Basically the plan is to daisy chain many bottles together to form a continuous flow when i pumped water through them.
I'd rather like to insert the top of one, into the bottom of the next and seal with a rubber grommet of sorts.
It's for a solar water heated shower.
I've heard abrasive paste can be used with a piece of notched brass tube. Or i could make a furnace and bring each bottle to a temp in which i could force a hole through it.