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Hi,
Normally I sand between coats by hand and more recently a sanding block.
I'm talking about shellac and water base poly mostly, sometimes wipe on poly. Never lacquer or or brush on oil base poly.
Wondering if it is safe to use a ROS with 320 per 220 grit between coats, or should I just stay with hand sanding.
These are on larger projects of course like desks and tables.
Mike
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I use 400 or 600 grit between coats, by hand on a block. Anything coarser and it's too easy to sand through. The only time I use my ROS is on something heavier bodied, like Arm-R-Seal. I'll apply 3 or 4 brushed on coats and use the ROS with 325 grit before the last one or two coats to get a really flat and smooth surface. Then I apply one or two wiped on coats to finish.
John
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Works ok on rough stuff like shop shelves, etc but I find it difficult to keep from getting gouges, etc on fine work.
I've had better luck with "finish" sanders
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I use a Griot's 6" polisher and Griot's Garage Machine Polish 4–6 depending. Can be messy. Sand shellac @ 400 grit by hand with the grain.
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JR1 said:
I use a Griot's 6" polisher and Griot's Garage Machine Polish 4–6 depending. Can be messy. Sand shellac @ 400 grit by hand with the grain.
Against the fuzz, really. No sense pressing what you just set up back down.
Better to follow the leader than the pack. Less to step in.
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I know that automotive finishers use a pneumatic sander for 600, 1200, 2,400, 3,000 and 6,000 grit, I've seen it done on an automotive TV show. But they started at 600 grit and worked up in number.
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Simple answer from a hobby type that is not a finish expert by any means.. but recently experimented with this very technique on a varnish finish.
I recently sanded back a Waterlox finish.. two coats and then a sand back with 320 on a ROS. Two VERY light passes over the large flat areas only.
The results were good... BUT.... I would not use the ROS again. I would use my palm sander. I could see swirl marks in the "dust" left after sanding and I did not like that one bit. Was afraid those swirls were going to translate thru in the next wipe on coat of finish. Lucky for me that did not seem to occur.. but the scare was enough to push me off that idea again in the future. I will use the palm sander with 400 or higher going forward... or use the 320 and sand by hand with a block.
Just my two cents worth.
