5” vs 6” Random Orbital Sanders
We aren’t going to be comparing specific sanders today but I want to go over some of the general differences between 5” and 6” random orbital sanders and how one or the other may serve you better.
Weight
The 5” sanders are typically light weight (less than 3 lbs or 1.5 kg - though this is a general rule and they can be heavier). With this lighter weight, controlling it one handed is easier than a larger sander, which is particularly useful when rounding over a corner or using it in non-horizontal situations. You will also fatigue less while supporting the sander on doorways or overhead sanding situations. The typical heavier weight of the 6” sanders helps them stay flat against a work surface better and tends to reduce vibration, which means less wear and tear on the tool as well as the user. Some of that weight comes from more powerful motors, which help sanders stay cooler and last longer.
Shape
Most of the lightweight 5” sanders typically have good ergonomics for one handed use, though some do have handles. 5” sanders are also generally less bulky so they can fit in tighter spaces. If you need to get in really tight spots a sander attachment to an oscillating multi tool is probably better.
DEWALT 20V Max XR Oscillating Multi-Tool: https://amzn.to/3Levnlq
Rockwell Oscillating Multi-Tool: https://amzn.to/3uzXAN3
Most 6” sanders will have a handle, as they are primarily used two handed. This two handed use helps hold the sander to the workpiece and reduces rocking. Most have pistol-grip handles and many have triggers to control start an stop as opposed to switches. The larger size can make it hard to fit into places, but makes prolonged use more comfortable.
Related to the shape is the actual size of the disk. If you are sanding on the inside of something like casework, the 6” disks will not be able to get as close to the corners as the 5” ones. Also if you are sanding narrower boards the dust collection of the 5” sander will work better than the 6” because the outside speed of the disk is not flinging sawdust as far or as fast.
Sanding Speed
The 6” sander has over 30% more area than a 5” sander, which means each pass is wider and you are able cover more surface quicker. Another thing that helps the 6” sanders is that they typically have larger motors, so more power, and that will also help increase sanding speed. This is different than the actual speed of the sander (although I always do recommend getting a sander with variable speed if you can afford it.) For me this is the biggest advantage of the 6”. I don’t love sanding and my powerful, larger 6” sander gets me done about 50% faster than my comparable 5”.
SANDPAPER
The 6” disks are more expensive than the 5”. However, despite being more expensive, because they cover more surface I haven’t found the cost per sanded area to be a lot more. I also sand more efficiently with the 6” sander, so for me each disk lasts a lot longer as well. The biggest downside to the 6” is they can be harder to find, whereas the 5” can be reliably found at all the big box stores. My favorite 5” sandpaper is the Mirka, and I like the Serious Grit for the 6”. Both are about 50 cents per disk, so for me the 6” is a better deal. (Let me know what your favorite brands of sandpaper for your random orbit sander are down in the comments. It’s sometimes hard to know what the best deals are and how well they work).
Mirka 5-Inch 8-Hole Sanding Discs: https://amzn.to/3NmhraV
Serious Grit 6-Inch 17-Hole Sandpaper: https://amzn.to/36UJ3U0
Cost
This is the big differentiator. Because they are made of more material, have more powerful motors, etc., 6” sanders are generally going to cost more. Sometimes a lot more. You can get a really nice 5” palm sander for under $100. When you want a good 6” sander, you are more likely looking at $100 - $300. There are the Bosche GET sanders and both the 5” and the 6” cost the same, despite the difference in size and motor power, so this price discrepancy it isn’t always a hard and fast rule.
My Recommendation
As always, the right tool is going to depend on the job at hand. If you do large projects or refinishing where you need to strip things down, then a powerful 6” sander is going to be awesome and save you a lot of time. If you do more smaller projects, or projects that require supporting the weight of your sander yourself (vertical or upside down sanding), or if you don’t want to spend as much money, I would get a 5” sander.
More generically, I would start with a lightweight 5” palm random orbital sander. I would get a nice one from any of the major manufactures, and consider features like dust collection, weight, battery vs corded, and ergonomics. I would be sure to get one with variable speed and no less than 2.5 amps. I love the dust collection on my Bosch ROS20VSC 5”, it is variable speed, and at under 3 lbs. it is very easy to handle. The motor is only 2.5 amps and the cord is a bit annoying, so this sander isn’t perfect, but I do like it.
If you have a 5” sander and are looking to upgrade, then I would suggest looking at the Bosch GET75-6N. This sander is 6”, has a 7.5 amp motor, the handles move and detach, it is variable speed, and the turbo mode is super powerful. I got this sander to do jobs I can’t manage with the drum sander and it works like a champ. This has replaced my belt sander since it is almost as fast on turbo mode and a lot safer to use. It is expensive though.
If you’re looking for something in the middle or only want one sander, I would look at the Makita BO5041 5". It is only about $10 more than the Bosch 5” and it has a trigger switch, handle, 3 amp motor, and variable speed. It is a little heavier than your average 5”, and the off hose dust collection isn’t as good, but it should feel better on larger flatter projects than a palm sander.
