First time bottom feeder mod questions

[Commie]

I'm working on a new copper mod, and looking for suggestions/ideas

1. Is there a trick to drilling a copper endcap through the center? I punch mark them, but they always seem to come out just a bit off-center

2. Do you know of any juice bottles that would fit inside a 3/4" copper pipe? Yes, it'll be an attempt at a bottom feeder mod

3. Is soldering two copper pipes side by side sufficient to hold them, or should I bolt them together as well?

4. Is there anything freaky I should know about bottom feeder mods? I assume it's just a dripcup with a 510 connector in it, with a bottle feeding juice through the connector, right? Or should there be some additional juju to it? And the dripcup is delrin, not copper

Thank you!
Commie

 

[asdaq]

Let me see:

1. A drill press with decent vise would help, or use a step drill as you can correct by leaning between steps.

2. A 6ml bottle is just about the same dimensions as a 18650, a 3ml is like a 14500.

3. Solder will do, but a torch or higher wattage iron is needed as all that tubing acts as a heatsink. The hardware store's soldering iron is meant for plumbing more than for electronics, a 60W with chisel tip is good for this.

4. If you are using a 510 connector, I would include an 18G syringe needle to feed the liquid, and use RC car/plane fuel line (silicone, unused) to seal from the bottle's nipple to the bottom of the connector. I'm not so sure on the size anymore, but there are a bunch of ways to do this, and this is just one idea.

Cheers, and happy building.