Hello to all, I have a large A-frame (4 shelves) bookshelf made from pallet timber. I use it for plants. It has deteriorated from the sun, water and is cracking. I would like to put marine varnish on it to spruce it up and protect it from the sun and water. Which sanding machine would do the job and what grit etc? I would like to use the machine on the scratches on my car also. Thanks,