so i'm in vault 19, and i want to blow up the whole vault, so im helping Lem. i have 54 in explosives, and i don't have any C-4... i already raided vault 34, and broke the detonator, and used the C-4, lol... can anyone tell me where i can buy or find 5 C-4 and a detonator?

Novac, inside the dinosaur. Be sure you have the caps though.

■7 can be found just inside the entrance of Camp Guardian Caves.

If I remember right, you don't need the detonator. It's activated by the substance in the caves. Check the Wiki.

http://fallout.wikia.com/wiki/C-4_plastic_explosive