I receive a lot of emails by folks who would like to put their paper mache sculptures outside. Can paper mache be waterproofed?
I’ve always said “no,” but I never actually tried it myself. Therefore, I decided that I needed to do some experiments to see if there really is a way to weatherproof paper.
I was delighted when I discovered that Jackie Hall, writing for the Papier Mache Resource website, beat me to it. Jackie tried just about every finishing material that she could think of, and carefully documented her results.
In the end, she discovered that you really can waterproof paper mache sculptures, using yacht varnish. This product may be sold as marine varnish at your local paint store.
Now that I know you really can keep the weather from ruining a paper mache sculpture, I’ve got to try it mysel. When I do make an outside sculpture, I’ll do a few things differently during the building process. These things may not be necessary, but they do seem reasonable:
- I would use a high-quality carpenter’s glue to stick the paper onto the sculpture, instead of using the usual flour-and-water paste. I would do this because flour is one of the favorite foods of fungi (yeast is a fungus, and you know what happens when you add yeast to bread dough). Flour is also a favorite food for animals, like mice, raccoons, and golden retrievers. The varnish might mask the odor of the flour, but I would play it safe and use the glue instead.
- I would keep the bottom of the sculpture far enough above the ground to prevent splashback from rain or sprinklers from covering the sculpture with a thin film of mud. Soil microbes, especially fungi, are incredibly strong, and could eat their way into the sculpture and cause it to rot. Some fungi is strong enough to work it’s way into concrete and even rocks, so a paper mache sculpture would be a piece of cake for them. To prevent the bottom from getting wet, the sculpture could be placed on top of a rounded rock that allows water to drain away. I don’t know exactly how a larger sculpture (a hippo, for instance) would be protected, but there must be a way to do it.
- As Jackie suggested, I would re-apply the marine varnish at least once a year.
- I would make sure the sculpture is heavy enough to keep the wind from blowing it away.
If you have ever made a papier mache garden sculpture, please let us know what happened to it. Did it survive out in the weather? Did the paint colors fade in the sun? I would really like to know, because I’m running out of room in my house for all the critters I’ve been building, and I’d love to fill my garden with some weird and wonderful animal sculptures.