Has anyone tried it "in real life training" to get fresh water from salty seawater? Or to purify urine or other contaminated watersources? I think thats the only uses for the system. Am I wrong? I have not trried the system myself as i live in sweden and the climate wont allow it.<br><br>Stefan<br><br>

Solar distillation of salt water works. I've done it. I am less inclined to purify water solely with one method. I utilise both mechanical and chemical resources, conditions permitting. I have tried solar stills to produce water. Once locally ( Oak Riparian Woodland), The Joshua Tree high desert near Edwards AFB and Death Valley. I tried in spite of believing my references that it will not work. I failed to generate anything but a miniature sauna with perhaps a few tablespoons of water at best. My sweat equity was far greater. AArdvark's efforts were not a failure. He learned firsthand, as did his students.His students hopefully realized there are few steely eyed, charismatic Rambo-McGyver with all the answers. <br><br>

I love getting experience from those who have so much more of it than I. However, sometimes lack of clarity makes me wonder if an issue was addressed at sufficient length and with sufficient accuracy. For instance...<br><br>Chris, you said:<br>"So far, I've found clear, opaque and black listed in various references on constructing one!"<br><br>You also said:<br>"If you succeed remember that a series of holes must be dug after the immediate water has been distilled from the first hole."<br><br>Lastly, you said:<br>"Now try the plastic bag wrapped around living vegetation. As John Wiseman points out in his SAS book, The water may be 50' down. The tree is a natural waterpump."<br><br>However, aardwolfes's original comment was:<br>"...that the green [plastic] would absorb the sun's heat and increase evaporation from the soil underneath." (emphasis added)<br><br>And his original questions were:<br>"Would clear plastic work better? Did I just wait too long?"<br><br>Now, my understanding is that "heat" and "evaporation" were not the point of a solar still. My understanding is that solar stills were designed to take advantage of the fact that plants give off water vapor when they transpire (during photosynthesis), just as animals give off water vapor when they respire. My understanding was that you filled your pit with fresh green plants and covered them with clear plastic. The water comes not from the Earth, but from the fresh plants. The water is given off not due to evaporation, but due to transpiration.<br><br>If this is true, then he didn't build a "proper" solar still to begin with, and thus it should be no surprise that his results were poor. If I understand the theory correctly, the plastic must be clear to let the sunlight through, because plants only photosynthesize when in the sunlight. My understanding also was that you had to constantly replenish the plants as they gave up their water and dried out. And that this was the reason why, as you suggest above, it would probably be better to just tie a (again CLEAR) plastic bag to some leafy green vegetation still on the plant, so it can constantly replenish its supply of water via the natural pump of the root system, as it gives off water vapor during through transpiration during photosynthesis in sunlight.<br><br>Now, I have no experience with solar stills at all, and I have a great deal of faith in your opinions. But aside from your dissatisfaction with their performance, we ought to all at least be sure we are comparing apples to apples. A solar still with no plant material utilizing opaque plastic and a solar still with abundant leafy green vegetation utilizing clear plastic would probably produce significantly different results. Indeed, neither may end up being worth the effort at all, but I still feel a distinction should be drawn between a solar still based on heat and evaporation from the Earth and a solar still based on photosynthesis and transpiration from plants.<br><br>Stay safe,<br>J.T.

You are correct in theory and application. I have yet to see any still produce enough water under the best conditions to justify the physical effort. I can't see digging a 4'X4'X3' hole if my water supply was non existent or critically low. I see little need for a solar still in high altitude snow pack or tropical forest. Solar stills imply HOT, arid or semi arid complexes. Vegetation is usually of reduced leafy material, with subsurface root storage systems containing most of the water. Plastic sheeting is not without use: An expedient shelter, to catch rainwater and fabricate a ground signal. For that use a colored material would be prefered. My strategy is to carry water at all times, a lesson I learned the hard way. I keep plenty of charts, and do my best to augment them with information from locals about traditional catchment basins, small wetlands and seasonal streams. The best of our topos are a finite abstraction and dated.Knowing the water finding stategies of the fauna is invaluable. With a secure water supply on hand an individual is much better 'equipped' to rationaly secure additional supplies.<br><br>