Revarnishing kitchen cabinets, using polyurethane (oil base) over existing varnish. Can I use liquid sandpaper to degloss the old varnish? What about in between coats of the new? Thanks!
Yes, after sanding you can use the liquid deglosser for a final wipe down and cleaning prior to applying fresh coats of varnish. Using it alone in lieu of sanding is not a good idea IMO.
Do not use it between coats, just give a real quick fine sanding (or steel wool) and wipe down with a damp cloth or tack cloth.
Use outdoors or with good ventilation as that stuff is a volatile solvent.