Bertotti said:
I seem to read how fast the ro150 is compared to the ro125. I can't help but imagine it will be incredibly fast compared to my ro90! One thing for certain is the 90 is doing a far better job than my belt sander did. It would just fill up with floor poly so fast I was always changing belts. The p40 on the ro90 seems to last a fair amount of time and if I use an eraser on the paper now and then, even longer. Oddly it seems to stop working well but doesn't feel all that smooth. I still pull it off once it seems to not work properly. I set it aside for some smaller project I can work on in a better potion.
I assume that you're aware that there's 36, 24 & even 16 G belts available? A belt sander should, even with the most aggressive grits, be infinitely smoother running & more easily handled than that nasty little RO90 in ROTary mode. Maybe you're different, but in my hands the "90" was unruly, prone to bunny-hopping on an almost constant basis & required an almost death-grip with both hands to prevent undue workpiece damage. In my opinion the RO90 is one of the poorest sanders to have come from the Festo works: it seemingly cannot handle any single task that isn't significantly done better elsewhere. A DX93E Deltex is a far better Delta, Metabo's SXE400s or Mirka's DEROS 77/2.5 or 5.0 mm are superior small Randos, & the RO150 a far superior (probably the best) ROTary. Even if classified as an allrounder "3 or 4-in-one" the RO90 is still a miserable failure, incapable of performing any particular task satisfactorily.
My principle concern with the RO90 is I suspect down to severely compromised ergonomics. I too have wrist problems & consequently found that the "extreme" grip required to keep the littlest Rotex on the straight & narrow to be extremely tiring. The much larger platen size of 150mm allows a lighter touch to be used. It's just far less prone to gouging, digging-in & hopping.
Having re-read your original post (Alanbach) I think that you'd be almost clinically certifiable to use the littlest Rotex on flooring!
In comparison, both the RO 150 & the various belt sanders I've owned & used (Makita, Hitachi, Bosch, Metabo & Festo/HolzHer) were faster, smoother yet more aggressive & paradoxically (particularly the latter 2 belt sanders when fitted with sanding frames) also extremely gentle if & when required too. A framed belt sander is also possibly the best tool of all for flattening stepped glue-ups & fresh floorboards when used as recommended across the diagonals & subsequently along the grain.
Belt sanders in my experience actually benefit from having substantial size & mass. Instead of requiring a firm grip, just a light restraining grip on the rear handle to counteract their "pull" is all that's really required, with perhaps just a lightly rested hand on top for slight extra pressure or steering input is necessary. Their weight does the rest.
As an aside, if you apply a piece of old poly plumbing pipe to the front roller of your belt sander (a couple of seconds back & forth is all that's required) regularly whilst still in motion it will assist greatly in preventing belt loading & swarf buildup.
I've done quite a few floors in my time, both newly-laid boards & parquet, & refinishing old ones. If commercial hire floor sanders are "out" then a 4" x 24" belt sander would be my second choice with a succession of 24 & 36 grit across the diagonals with 36, (maybe 60), 80 & 120 G along the grain. Using a 150 Rotex is also possible, but will probably be slower overall due to the overall smaller platen size.
Otherwise, an 150 x 8 mm Mirka DEROS with Ceramic mesh (Abranet Ace HD) in 40, 60, 80 & 120 G increments would actually be kinder to your wrists & about as fast (with 60% greater eccentricity but random as opposed to gear-driven rotation) as a big heavy Rotex. Approx 60% weight saving & far longer abrasive life, assuming you aren't trying to sand nailheads, etc. As a long-term Carpal Tunnel Syndrome & arthritis sufferer I personally find the Mirkas to be the gentlest sanders of all for my ageing bones, tendons & nerves.
