Yes, so far the bondo has stuck to the MDF and the plastic quite well. My bondo is drying right now and I am using a "Easybake oven" that I picked up at a yard sale to cure it quicker. Quite an impressive little machine if I do say so myself, the temperature gets very hit and assists in curing process. So far, my work has been mostly trial and error but I think that it is coming out rather well. I'll post more pics when I make more significant progress.