How to Avoid 5 Common Random Orbital Sander Mistakes Made by Beginners

A random orbital sander is one of the first serious power tools that a woodworker or restoration technician would purchase. Why? Well, the design is clean, it’s a simple tool to learn, and yet it’s the best option when you need to sand wood smooth in preparation for a final protective coating. But, random orbital sander mistakes are possible if you don’t have a full understanding of how this powerful tool functions.

In this article, we will take a closer look at five mistakes beginners make using a random orbital sander and how to avoid them.

What 5 Mistakes Beginners Make Using an Orbital Sander

Mistake #1:    Applying Too Much Pressure When Sanding

using a Random orbital Sander

Sanding is a laborious task, and it still takes time to get the smooth finish that you want when you’re using a random orbital sander. So, it’s natural to push down as you sand to speed up the process and move on to the next stage.

But this is the last thing that you should do because you will create uneven sanding and swirls on the surface. Pressing too hard can also overwork the sander, and it can generate a significant amount of heat. The sanding discs or sheets will wear out quickly, and the sander can shut off unexpectedly.

The Solution to Applying Too Much Pressure When Sanding

Resist the urge to press down on the orbital sander as you work, and let gravity do the work for you. The abrasives that you choose will do the hard work. If you need more aggressive sanding, simply switch to a coarser grit sandpaper or sanding disc. The proper action for a sander is a smooth gliding action across the surfaces.

Mistake #2:    Sanding Too Slowly or Too Quickly

Another common mistake is moving the sander across the work-piece too quickly to complete the sanding task faster. But, this is an easy way to miss areas that need more attention, and the finish is likely to be poor. Sanding too slowly is also a problem because it’s easy to over-sand or cut through areas, which damages the surface.

The Solution for Sanding Too Slowly or Too Quickly

Moving at a steady and controlled pace is the best way to get superior sanding results. This is hard to quantify, but as you gain experience with sanders, you will find the right balance of speed and sanding performance.

Mistake #3:    Using Too High or Low PSI or RPMs Settings When Sanding Wood

When you use a pneumatic or electric sander, it’s important to set the correct sanding speed for the application. This is essential if you want to get a high-quality finish that’s ready for a final protective coat. Setting the correct speeds will help you to avoid creating sanding swirls on the surface which take time to remove.

The Solution to Using Too High or Low PSI or RPMs Settings When Sanding Wood

An electric sander has a speed setting that allows the user to change the RPMs at any time. There are various advantages to using certain speeds for specific applications. A full RPM range list for common woodworking applications is beyond the scope of this article. But, the 10,000 RPM range is suitable for most applications unless you need finer control for certain surfaces.

If you’re using a pneumatic sander, you need sufficient air pressure, and the power tool must be lubricated. The optimal air pressure is 90 PSI, and daily oiling is highly recommended if the sander is in constant use. A pneumatic sander has a speed controller to fine-tune the speed to avoid swirls when sanding faster.

Mistake #4:    Starting in the Air and Stopping on the Work Surface

One of the more common random orbital sander mistakes is starting the sander in the air and then stopping it on the work-piece. This creates hesitation when the sander is placed on the surface leading to swirl marks and uneven sanding. Trying to place a sander that’s already running on the surface is difficult and unnecessary.

The Solution for Starting in the Air and Stopping on the Work Surface

Always start the sander when it’s in position on the work piece, and it’s easier to control the tool. When you’re ready to stop, simply lift the sander off the surface and stop it in the air. A simple way to remember this is “Start on and stop off”.

Random Orbital Sander Mistakes

Mistake #5:    Sanding on an Angle

One of the more common mistakes beginners make using a random orbital sander is trying to use the tool as an angle grinder. They try to sand out a mistake on an angle, but this doesn’t work, and it tends to create more uneven surfaces.

The sanding discs and sheets are quickly destroyed, and the backup pad may need an earlier-than-expected replacement.

The Solution for Sanding on an Angle

A hook and loop pad saver or a foam interface pad using conventional abrasive sanding discs or sandpaper can be used to finish curved or complex profiles on flat surfaces. An irregular surface may require a coarser grit, and moving through the entire grit sequence may be needed. It may be necessary to fill in defects with a filler and then evenly sand the surface again.

How To Prevent Random Orbital Sander Mistakes From Happening

There are six easy ways to avoid random orbital sander mistakes:

1.    Take Your Time When using a Random orbital Sander

A random orbital sander is designed for slow and steady sanding without lingering in one place for too long. The optimal speed for most applications is around 12 seconds per linear foot of sanding, which is about 1” per second for easy reference.

At first, this may seem like a slow and tedious experience, but this time is necessary for the random orbit sanding oscillations to do their job. When you take your time, you can avoid the creation of swirl patterns and create a smooth surface at the same time.

2.    Don’t Press Down When Using an Orbital Sander

A sander requires no pressure to sand at optimal efficiency, and it’s important to let the tool work as intended. Adding extra weight creates more problems, you will slow down the sanding process, and you can even damage the motor.

If you need more aggressive sanding, switch to a coarser grit and avoid the urge to press down.

3.    Clear the Dust

The headlight lens should be wiped frequently to cut down on the dust that’s circulating in the air. A significant layer of dust can accumulate between the lens and the sanding disc quickly. Removing this dust will improve the sanding disc grit contact, which improves the sanding speed and performance.

4.    Don’t Tilt an Orbital Sander

If you see a scratch or rough spot on an angle, it’s tempting to use the random orbital sander to bear down on it and smooth it out quickly. But, an orbital sander is designed to be used on flat surfaces, and hand sanding is a better way to fix these problems.

5.    Vary the Sanding Grits

Every progression in sandpaper grits is designed to remove a scratch that was created on the previous sanding pass. So, you can’t expect to fit a super fine sanding grit disc on your random orbital sander and get a super smooth finish.

It’s important to start with a coarser grit and work through them progressively to get the best finish for a final protective coat.

6.    Replace the Sanding Discs as Required

If the sanding disc stops cutting and it’s clogged with dust, it is time to remove it and replace it with a fresh disc. When a sanding disc is not working as intended, you will notice that the sanding times are longer and the sanding results are poor.

As you gain experience with a random orbital sander, it will become obvious when you need to change a sanding disc.

How to Fix Any Random Orbital Sander Mistakes

When you make a mistake, the best option is to switch to a coarser grit, re-sand the surface to remove the depression, and then move back to a smoother grit. The problem can be corrected with a sanding block wrapped with sandpaper if you don’t want to change the sanding disc.

Apply even pressure to the surface and move the sanding block evenly across the surface to make it smooth. This is a common problem with belt sanders that can create gouges if they are not kept under tight control at all times.

Avoid pressing down when sanding; you can remove a lot of material with no added pressure and a coarse grit sanding disc of sandpaper. To remove deep gouges, it may be necessary to plane the surface and return to sanding later when the surface is even.

Conclusion -Random Orbital Sander Mistakes

As you can see, it’s easy to make random orbital sander mistakes as a beginner or more experienced user. But, if you follow the tips and advice in this article and use high-quality abrasives, you can avoid many of these problems.

Using a random orbital sander should be a smooth and steady process. It’s important to work through the sandpaper grits to get a superior smooth surface for the final protective coat.