[ThermionicScott]

Tires blowing off the rim have nothing to do with defective patches. Either a section of the tube got pinched between the tire bead and rim, or the tire was seated very unevenly on the rim (the primary issue with old non-hooked rims was that the tire bead could shift up or down and find a way to blow off.) One other thing to do after mounting the second bead is to go all the way around and press the sidewall away from the rim with your thumbs so you can ensure that the tube is safely inside the tire. Blowoffs should basically never happen.