Crafting bloody effects is super entertaining, but when it comes to squibs, those little explosives that filmmakers use for bullet impacts, it's not all fun and games. These things can not only be dangerous in untrained hands, but using them requires permits that you may not have the time, money, or desire to deal with. But John Hess of Filmmaker IQ shows you a nifty way to circumvent all of the explosive stuff by making an air-powered squib rig that produces results that are just as good. Check out the tutorial below:
Hess walks you through the entire process, including how to put together the blood delivery system, choosing the propellant that's right for you, and rigging your talent, which is the most difficult part of all. For the tutorial he uses a standard air compressor with a pressure gauge so he can get it to the right PSI for the squibs, which he says should be between 20-30.
This method of using squibs is a lot safer than how it's traditional done and won't require you to apply for permits or hire a professional special effects artist. You may have a more beefy rig to hide, but a little creativity and visual trickery can help you get away with a lot.
Source: Filmmaker IQ