How To Avoid Swirl Marks When Sanding With Random Orbit.
Why do I get 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.
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 swirl marks when sanding.
First step: I use 80 grit to strip paint or varnish and stain. Don’t be afraid to get aggressive in this step.
As long as you don’t dig a hole in your surface, you will be fine. Make sure you remove all of the old finish before moving on.
Second Step: Clean your surface. Any build up on your paper can leave marks while sanding. So, try to stay neat.
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.
We are going to use 100 grit now (you can even jump to 120 grit here). Start on one edge of the surface and gently guide the sander down the length of your surface going with the grain.
Do not 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. Guide the sander to the other end, do not force it.
When you reach the end, start back the other way, overlap your last path about 1/4 of your sanding disk. Think of it like mowing a lawn. You don’t start your mower and run around the yard
with no 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. Here is the grits I recommend. 80, 120, 150, 180, 220. 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.
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 never have to check for swirl marks by wiping the surface with mineral spirits. I follow these tips and apply my stain. It comes out perfect every time. If you choose to test your surface, never use water it will raise the grain. If you do use water make sure you do a final sanding with 220 to knock down that raised grain.
I am 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.
TL;DR: You’re probably going too fast and skipping grits, DON’T skip grits. You’ll want to move the sander about 1 or 2 inches per second. Let the sander do the work, don’t press down too hard. Keep your surface clean.
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.