: Hi,
: Can anyone explain what is the difference between wet sanding versus dry
: sanding.
: Obviously, wet sanding does not produce the fine particle dust, but what
: else?
: In what situations one should do wet sanding compared to dry sanding?
: Leszek

You really should never dry sand varnish it leaves scratches in the surface that the next coat won't completely fill.

Good technique to wet sand is use a sponge backing pad on the sandpaper so you have no hard edges, wet with either a lint free rag or a large sponge and have a rubber squeegie to remove the water/sanding residue to see where you need further sanding. 220 wet/dry paper to start and nothing finer than 320 for final coats.

I like sanding epoxy the same way, easier to see if the surface is smooth this way and you again don't create gouges that are hard to fix.

Bill H.