I was looking through Army FM 21-76 and reading about the Solar Still - can you get enough water out of one with say... a poncho sized piece of plastic to sustain, or will it just be enough to supliment? Also, what kind of vegetation should you line your hole with (leaves and such, or more plant roots)?
Solar Still
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From what I've read, the solar stills don't really work - or at least not as well as you'd want. Use of "transpiration bags" - large clear plastic bags over tree/bush branches - provide a better source of water.
I buy large clear 55 gallon plastic bags from Home Depot.
See http://www.equipped.org/watrfood.htm
I buy large clear 55 gallon plastic bags from Home Depot.
See http://www.equipped.org/watrfood.htm
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DO NOT RELY ON THE SOLAR STILL AS A SOURCE OF WATER... you will sweat far more water than you will gain.
Myself and two other young men built one under ideal conditions in a riparian zone of the Sonoran Desert with Cody Lundin watching. In fact the 5' wide by 3' deep hole could have been used as an Indian Well to give you an indication of how much moisture was present, however, we went through the exercise of making a solar still. If I remember correctly, we yielded almost 3 quarts of water in 24 hours. Cody said it was one of the better producing solar stills he had seen. The only problem is, in the 1.5 hours it took to make digging with sticks, we drank almost a gallon.
Also, making the still isn't as easy as it looks. You have to seal your plastic at the edges with little room for error - as to capture moisture, allow for the water to run to the center, and not collapse the wall.
And to reiterate, we had ideal conditions and 3 able body men. The solar still is not worth it in a survival situation.
Myself and two other young men built one under ideal conditions in a riparian zone of the Sonoran Desert with Cody Lundin watching. In fact the 5' wide by 3' deep hole could have been used as an Indian Well to give you an indication of how much moisture was present, however, we went through the exercise of making a solar still. If I remember correctly, we yielded almost 3 quarts of water in 24 hours. Cody said it was one of the better producing solar stills he had seen. The only problem is, in the 1.5 hours it took to make digging with sticks, we drank almost a gallon.
Also, making the still isn't as easy as it looks. You have to seal your plastic at the edges with little room for error - as to capture moisture, allow for the water to run to the center, and not collapse the wall.
And to reiterate, we had ideal conditions and 3 able body men. The solar still is not worth it in a survival situation.
They may work a little better in Less arid circumstances.
3 quarts in 24 hours in the Sonoran is amazing!!!
In less arid areas, You can pack them with green leafy vegetation to get more water from them.
I agree I wouldn't depend on it for much more than about 10% to 20% of my needs, but, it's still one of the viable ways to collect "some" water.
An anology would be survival food collection. Don't simply depend on your single fish hook for all your food needs. Set traps, hunt, fish, find insects, bird eggs, edible plants, etc. etc. to round out as much of your needsas you can.
3 quarts in 24 hours in the Sonoran is amazing!!!
In less arid areas, You can pack them with green leafy vegetation to get more water from them.
I agree I wouldn't depend on it for much more than about 10% to 20% of my needs, but, it's still one of the viable ways to collect "some" water.
An anology would be survival food collection. Don't simply depend on your single fish hook for all your food needs. Set traps, hunt, fish, find insects, bird eggs, edible plants, etc. etc. to round out as much of your needsas you can.
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Again, the conditions were ideal. The hole we dug had standing water when we got to three feet, we continued it as a solar still as a test knowing we get a good yield as there was also full sun and we weren't under any adverse conditions to set-up the still. Even with these conditions a solar still is not a viable option.
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I have only done it a couple of times and 3 or 4 ounces is all I ever got. Good return for the effort; didn't taste all that great though.
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"DO NOT RELY ON THE SOLAR STILL AS A SOURCE OF WATER... you will sweat far more water than you will gain."
My experience in Brazil conforms this. I dug a solar still up on a waterless ridge and it yeilded a few ounces of water. I also used the same size clear bags to bag branches and they yeilded about the same amount of water as the still but without the price in sweat.
I do get results quite often digging for water and if the hole got deep enough in a place that I was hoping to dig down to water I would then, and only then, consider making a solar still out of it. I would also consider making a solar still on a beach where there is a ready supply of seawater to feed into it. If the hole was saturated with saltwater it would probably yeild a decent amount of fresh water.
On the same trip that I tested the solar still and bagged branches I woke up in the morning to heavy dew. In an hour and half I was able to collect 1.5 LITERS of water. By far dew collection was my best option.
Other water collection methods I've found worked well are using a 60 ml syringe to suck water out of plants where it gat caught, and drilling bamboo. Digging about a half km back from a beach once yeilded a small well about 1 foot down, the water was slightly brackish but definately potable.
I think digging a solar still is a good exercise but not one I'd put my hopes in. The bottom line, you pay too much in sweat for what you get out if it. Mac
My experience in Brazil conforms this. I dug a solar still up on a waterless ridge and it yeilded a few ounces of water. I also used the same size clear bags to bag branches and they yeilded about the same amount of water as the still but without the price in sweat.
I do get results quite often digging for water and if the hole got deep enough in a place that I was hoping to dig down to water I would then, and only then, consider making a solar still out of it. I would also consider making a solar still on a beach where there is a ready supply of seawater to feed into it. If the hole was saturated with saltwater it would probably yeild a decent amount of fresh water.
On the same trip that I tested the solar still and bagged branches I woke up in the morning to heavy dew. In an hour and half I was able to collect 1.5 LITERS of water. By far dew collection was my best option.
