Avoid swirl marks with my random orbit sander?
I will tell you exactly why and how to avoid swirl marks when sanding with a random orbit sander.
Scroll to the bottom for the TL;DR if you just want to get out of here and get back in the shop.
You’re sanding too fast, too random, and not working through grits of sand paper properly. I mean, they don’t make so many different grits just because it’s fun, they all serve a purpose.
Fortunately, it’s an easy fix. So put your sander down and read these tips on how to avoid the dreaded pig tails.
Please wear an n95 dust mask and proper hearing protection. If you have a shop-vac please hook that up to the sander. Not only will it give you better results, but it will save on cleanup and your lungs will thank you.
First step: Access your project and decide what grit to start with. Read the back of the sandpaper packaging for recommendations, but you will get a feel for this the more you sand. Removing stock on hickory may take 80 grit while poplar may take 120 or even 150 grit. You don't want to start too high i.e. 220 grit and have to sand 3x as long. Power tools are made for efficiency, use them to your advantage.
Second Step: Clean your surface. Any build up on your paper can leave marks while sanding. Your sandpaper also leaves grit behind on the surface, try to stay neat. Use a wire brush to remove paint buildup on the paper.
Now is when you need to slow down, take your time, and be patient. It is very important you do not skip grits. If you sand with 80 grit and move straight to 180, the 180 is too fine to remove the marks the 80 grit left behind, you will need to sand a really long time to remove them.
Move on to the next grit, start on one edge of the surface and gently guide the sander down the length of your surface going with the grain.
Don’t get crazy with the sander moving it back and forth. Don’t push down too hard on the sander. A firm grip is all that is needed, let the sander do the work. Guide the sander to the other end, do not force it and keep it flat.
When you reach the end, start back the other way, overlap your last path about 1/2 of your sanding disk. Think of it like mowing a lawn. You don’t start your mower and run around the yard
without any kind of pattern right? So, I have a table top that is 60″ long. I want to start on one edge and be down the table in about 40-50 seconds. If you’re a perfectionist like me, you will do this twice with each grit.
Step three: Rinse and repeat. Do not try to skip a grit just because you can’t see the swirls. They will haunt you as soon as you apply stain. Finally, I hand sand using a sanding block wrapped with 220 to remove any big rings the sander sometimes leaves. If you’re able to use a vacuum connected to your sander, do it. That will help keep your paper and surface a lot cleaner.
I should mention, I sand to 600 or even 2000 grit when I use an oil finish (which is always) and I highly recommend Odies Oil, best finish ever! More on that later, but it has replaced every single can of finish I had in my shop, which was a lot.
TL;DR Wear proper protection. Read package for recommended starting grit. Sand slow, about 1-2 seconds per inch. Do not skip grits. If you start with 100 grit then go 120, 150, 180, 220 and so on. Keep surface clean as you sand.
So, there it is. How to avoid swirl marks when sanding.
Follow these steps and you should end up with a professional looking finish you will not be ashamed to show off.
I’m always happy to share any tips or tricks I may have to save you a headache and a little time. I hope this guide clearly explains how to avoid swirl marks when sanding.
Need help with your project? Leave a comment with a guide you would like to see. I will do my best to provide you with the most informative information possible.