Sanders - random orbital vs orbital

Here comes another newbie question (or several actually)...

What's the difference between an orbital sander and a random orbital? Presumably, the random orbital has a different sort of movement, hence the "random". But is there a clear difference in the applications that each are suited to?

Same question for 1/3 sheet and 1/4 sheet orbitals? Is it just a matter of 1/4 sheet being smaller & easier to handle?

Which all leads to... If you had only one power sander, what type & size would it be?

jonathan

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Originally Posted by planetjag

What's the difference between an orbital sander and a random orbital?

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Orbital just vibrates or rotates in small continuous circles in one direction. Random orbital rotates in small continuous circles in one direction as well as the whole head of the sander rotating in a semi-random fashion. If you hold the Orbital sanders steady on a surface they can leave little circular swirls or marks. A random orbital is less liker to do this since it's orientation continually varies relative to the surface.

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Originally Posted by planetjag

Presumably, the random orbital has a different sort of movement, hence the "random". But is there a clear difference in the applications that each are suited to?

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Random orbitals are normally circular in shape so cannot get into corners like a square or pointed sander like the B&D mouse can. Both are useful in their own way.

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Originally Posted by planetjag

Same question for 1/3 sheet and 1/4 sheet orbitals? Is it just a matter of 1/4 sheet being smaller & easier to handle?

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Smaller sander for smaller work.

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Originally Posted by planetjag

Which all leads to... If you had only one power sander, what type & size would it be?

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I like to get my things as smooth as possible with hand tools and then hand sand for finish. Random orbitals are very good for finishing big surfaces eg the 320 grit between coats sanding.

I think you mean "finishing" rather than power sander? If I could only have one power sander I wouldn't be without my big Makita belt sander. They really are impressive tools. I use mine for all manner of things, including shaping wood and metal, apart from final finishing.

Quote:

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Originally Posted by planetjag

Which all leads to... If you had only one power sander, what type & size would it be?

jonathan

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You've already got a good explanation of the diffs, but if I could only own one I would decide based on the kinds of jobs I was likely to be doing. For bigger jobs, a dual-mode ROS would be my choice. If I made mostly small items, a smaller ROS with a short throw to give a nice finish quickly. Need to sand in corners a lot? A detail sander works well there, or a 1/4 sheet orbital. Odd shapes? A profile sander is the go. So like most things, it's horses for courses.

At the end of the day, one sander can't really solve all your challenges. That's why I ended up with 4 or 5 different kinds. :-

Thanks for the responses, and BobL you're right, my final question should have read "what type of finishing sander". I can't see myself having much use for a belt sander at the moment and I have access to a loaner only 15 minutes drive away when I do need it. There's also a 1/3 sheet there too. Both Makita.

Given a tight budget (which after some research pretty much rules out a ROS) and the presence of the Makitas I can borrow if I plan ahead, I might just get a 1/4 sheet or detail sander so that I've got something close to hand for the little jobs that don't warrant a 1/2 hour round trip.

So the next question becomes ... as far as I can see there's not a whole heap of difference between a 1/4 sheet or a detail. The overall size of the pad is not greatly different. The detail gets into corners, but you're committed to buying the right shaped velcro sheets. I didn't think to check if the 1/4 sheet ones have clips to take regular sandpaper. As I'm writing this I have just realised that the 1/4 sheets might be more powerful too.

This tool acquisition process just creates dilemma after dilemma!

jonathan