ROS - How aggressive??

[Mike B]

Hi

This may be a little like "how long is a piece of string" but can anyone give me an indication of the difference in "aggressiveness" of a 5" ROS compared to a 6" ROS??

So far, the only comments I've seen are regarding the surface area of the pads and associated speed to sand a given surface area e.g. a table top.

I'm assuming that the 5" will be less aggressive due to its smaller radius meaning that the edges will move less quickly than on a 6" model. Also, most 5" ROS that I've looked at appear to have a 2 or 2.5mm orbit compared to the 6" versions that have 3 or 6mm orbits...

I notice most of the American magazine articles show 5" versions in use - is this because they are better for fine finishing??

Basically, I have some house doors to sand and am thinking that a 5" ROS would be best as the rails and stiles are about 4" wide and this may be too narrow for a 6" ROS - but as about half are painted will a 5" ROS be aggressive enough to shift this??

Cheers
Mike

 

[ike]

Do you mean 'aggressiveness' in terms of stock removal or holding onto it?.

For stock removal, bigger orbit = faster sanding, smaller orbit = finer finish, regardless of the pad diameter.

Bigger pad diameter will make it more forceful controlling the direction, but so too will a bigger orbit. A 6" sander has roughly 30% more sanding area, hence 30% more reaction force required of your muscles (+ the extra weight of the machine).

Ike

 

[Mike B]

Ooops!

I meant in terms of stock removal...

 

[Scrit]

I'm with Ike - the disc size has nothing to do with aggressiveness, it's the orbit size which dictates that. The bigger the disc the faster the machine can cover a given area. Another factor is how well braked the disc is (i.e. how limited the tendency is for the disc to spin freely) - personally I've found Festool to be the best. To avoid dubbing over get a machine from a manufacturer who can supply a "hard" backing pad - softer pads are more likely to dub the edges. One thing - you'll still need to get into the corners either by hand or with something like a Fein Multimaster

Scrit

 

[ike]

Mike,
For stock removal as described, you need, like a 5mm orbit. Unless you already have a finishing sander, how about a dual orbit machine to give you the best of both?, to finish sand the doors as well.

Ike

 

[Jake]

Stuff like removing paint is where the Rotex comes into its own, if you have the cash.