I have in the past made double chambered solar stills with three clear plastic bottles - 2 2 litre, 1 1 litre/20oz, duct tape and rope. It is based on the bottle compost design.

The tricky part is cutting the 2 litres to be able to put the 1 litre in and taping it up again. You cut the top off of both of the big bottles(about where you see the curve in starting for the top cone) and throw one of them away. Excuse me, recycle it! <img src="/images/graemlins/smile.gif" alt="" /> Turn the remaining top over so that the cone is pointed down into the bottle. Make sure it will fit without falling in. take it back out again. Measure the bottom of the smaller bottle and cut the very top off of the cone about 1/4 inch smaller than the small bottle. Cut 'tabs' and force the small bottle into it with the cone facing down. To make it easier for condensation to get to the bottom bottle, you may want to make holes in the cone, too or cut one or two of the tabs completely off.

Put the 1 liter in the cone(careful!) and put the other bottle bottom over top ofit. Tape up.

Oh, I guess I should mention one minor thing to do before taping it up - You place water in the small bottle. 1/2 full is good, more and it can tip over and spill. Things that can make it better include twigs or cooking skewers inside to keep things propped up, black paper or paint for the top bottle and a good brick wall or big rock for thermal mass.

The rope is to hang the bottle contraption in a tree or from the eves of a house.

I was able to capture about 4 oz of 'distilled' water in a 36 hour period from about 8 oz of crappy water put into the small bottle. Not a great method, and not a great producer, but good to put in a camp when you know you are going to come back in a few days.

Just a thought brought on by the mentioned solar reflector... (my thighs in summer...)

Rena