Other water collection methods I've found worked well are using a 60 ml syringe to suck water out of plants where it gat caught, and drilling bamboo. Digging about a half km back from a beach once yeilded a small well about 1 foot down, the water was slightly brackish but definately potable.
I think digging a solar still is a good exercise but not one I'd put my hopes in. The bottom line, you pay too much in sweat for what you get out if it. Mac
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Great first-hand information, Mac!
Could you go into a bit of detail on dew collection methods?
I did a quick google on dew collection and ran across this report that indicated that water gathered in this manner should still be purified. I was suprised.
-- FLIX
Could you go into a bit of detail on dew collection methods?
I did a quick google on dew collection and ran across this report that indicated that water gathered in this manner should still be purified. I was suprised.
-- FLIX
Alan Molstad
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When I was a kid, and was watching the NASA guys getting ready to go to the moon... I saw how they were teaching them how to live in areas of the world where they might have to land.
One of the things they were taught to build was the "Solar Still "
So, my broither and I went out in our field and made about 10 of the Solar Stills.
Do they work?......well....sorta...But I would NEVER try to drink the few drops of water we were getting.
When I was in my 20s they started to write books about staying alive in the wilderness, and one of the first things I read about was what a bad idea the whole "Solar Still " turned out to be.
I read that when the experts went out into the bush and tried to build the needed Solar Still to get enough water to live on, that it's just not worth it at all.
One interesting thing my brother and I learned:...
While we were digging the Solar Still holes , (that we would later cover with the clear plastic), we had the plastic spread out on the grass.
We noticed that we started to get drops of water on the underside of the plastic almost right away.
Turns out we got more drops of water forming on the plastic just sitting on the grass than we ever got out of the Solar Still concept.
One of the things they were taught to build was the "Solar Still "
So, my broither and I went out in our field and made about 10 of the Solar Stills.
Do they work?......well....sorta...But I would NEVER try to drink the few drops of water we were getting.
When I was in my 20s they started to write books about staying alive in the wilderness, and one of the first things I read about was what a bad idea the whole "Solar Still " turned out to be.
I read that when the experts went out into the bush and tried to build the needed Solar Still to get enough water to live on, that it's just not worth it at all.
One interesting thing my brother and I learned:...
While we were digging the Solar Still holes , (that we would later cover with the clear plastic), we had the plastic spread out on the grass.
We noticed that we started to get drops of water on the underside of the plastic almost right away.
Turns out we got more drops of water forming on the plastic just sitting on the grass than we ever got out of the Solar Still concept.
Alan Molstad
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well...it would work....however there is the "bugs" question to always keep in mind...
It's just something my brother and I noticed, t
That the fact is, it was hard to keep the plastic that was on the grass dry...
At the time we felt this was a hassel as it screwed up the results of our testing the solar still...
But thinking back now on it....
It's just something my brother and I noticed, t
That the fact is, it was hard to keep the plastic that was on the grass dry...
At the time we felt this was a hassel as it screwed up the results of our testing the solar still...
But thinking back now on it....
RokJok
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Simply "wipe" gently the wetted surfaces with a sponge, cotton bandana, t-shirt, etc, then wring the water out.
An interesting read, including dew collection as primary water source in an emergency situation, is this story on equipped.org.
Couple of things I noted in that report:
1. It was on the island of Corsica, France. IMHO purification may be less needed gathering dew from an American wilderness. I suspect pesticides would likely be a bigger concern here than the high levels of aluminum & iron they found on Corsica as the main pollutants.
Note that a simple straining filter will not remove either the metals they objected to or the pesticides I mentioned. Distillation will. I am not sure if an activated charcoal filter would remove them or not. I think it will get pesticides out.
2. The aluminum and iron levels they noted were simply compared to some organization's standards. For the hopefully short time you would need to employ this method for your drinking water, you would not accumulate enough of these elements to deteriorate your facilities.
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Dew collection is no great secret. If you've ever walked through tall grass in the early morning your pants get soaked. Its just a matter of making the process work for you. I use a clean cotton cloth but any T shirt will do. It helps to have a wide mouth container to wring out the cloth into. I had used a canteen cup on that trip.
Just keep swiping the cloth through dew soaked brush and grass until its wet enough to wring out and keep at it until you have enough water for your day. If you start early enough you can get enough to keep hydrated before the dew burns off. You do have to get up before sunrise. The good part is that your doing all that work when it's cool out so you don't pay for the water you collect in sweat.
I have heard of people getting very clean water from this method but that AIN'T the case in central Brazil. We have alot of dust that settles on everything and soaking up the dew results in muddy water that needs to be filtered and treated.
The downside is that quite often you don't get any measureable amount of dew so the technique is seasonal. There is no substitute to trying these expedient water techniques in the places you may need them and at the time of year it might be necessary.
For me this is a dry season technique (July). In January all I have to do is look up and open my mouth. Mac
Just keep swiping the cloth through dew soaked brush and grass until its wet enough to wring out and keep at it until you have enough water for your day. If you start early enough you can get enough to keep hydrated before the dew burns off. You do have to get up before sunrise. The good part is that your doing all that work when it's cool out so you don't pay for the water you collect in sweat.
I have heard of people getting very clean water from this method but that AIN'T the case in central Brazil. We have alot of dust that settles on everything and soaking up the dew results in muddy water that needs to be filtered and treated.
The downside is that quite often you don't get any measureable amount of dew so the technique is seasonal. There is no substitute to trying these expedient water techniques in the places you may need them and at the time of year it might be necessary.
For me this is a dry season technique (July). In January all I have to do is look up and open my mouth. Mac