate to 1,000-grit sandpaper. Something else we'll learn through this is that the higher the grit number is, the finer (less coarse) the sandpaper will be

In automotive applications, the grit rating can vary anywhere from a scratchy 40 grit, to a very fine 3,000 grit. It's crucial to understand the differences, as either end of the grit spectrum has its use for car repairs. Here's a breakdown of the most common grit ratings on sandpaper that you may come across

40 grit - These are as coarse as sandpaper can be, for the most part. For 40 grit, it's a very rough surface that will leave sanding marks, often used to prep the bodywork before any paint or material even goes on it. It's very handy to have when say, you're trying to remove deep rust before any body filler is coated.

80 grit - If 40 grit is rough enough to smoothen out your car's bare bodywork, 80 grit is a step below that in coarseness. This is a great starting point for after the filler's dried out, and you're looking to smoothen out the body filler before adding the primer, and then the base coat of the coloured paint on top

120-180 grit - Once again, these two are great for finer sanding of the filler layer. Some specialists finish off the filler with 120 grit after the 80 grit sandpaper has done most of the smoothening work of the overall surface. 180 grit can be used to carefully feather the edges of the filler and remove any spot putty, but also doubles as a good way to remove small scratches with minimal markings

320-400 grit - Both are excellent for the finishing steps of sanding and levelling the filler surface before the primer is painted on. Remember that even the tiniest of imperfections left on the filler can magnify greatly once the primer, and then the base-coat is added on top. Thus, these incremental grit sanding increases are needed

600-800 grit - Although some might be brave enough to use 400 grit sandpaper on the upper primer layer, it's best to use 600 grit for that job. Most would recommend starting with sanding the primer with 600 grit, before slowly moving up to the finer 800 grit paper

1,000-1,200 grit - Either one are good options for removing imperfections from the coloured base coat. The best way to do this is using a method called "wet sanding", where you would soak the sandpaper and the base-coat surface with a lot of water. The wet sanding process often enables the sandpaper to cut faster, and prevents particles of the paint from clogging up the abrasive paper. Although, and depending on how dry the paint is, a regular "dry sanding" would be good enough

1,500-3,000 grit - However, do know that even the finer 1,200 sandpaper will still leave marks, which you'll have to remove before adding the final clear-coat layer for the best results. For this, you can use 1,500 or up to 2,000 grit sandpaper. On top of that, 1,500 and 2,000 grit could also be used after the clear-coat has been applied, to get improved final eye candy. You can scale this all the way up to 3,000 grit, if you prefer. In both cases, wet sanding is the preferred way to go about it

Sanding Your Car's Paint

At this point, we're now well acquainted with which grit of sandpaper you'd need to use. In all, the varying grit sizing will be best suited based on what layer of the paint you're on, and what or how much is the material that you want to remove

Primer - Anything below or around 500 grit sandpaper will do wonders at quickly removing the upper paint surfaces, and down to the primer layer. This is great if you might want to start from scratch during the touch-up, or if some significant imperfections need to be ironed out. You can then move up to finer grit levels as you slowly start to finish off a smoothened look for the primer

Base-Coat - The argument of 'dry vs. wet' sanding will depend on your touch-up paint of choice. If it's waterborne, then wet sanding may start removing the paint itself. Once you've considered your approach, you can start using 1,000 grit sandpaper to sand out imperfections in the paint. You can then move upwards to 1,500 grit, as the base-coat surface starts looking finer and shinier

Clear-Coat - The final clear-coat layer is what tops off your car's paint, so you'll need to be careful about the grittiness of the sandpaper of your choice. 1,500 grit is a good starting point, though you'll need to be cautious about sanding it off too much. It's better if you have 2,000 grit, at least, as you can then move up and up to 2,500 grit, and the final 3,000 grit for an ultra-fine finishing touch.