How hard can it be to make a battery cap you ask. One of the hardest parts of this build. I made them out of metal and screwed them in. Made some out of rubber like a plug. Finally I made them out of plastic. Tried to make some that glowed red when you pulled on it. That made it look like a toy. Made some with a slot, for a coin to fit in. That didn't work. Came up with the drop and turn system that I'm using now. One thing I always wanted the pipe to do is, puff some
vape out of the bowl when you blow back through the pipe. I tried all kinds of hole patterns and came up with the six angled holes that make a nice curl on the back puff. It looks like a real pipe. I have been asked to leave
vape shop for smoking inside.