I'm finishing a rather large slab and just put on the first coat of semi-gloss poly. Minwax says to lightly sand with 320 between first and second coat. Can I use my ROS for this or do I need to find my sanding block?
You can use your ROS, but you might find it gums up the paper rather
fast if it's not been curing for a week or more.
I would use wet dry 320 with a drop of dish detergent, which keeps the
paper from loading up.
Mind you I don't do poly very often.. (RARE), but that has been my
experience. I use a block with a cork , you can also use felt rather
The wet dry will give you quicker cut, less loading, a finer scratch
pattern, and a lube to make it easier. My results were much better.
Also you control sand through much easier, but with poly the build is
pretty thick and unlikely to sand through except on a sharp corner.
Also note that there are two reasons for sanding...
1. To smooth and remove imperfections, dust nibs, etc. Unless it is a
real mess and IME, no need to do so until just before the last coat, if
2. To roughen slightly giving the new coat something to grab onto. No
need for that if you apply additional coats within 4-8 hours, the time may
vary with different brands. I regularly apply four coats - sans sanding -
in a day.
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