For the past few years, I have been quietly working on my own “scientific” tests to figure out the best paints and coatings for outdoor craft projects, like painted rocks, stepping stones and planters. The results have been quite disappointing so far, and some formulas are still under review.
Dimensional Magic by Modge Podge and Liquitex High Gloss Varnish on Plasterite Faux Rock
Result: Fails within 2 years
This rock was painted on January 16, 2018, and left outside on my front porch. There is considerable damage, both back and front, that I noticed well before the first year had passed. There are pock marks into the plasterite, which is showing signs of disintegration. The Dimensional Magic product was applied to the white center dot to bring it up, and you can see it is lifting off from the stone. There are also signs of what looks like rust, though I can’t imagine where it comes from.
Conclusion: This combination can work for indoor stones. Both products are my favorites for jewelry and indoor decor, but the combination is not an effective long-term treatment to protect an outdoor project.