http://www.jamestowndistributors.com/userportal/show_product.do?pid=2155&familyName=Preval+Spray+Gun+Kit

+ the correct amount of reducer in the varnish to make the varnish 'flow' but not sag.

Then you have less 'finishing' work after the varnish cures .... no flat sanding & hand-rubbing/polishing/buffing.