What plastic for solar stills?

**RandyRhoads** · 07-30-2013, 09:36 PM

Does anybody have a specific type of plastic or anything they use for solar stills? Should it be some sort of food grade plastic, since it will be heated up with water? I'm sure chemicals have to leech out into the water. Anybody care to share what they have in their kit, size type shape?

**welderguy** · 07-30-2013, 10:00 PM

I have two types of plastic in my bag ,plane old Trash bags, and a painters tarp ( the cheap disposable type). have used both with some success and water tasted ok.

**RandyRhoads** · 07-30-2013, 10:03 PM

Ok, are they clear trash bags? Does plastic that's not clear provide less results? It seems like water in solar stills would definitely leech chemicals out of it.....

**welderguy** · 07-30-2013, 10:08 PM

Originally Posted by RandyRhoads

Ok, are they clear trash bags? Does plastic that's not clear provide less results? It seems like water in solar stills would definitely leech chemicals out of it.....

The painters tarp is clear, and the trash bags are white. I didn't notice a big difference in what little water i did get to say there is a difference in clear or a color plastic. I never really gave it much thought about the chems leaching to the water, I have no idea about that one.

**welderguy** · 07-30-2013, 10:09 PM

I have not yet tried to use a black trash bag for a solar still, and since black seems to draw more heat than any other color it may work better than the clear. just a thought.

**RandyRhoads** · 07-30-2013, 10:19 PM

That's actually a good thought. Maybe i'll do a little experiment. For some reason I assumed only clear would work.

**welderguy** · 07-30-2013, 10:37 PM

Originally Posted by RandyRhoads

That's actually a good thought. Maybe i'll do a little experiment. For some reason I assumed only clear would work.

I haven't had the time to try the black ones yet. If ya try it let me know how it worked out for ya.

**Rick** · 07-31-2013, 07:45 AM

They won't leach significant amounts because your are not heating them high enough to cause the chemicals to separate. However, all plastics will leach trace amounts simply by touch. No different than placing food in a zip lock and putting it in the fridge or freezer. You are probably safer from chemicals using any type of plastic for a solar still than you are from the plastic liner in food cans.

**Cast-Iron** · 07-31-2013, 08:26 AM

I look at solar stills as a survival tool. Dehydration will kill you within hours or days depending upon environmental conditions.

I think any solid plastic sheeting should work as all you're really doing is capturing and condensing evaporation. However when I performed this years ago as a young scout, and in every example I have seen since, clear plastic has been used. I guess it helps you to monitor the operation without having to open it up and also insures your plastic is weighted directly over whatever container you've selected to place at the bottom.

**gryffynklm** · 07-31-2013, 09:38 AM

I use a clear plastic because the evaporation comes from ground moisture. It seems to work better if earth under your plastic warms up to speed the evaporation.

**finallyME** · 07-31-2013, 10:17 AM

A solar still works by heating the impure water, which evaporates, and then condenses on the cooler plastic. A clear plastic will let more light/heat pass through it, therefore it would be cooler that the evaporated water. For leaching plastics, the big scare recently was for BPA, which is found in Polycarbonate. Polyethylene and PVC does not have BPA. Good luck finding a thin flexible polycarbonate sheet of plastic. Trash bags and plastic painters drop cloths are all PE. Clear PVC is also a common plastic sheet. That doesn't mean there aren't chemicals in those plastics, just not BPA.