|MadSci Network: Chemistry|
Hi Jake, I can't tell you for sure, but I guess it will be a chemical like sodium picrate or picric acid. These chemicals are very sensitive to friction and burn with very little applied pressure. So you must be very careful with them. The best thing for you to do is to talk to the real experts. Try visiting www.specialefxunltd.com. These guys have had a lot of experience in special effects for many films, and will be able to tell you for sure. Regards, Glenn Miles
Try the links in the MadSci Library for more information on Chemistry.