Time for some good ideas, People.

We really like screwing the bottles into one another. It cuts down on a lot of evaporation and when bottles get jostled, they remain chained together, preventing dripping on the floor. The chains of bottles help stabilize the system.

However, we are at a loss for how to tell people to cut through the ends of the 1.5 Liter Poland Springs/DeerPark/Ozarka water bottles. Screwing the bottles together requires getting that hole to be just the right size– 1″ diameter.

The plastic is very thick at that point. Here’s what we have tried:

1) Drilling using various bits: spade/paddle bit ($5),

2) Heating a 1″ Outside diameter cylinder. Sitting the bottle bottom on top of it until it burn through.

Criteria for a good solution:

1) Cheap

2) Safe

3) The tool is small and light so it could fit in kit packaging.

Ideas?

Hugh and I realized that we could give the column of water bottles more structural integrity if we could tightly screw them into one another.

It was a matter of finding the right tool to get a tight fit. Just the right sized hole in the bottom of each bottle for the next one’s mouth to screw in tightly. Then you just drill a hole in the cap and put it back on to double the connection strength.

This is absolutely beautiful. I’m pretty sure we’re going to need tubing in this cap, but right now it just looks “right”.

The whole chain with water. We didn’t drill large enough holes in the caps of the bottles to allow a continuous run of the pump. Note the overflow. It MIGHT be a good idea to drill a 1/4 inch hole in caps and insert a piece of tubing to bring the fluid outlet below the level of the plant hole.

A view from the top. We’re about to turn on the water.

Yes, it’s strong. That’s 15 lbs suspended from the chain, and it didn’t flinch. Once we come up with a more refined process, we’ll test it to its failure point.

Behold the glorious food chain – The bottle bottoms were drilled, other bottles were inserted, and secured with the caps through the “plant hole” cut in the side of the bottle.

Buy something cheap like this on ebay for $15 and unless you try to drill bricks, you’ll have it for the rest of your life.

Behold the Unibit. This is THE best way to drill the bottoms of plastic bottles, and really once you have one of these drills, you don’t need many others to do the job. This particular one only goes up to 1/2” in diameter, but other styles are far larger. These are also called “step drills” and they work wonders in steel and many other materials.

A standard wood cutting 1” hole saw is a much better choice for drilling the bottle bottoms, and they’re available at hardware stores and home depot / lowes .

Using a 1” wood boring bit to cut the bottle – This worked quite poorly and is not an appropriate choice for drilling plastic bottles. These things are tricky, since the thickness of the plastic varies dramatically along the bottom of the bottle as you move away from the center.

The neck of the average water bottle is just shy of 1+1/16 of an inch. We used a 1” bit, and the poor quality of our fixturing (holding it by hand) gave us the perfect amount of over-cut to give the appropriate fit.