I'm doing an involved project with my 7/8th graders. Moyo's 'Soliloquy: Life's Fragile Friction' is the subject. He paints on canvas with acrylics and carves designs into the paint. My classes are about 40 students in a very small space. I do not want to use acrylics with such a large unruly class. I was thinking of oil pastel and black ink or black tempera to 'sgrafitto' into. Does anyone have great ideas that work. I want quality work from my students so I need to offer something that works well. The tempera sometimes chips and the ink sometimes doesn't carve through well. Thanks!