Your going to be doing this for DAYS with a little orbital.. Go buy a cheap 1/2 sheet or belt sander for 50 bucks. The half sheets are nice since you only buy the basic paper both orbital and belt need a special paper to fit. Plus with a larger working area you'll get a flatter surface overall you may get dips and curves with the little orbit and you will probably need dozens of disk and at .80-1.00 a pop you could have bought the belt sander and paper to do the job.. This is if the sander last through the job you may burn it up since it was never made for these large projects..

I need to purchase an orbital sander to sand my 200 square foot cedar deck. I power washed it and now the wood fibers are raised on the top of the decking. How many 60 grit power sander discs will be needed and how many 100 grit discs will be needed? Any ideas, tips, advice is welcome.