How to Varnish Decoupage. Varnish is used to make cutout items look as though they were hand-painted onto a surface. It is a long process that requires a lot of patience.
Dip the brush into the varnish and wipe off the excess varnish.
Begin covering cutouts with varnish at the center of the surface and brush outwards.
Check to make sure there are no bubbles or drips and that the surface is smooth.
Allow to dry overnight.
Repeat 18-20 times for best results.
Use a high-quality brush that won't lose its hairs. Varnish works best when it is thin. Keep it thin by adding a small amount of paint thinner. Clean brushes with paint thinner. Seal the varnish can every night to prevent varnish from thickening. Cover with plastic wrap before sealing the lid for extra protection. Set the brush down flat; standing it on its bristles will ruin it.
Always work in a well-ventilated area to avoid fumes.