Find the Perfect Electric Water Heater With This Hydrostatic Pressure Test

Use the easy-to-make hydrostatic pressure test stand described in this article to convert an old electric water heater into a storage container, air bomb or much more.


| March/April 1978



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Thar she blows! MOTHER's easily constructed, hand-operated hydrostatic pressure test stand finds the flaw in a defective water heater tank.


PHOTO: MOTHER EARTH NEWS STAFF

One of the most overlooked sources of shop project raw material here in the U.S. and Canada is the friendly, neighborhood landfill or dump. And some of the most underrated items "free for the takin'" in most of those dumps are the hundreds of old electric water heaters that such scrap heaps always contain.

There are so many handy things that you can do around the farm, small family homestead or even city or suburban house with old water heaters. And especially with the stripped-down, heavy-walled, sturdy pressure tanks that you'll find just inside each heater's lightweight sheet metal jacket and layer of insulation.

You can make the tanks into composters. Convert 'em into rodent-proof storage containers for livestock feed. Add the necessary fittings to make a king-sized "air bomb" (high pressure air storage container) for your workshop. Or recycle one of the drums into a super-good-looking, super-efficient wood-burning stove.

One small word of caution, though, before you begin any of these — or other — projects: Don't try to make a silk purse out of a sow's ear. There are so many good tanks out there in the dump just waiting to be hauled off that there's no need to waste your time fiddling around with water heater tanks that are filled with corrosion or which have rusted through.

Now it's not too difficult to roll one of the heavy-walled drums around a time or two, turn it up or peer into one of its openings and figure out whether or not the tank is filled with corrosion. Nor is it any great trick to spot one of the containers that's really rusted out. The stumper is sorting the "perfect" tanks from the "almost perfects" ... the "completely airtight" drum from the "completely airtight except for the poorly welded or rusted-out pinhole on one seam" container.

(For some recycling jobs, of course — say, the construction of a composter or livestock feed storage unit — there's no need to get so persnickety when "shopping" for raw materials down at the dump. For other projects, however — things like an airtight stove or a workshop air bomb — only "the best of the best" is good enough. In the first case, the stove, because of pride of craftsmanship as much as anything. And in the second, the air bomb, because you don't want an unexpected rupture of the pressurized tank to blow your head off someday.)

jim taylor_4
6/11/2009 2:16:36 PM

Just make sure to use cold water for testing. DON'T use air! If you do and the tank blows, it will shatter and spray shrapnel.






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