Thread: Orbital Sander Vs Random Orbital Sander

The short answer is that the more aggressive random orbital is better at rapid stock removal and the gentler orbital only is better at fine finish sanding. However, both types have their pros and cons. With the random orbital sander both oscillating and spinning, it removes more material in a shorter time and leaves less obvious sanding marks than an orbital only sander. The down side is that a random orbital sanders more aggressive action requires care when sanding the edges of flat surfaces such as table tops etc. It will happily leave dips and valleys given the chance. This is why Festo have RO sanders with both 5mm and 3mm actions. The larger action being good for aggressive stock removal and the smaller one better at fine finish sanding. The other down side with RO is that you are limited to fewer grit size options and extra expense of hook and loop sanding disks.
An orbital only sander is much more gentle in the table top scenario, so you don't have to worry so much when sanding close to the edges, but they tend to leave more obvious orbital scratches in the surface, requiring finer grades of paper. It will also take hours to remove the same amount of material that an RO would do in minutes.The upside is that you can use the wider grit variety and cheaper cost of sheet sand paper.
In an ideal world, you'd own both types, but if you had to have just one, I'd say get the random orbital.

Originally Posted by tcowdroy

The other down side with RO is that you are limited to fewer grit size options and extra expense of hook and loop sanding disks.

With all due respect, methinks you're not shopping in the right place for disks. While I can't argue with you about the price being a bit higher, there are velcro disks available in grits from 40-2000. That being said, disks finer than about 320 probably need to be bought from automotive paint suppliers as they're pretty much useless on timber. Also, many orbitals now come with velcro options as well.

Originally Posted by tcowdroy

The down side is that a random orbital sanders more aggressive action requires care when sanding the edges of flat surfaces such as table tops etc. It will happily leave dips and valleys given the chance. This is why Festo have RO sanders with both 5mm and 3mm actions.

It's not only the 3/5mm action that causes the dips, a soft or hard pad has a lot to do with it as well. I've been using a 5mm action Festool at work for 3 years with a hard pad and this clears the problem right up. The 3mm actions at school have the soft pad and are horrible for dips and round edges over before you can stop it.

I'll second the use of a hard pad on the Festool, soft timbers allow the sander to create waves, but with a hard pad this is greatly reduced.

Thanks for the comprehensive answers.
I have an orbital sander, now I need to get a ROS.

Cheers
John

Originally Posted by tcowdroy

The short answer is that the more aggressive random orbital is better at rapid stock removal and the gentler orbital only is better at fine finish sanding. However, both types have their pros and cons. With the random orbital sander both oscillating and spinning, it removes more material in a shorter time and leaves less obvious sanding marks than an orbital only sander. The down side is that a random orbital sanders more aggressive action requires care when sanding the edges of flat surfaces such as table tops etc. It will happily leave dips and valleys given the chance. This is why Festo have RO sanders with both 5mm and 3mm actions. The larger action being good for aggressive stock removal and the smaller one better at fine finish sanding. The other down side with RO is that you are limited to fewer grit size options and extra expense of hook and loop sanding disks.
An orbital only sander is much more gentle in the table top scenario, so you don't have to worry so much when sanding close to the edges, but they tend to leave more obvious orbital scratches in the surface, requiring finer grades of paper. It will also take hours to remove the same amount of material that an RO would do in minutes.The upside is that you can use the wider grit variety and cheaper cost of sheet sand paper.
In an ideal world, you'd own both types, but if you had to have just one, I'd say get the random orbital.

Thanks for these great explanation, I'm glad that I'm on the right track

Picked up a brand new triton TROS on ebay for $77 + $15 postage.
So I'm set to go!

Originally Posted by elanjacobs

With all due respect, methinks you're not shopping in the right place for disks. While I can't argue with you about the price being a bit higher, there are velcro disks available in grits from 40-2000. That being said, disks finer than about 320 probably need to be bought from automotive paint suppliers as they're pretty much useless on timber. Also, many orbitals now come with velcro options as well.

You can buy Festool 6" ROS pads up to 4000g at Total Tools in Sth. Melbourne, Just Tool in Thomastown and Power Tool Specialists in Carlton, just to name a few. I also have to say that I routinely sand oil saturated timber through to 4000g and the difference in finish as opposed to say 400g or even 1200g is significantly noticeable.

Rob