- I’ve been experimenting with painting for some time and never quite happy with the results. Finally allowed as how I am a sculptor, maybe I need a sculpted surface to paint on, rather than expending enormous amounts of effort trying to make a flat surface look carved. So I tested a number of ways of building three-dimensional Celtic knot that would support paint and not weigh down a canvas too awfully much. There’s a lot more fun to be had painting knots if it doesn’t take six hours to carve them first, and they hang better if they’re not solid wood.
I’ve tried making knots from the balloons used to make animal sculptures and covering them with papier mache. It works, but it takes a long time and a lot of expensive products. It would be easier if the balloons were filled with something rigid–they wouldn’t need as much reinforcement from the covering layer. (Balloons will hold their air for a long time if the balloon is sealed, as it is somewhat by papier mache, but the seal isn’t perfect and it won’t last for as long as I want the painting to last.) Urethane foam-in insulation came to mind. The product comes in a pressurized can with a long straw that could be inserted into a balloon and pumped into a balloon.
My theory is sound. However, the practice needs work. It turns out that the insulation product generates a tremendous amount of gas in the process of forming the bubbles that make the insulation; that gas rushes to the end of the balloon and fills it up long before the balloon fills up with foam. (In a more normal application, this gas would simply blow off into the atmosphere. The gas has a strong odor of acetone.) The first two attempts were mildly successful–I got some foam into the balloon and was able to mash it along the length of the balloon and bleed off some of the gas. In order to make the shape I wanted, however, I did need more foam in the balloon.
The third try proved the limits of the experiment. I didn’t stop the foam quite fast enough, and the balloon exploded. If you’ve ever wondered how the bomb experts on CSI (or in reality!) do their job, I might recommend this experiment. I was covered in urethane foam, as was my work area; there’s a neat void behind me where I absorbed the impact, such that it was, and clearly demarcated lines of bubbles where my sweatshirt wasn’t. Fortunately for the work-in-progress around me, urethane foam blown through the air loses a lot of its stickiness and lifted off fairly easily once it cured.
The sweatshirt is ruined. I’m saving the pants for subsequent work with foam. I (and my neighbor) are grateful that her 10-year old son was not around to see this. We hope that he doesn’t get too curious about how I’ve prepared these canvases.
I may try this again–I’d like to make permanent balloon sculptures. I will definitely need the assistance of another person. It’s possible that if we prick the balloon at the far end and temporarily seal it by twisting that end, we can bleed off the gas and allow the foam to fill more of the balloon. It’s dicey, and there is still the variable of how much the foam will expand.
Latex insulation doesn’t expand enough to be any fun at all, and so the ease-of-clean-up is completely offset by the uselessness of that product for my purposes.