This video shows, in an easy step-by-step fashion, how to build a solar bulb from a plastic bottle, some metal sheeting, rubber sealant or epoxy resin, glue, filtered water and 10 ml of chlorine.
1) Always scratch the sides of the bottle to create better grip to the sealant. The top part where the bottle meets the metal is the leak point in the build so use industrial strength sealant (epoxy or DOW Corning 791) on the top and bottom if possible.
2) Always put a protective cover over the bottle cap as the suns rays tend to make the original bottle cap brittle and a crack in the bottle cap will allow the water in the bottle to leak during evaporation.
3) Always RIVET the metal sheet holder on to the roof.
4) DON’T USE THIN METAL ROOFING SHEETS. There will be no bite on the plastic bottle and the different expansion rates will cause leaks later on. Go for thicker roof sheet.