Knowing how to sand metal is an extremely helpful skill in a variety of situations. You may need to remove some old paint from it, even out parts of the surface that are scratched or prepare the metal for painting or other treatments that need a proper preparation.
A thorough sanding session will result in an even, smooth surface on the entire length of the metal and leave it ready for whatever comes next – from a high-polish to paint and more.
Without further ado, let’s take a look at how to sand metal properly!
How to Sand Metal Like a Pro
Follow these instructions closely and you’ll quickly learn how to sand metal like a true expert and achieve excellent results.
The most common tools for sanding are the excellent random orbital sanders or the classic sanding blocks. Orbital sanders do the hard work very quickly, easily and also provide absolutely outstanding results, especially if you are evening out large ridges or extensive surfaces. They’re quite affordable, as you’ll see by following the link above, and last a lifetime of use so they’re definitely worth the entry price.
The sanding blocks are also effective but you’ll need a whole lot more physical effort and time to complete a large surface than you would with an orbital sander. It’s also harder to guarantee a clean, smooth, scratch-free result. Remember that if you want to remove huge chunks of material, you are better off grinding before sanding.
How to Sand Metal Using an Orbital Sander
When sanding metal with an orbital machine, always start with a coarse sanding disk. An 80-grit sanding disk is quite coarse and easily removes all the top layers of the paint, rust or scratches. However, always remember to be careful and sand slowly to avoid eating into the surface and weakening the material. As soon as the top layers of old paint or material are gone, switch up to a higher, finer grit.
Consider finishing off the sanding with a 200-grit sanding disk. The disk is smoother and will not eat into the metal surface, allowing you to give the metal a good sanding until all the material is gone and the surface is nice and clean. If there are tight spaces where rust, ridges or paint remains, use a sandpaper sheet manually to reach out into these areas. In the same fashion, start with 80-grit sandpaper before going to a smoother one.
Your metal should feel and look smooth. However, if you would like to have a smoother finish, you can also consider using a ball of steel wool to give it a unique, beautiful finish. Simply rub it on your metal in circles until the metal looks polished.
Using a Sanding Paper
If you want to do this manually, the process is similar but much more extensive. Just like you would do with an orbital sander, start with the coarse sandpaper – 80-grit sandpaper will do. The best way to sand is along the grain of your metal (if any is present) else you can always do it in circular motions. When you have removed much of the unwanted material, switch to 200-grit sandpaper to finish off the sanding process. Use pieces of either sandpaper to remove pockets of the material that might have been left in the tight spaces. Finally, you can finish off with steel wool if you want a smoother finish.
Things to Keep in Mind When Sanding Metal
Purchase the Right Type of Sand Paper
Your sandpaper will determine how efficient you will be at your work. Different types of sandpaper also come with varying levels of coarseness. If you are looking for a sanding surface made of natural materials, emery works well with both the hands and power sanding. As for human-made abrasives, you may go for aluminium oxide, silicon carbide or Zirconia alumina, which is the best of the three as it lasts longer and maintains sharp edges all through the process.
Know the Grit Numbers
Grit numbers between 36 and 100 are best used for removing large chunks of materials and great for power sanders as it turns them into material-eating machines (just remember to work slowly and carefully as they act quick). The numbers between 100 and 180 are suitable for smoothing workpieces and the higher grit numbers between 180 and 320 give your surface a high-polish, scratch-free finish. The sandpaper gets smoother as you go up and you can even get it in 2000 grit or more, which are used to achieve those mirror-like finishes you often see.
Wet Sanding Gives a Good Finish if Done Before Painting
If you plan to paint your metal surface after sanding, consider one final bluff with wet sandpaper before painting especially if it is a vehicle surface. Consider using sandpaper with grit numbers that are higher than 400 for this work.
You can also give the painted surface a little sanding with sandpaper with a high grit number. Something between 1,000 and 2,000 grit will work perfectly as it helps in removing small imperfections in the top layer of the paint. If the finish looks dull after sanding, use a high-speed buffer to give it a quick shine.
Also, always consider treating metal surfaces such as iron and steel if you are to use them outdoors after sanding to further protect them from the elements.
Quality sanding gives a new life to your metal surfaces and knowing how to sand metal is not only useful for DIY renovations but also a crucial skill in many jobs and professions. Use the guide above to learn how to sand metal correctly and ensure that you always achieve great results!
Thanks as always for reading and I’ll see you on the next one.