When I make boxes, I usually run into this problem. The varnish seems to not want to stick to horizontal surfaces where they connect to adjacent verticals. I first thought it might be that poly doesn't want to stick to most things, but the attached photo shows an inside corner of a walnut box, using Pratt & Lambert 38 glossy as a wipe-on, diluted 2:1 with mineral spirits. This is the third coat, taking care to put plenty of varnish along the inside corners. It just seems to pull away from the edges as it sets up. Any help?
Thanks!
varnish.jpg