Self explanitory, how is ripping an arm off using fxhome possible?

Using EffectsLab, it would be really hard. But I'd just use masking and stock footage (for the arm stump or some such). Yeah though...Elab is not the program for that kind of stuff. I'd use CompositeLab or VisionLab. Just heads up.

this will show you how http://www.youtube.com/watch?v=izbbKhHKsgk

do it old school

make a false arm, have your actor do the scene up to the point of the rip.
from a different angle ( with the actor's arm under the shirt, around his back), rip the arm and what ever part of the shirt off, control blood with a sprayer filled with blood