I am tracking experiments with different kinds of sealers, with different kinds of art or craft projects. I’m going to update this blog entry as I try different brands. My all-around favorite sealer and high gloss coating is Liquitex High Gloss Varnish. It is water-based, non toxic, and odor-free. It’s a bit pricey, but is reasonable if you buy it from Michael’s with a coupon.
Assume 3x coats of varnish unless otherwise specified.
Best for Acrylic-Painted Rocks:
Indoor/Outdoor: Liquitex High Gloss Varnish has lasted since 08/20/2017 on this tomato rock. The high gloss has dulled a little, but there is no damage to the paint on the top, bottom or sides. Paint is ordinary acrylic craft paint, and has held up extremely well.
Spar Varnish has lasted since January 2019 on this rock. No damage anywhere on the rock. The cracks in the paint were there before varnishing.
Not for Alcohol Ink:
Krylon Spray
Rustoleum Spray
Alcohol Ink is sensitive to any varnish with oil or chemical solvents, regardless of the media it is used on. Both Krylon and Rustoleum dissolved inks on ceramic tile. While the result was still pretty, and they held up well to use as coasters, many artists will not be happy with their creations melting in this manner.
Works for Alcohol Ink:
Aleene’s Acrylic Sealer Spray
Rustoleum Painter’s Touch Crystal Clear (Paint On).
While Aleene’s Acrylic Sealer Spray works very nicely for display-use items, it didn’t hold up to use as a coaster. Immediate “rings” were stamped into the surface.
Rustoleum Painter’s Touch Crystal Clear (Paint On) is still being tested for coasters, but has not immediately shown any sign of wear after a short test period. I will update in the future.