If you keep putting weight on it, most probably will end up wearing the sander mechanism. The weight of the sander should do the job, provided you are not using the sandpaper disks for too long and have already worn down the abrasive... With geared ROS sanders with more then say, 600 watt motors and larger than 1/8" or 3mm orbit size, the sanding power will make large jobs quite faster than with a lesser, common sized sander, like those from DeWalt, Milwaukee, Ryobi, or std Bosch 5" ones. To give you an idea, I sanded the Mahogany top of a large 8-person dinning table; with my old Bosch PEX12 AE (125mm disk, 380 watt, 3mm orbit size), it took me about three to four full hours to go from rough to almost polished wood surface, ready for finish... With my new Makita BO6050 (150mm disk, 792 watt, 5.6mm orbit size and geared, forced rotation) it took about 40%... that is a 60% time and effort savings. And, of course, it went much faster through sanding disks than the old and much milder Bosch!
