A Portable Solar Water Heater

Enlarge Image Image Gallery Learn how to make a simple, inexpensive solar water heater that you can take anywhere. MOTHER EARTH NEWS STAFF

Most of us have — at one time or another — longed for the luxury of a hot shower while on the road or trail. Well, there's no need to yearn any longer, because I've come up with a portable solar water heater that will cost you less than $10 to build and can be folded and carried in a backpack, suitcase, car or boat!

Not only that, it's also amazingly easy to construct this heating unit. Here's what you need to put one together: one auto inner tube, a length of used garden hose, a 1/2-inch plastic pipe coupler, a small clamp, a male hose connector, a hose valve or nozzle, and some good-quality rubber-sealing compound.

Here's How to Build It

It's generally possible to scrounge up a free, secondhand inner tube in good condition, or — at worst — buy a used one for no more than $1.50 from a tire shop. When you select yours, keep in mind that a 14-inch tube will hold around 19 quarts of water. (If you want greater or smaller capacity, simply go up to a 15-inch truck tube or down to a 13-inch compact car size.)

Once the tube proves to be sound (just inflate it to find out if it has any leaks), use a sharp pair of scissors to cut a 1/4-inch hole (see Photo 1 in the Image Gallery) about two inches in from the outside edge. Now, wet your finger with water, stick it into the hole, and clean around the inside.

Next, take the 1/2-inch pipe coupler and cut off its lower half (see Photo 2), glob a good amount of rubber-sealing compound on the small ridge of the coupler (as in Photo 3), and push it into the 1/4-inch hole. (This task may require a little effort, but — to make it easier — you can leave the tube in the sun for a while to soften up the rubber.)

With the lower part of the coupler in the hole, pull the ridge up snug against the inside of the tube and let the cement dry for the maximum time stated on the product's label. (Remember, if it doesn't dry properly, your seal will be worthless.)

That done, clean around the "new" stem, and roughen that area just as you would the space surrounding a hole in an inner tube that's to be patched. Now, put some rubber-sealer on your finger and coat the outside area (see Photo 4). I've found that three thin coats will dry faster and provide a stronger seal than one large glob. Again, let the cement set completely.

Then, all you have to do is take about two feet of old garden hose, connect it to your new stem (if you have a problem slipping the hose on, let it, too, sit in the sun for a while to soften up), and put a clamp around the hose and stem to hold them together.