Here you go Bob
This is made from a Pepsi bottle.
The material list is:
1 Pepsi bottle
1 Vigoro Sweeper Nozzle
1 O-ring or garden hose gasket
Approximately 10” of ¼” I.D. vinyl tubing
3 zip ties
Dark flat spray paint
Approximately 12” of small rope
Duct tape (of course)
Here is what I did:
I removed the label from the bottle and applied a strip of tape vertically down the bottle. This strip of tape went from the neck of the bottle to the base of the bottle.
Next I painted the entire bottle with a flat dark primer. Any dark color paint will work but I think it should be flat. Once the paint dried I removed the tape. This left a portion of the bottle's interior exposed so I can see how much liquid is in the bottle.
While the paint was drying I heated a pan of water and once bubbles started to show on the bottom of the pan, I dipped one end of the vinyl tubing in the water and held it there for a few seconds to soften the plastic. When I thought it looked soft enough I pulled the tubing out of the water and I pushed the heated end of the tubing onto the brass nozzle.
Once the tubing cooled on the nozzle, which only takes a few seconds, I began to coil the tubing and hold it in place with the zip ties. After experimenting with the coil amount, I found that a coil of 1.5 turns worked well for this setup. I cut the length of the tubing so that it would end at the height where the nozzle screws into the bottle.
After coiling the tubing, I added an O-ring to the inside of the nozzle. Then I taped some rope to the lower end of the bottle, filled the bottle about ½ full of water and then screwed on the nozzle assembly.
To test the dripper, I hung the bottle in full sunlight and counted the drips in a five minute time period. When I was testing it was 6:00 PM, no clouds and 80 degrees. In the environment that I described I was getting 7 drips in a five minute time period, but once the sun started to dip behind some trees, the dripping stopped. So, this setup will need a place where it will get full sunlight for a portion of the day for it to work. I'm sure the commercially made drippers work this way too.
The sweeper nozzle came from Home Depot and cost $3. The tubing I had on hand, but Home Depot was selling tubing for $3 for 10’. So providing that you have all the materials except the tubing and the nozzle, you can make one of these for $6. If you want to add a wick to the tubing, call Mike at The Nocking Point. He sells alcohol burner wicks for $1.50.
Here are some pictures.