How to build a free wood-burner
by JO HOOPER on OCTOBER 15, 2007 - 15 Comments in urban
water_heater.jpg
Not an oil drum

DIY wood-burning stoves are usually based on an old 55-gallon drums. They more or less do the job, but they’re inefficient, difficult to regulate, and so ugly that most people will only tolerate them in the garage or workshop.

The best thing about them is the price. Or at least it was. Lately, though steel barrels have become increasingly difficult to find … and, when you do locate one, it frequently has a hundred dollar price tag at fixed to it.

There must be a better way to go about assembling a homemade wood-burning stove. Try a discarded electric water heater tank, for four good reasons:

1. The walls of a water tank are four times as thick as the metal in a 55-gallon barrel … which means that a water heater drum will make a much tougher stove and will last a lot longer.

2. when you build a firebox from a junked water heater tank, it’s very easy to make the stove as airtight and efficient as any $2500 woodburner on the market. And we can’t say that about a 55-gallon-drum stove.

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3. if you construct your heater right it’ll be easy to load, it will have excellent fire and temperature control, and it’ll look classy enough to put on display right in the living room.

4. You can build one a water heater stove for even less than a 55gallon-barrel wood-burner. As a matter of fact, you can scrounge up everything that goes into it. Which means that the stove costs only the labor – one good long day.

IT WORKS

You can warm an entire 1,100square-foot house with one of these and be amazed at the large amount of heat and small amount of ashes the unit produces. You’ll also be pleasantly surprised by the way the heater holds a fire overnight.

THE SECRET OF THE LOW COST STOVE

Once you’ve found your “junked but still in good condition” water heater tank, you’ve already got about three-quarters of your stove “custom made” just the way you want it.

And it really isn’t difficult to find one of these tanks, either. Most of the landfills scattered around the country, in fact, are so filled with the containers that we’ve developed a sneaking suspicion the old water heaters breed out there.

Any discarded electric (forget the gas ones for this project) water heater from 30- to 50-gallon capacity will convert nicely into a stove. However, a 30-gallon tanks (with a diameter of 20 inches and a length of 32 inches) makes the best-looking wood-burner of all.

Pick and choose a little from your local landfills, dumps, or the alleyways behind appliance stores until you find just the tank or tanks you want. Then (if you’re doing your “shopping” in a landfill or dump) strip off the lightweight sheet metal “wrapper” and insulation right in the field and make sure that the main tank inside isn’t rusted out or filled with corrosion. Or, if circumstances dictate, you can do this stripping back home and then haul the castoff sheet metal and insulation back to the dump when you’re ready to discard them.

stove diagram
Stove details

THE REST IS EASY

Anyone with a cutting torch and welder will find the rest easy. And if you don’t own or operate such equipment, scout around until you find a competent welding shop that’ll convert your tank at a reasonable price (i.e. a big drink).

Lay the container on its side and add legs and the “loading hopper box with hinged lid” as illustrated in the accompanying drawing. Then weld in the “exhaust stack” or “smoke boot” . Make sure that all seams are airtight and that the hoqper box lid fits snugly (airtight) too. he draft control is, perhaps, the most critical part of all. If it’s well made and doesn’t leak, you’ll have good and positive control of your finished stove’s blaze and temperature at all times. Conversely, if it isn’t well made and it does leak, you won’t. Work carefully and do the job right.

Once the stove is completely assembled, paint all its outside surfaces with Rustoleum Bar-B-Q black paint or “high temperature engine paint”. You’ve just built yourself one mighty fine wood-burner!

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15 comments

1 EcoLinking - 18 October 2007 at EcoStreet - Raising Green Consciousness since 2002 { 10.18.07 at 12:41 pm }

[…] How to build a free wood-burner at off-grid […]

2 DaveBoat { 10.25.07 at 6:35 am }

Like this idea very much, would like more details from someone who has built one, more pictures, drawings etc. I am looking for a small efficient wood burner capable of heating water as well as for cooking on, any recommendations. I come across so much scrap wood for nothing on my travels, though it is mostly softwood, which tends to burn too quickly. How could this design be adapted to suit my requirements, Suggestions please.

3 Gregory Gray { 03.24.09 at 8:59 pm }

Where is the door to load it? If you can make one out of a old water heater, can two be welded together to make a longer one for longer logs?. The reason i ask is because i own 80 acres of hard woods and can’t see cutting the wood in such small pieces. I could put logs in it instead of small pieces.

4 Diana Davis { 04.16.09 at 4:07 pm }

Is this type for use outdoors, if so do you need to build something to keep this in ?

5 Doug { 12.06.09 at 7:28 pm }

Anyway to get some plans on this/

6 ftwtim { 12.08.09 at 1:13 pm }

@Doug
Yes you can get the original plans and description from the motherearth website, and, also down-loadable plans.

http://www.motherearthnews.com/Do-It-Yourself/1978-01-01/The-Amazing-500-Wood-Burning-Stove-That-You-Can-Build-for-35-Or-Less.aspx

7 ella spurrell { 09.13.10 at 1:59 pm }

hi we just install a wood burning stove that was made out of hot water heater and our wall behind the stove gets really hot is there anything that we can put there so the wall won,t burn we all ready have ceramic tiles

8 Wretha { 09.15.10 at 8:49 pm }

ella spurrell, we have used cement board behind wood stoves that were near a wall, one trick is to leave an air space between the cement board and the wall, a couple of inches should be good. You can cover the cement board with tile or a sheet of metal (copper, stainless steel…).

Wretha

9 Cyndie Malik { 10.29.10 at 9:08 am }

Will this work with pellets and corn cobs or just wood?

10 tarkas { 12.26.11 at 5:20 pm }

I built the water heater stove in your illustration ( it was originally in Mother Earth News circa 1980)
in 1981. used it to heat my mobile home then the 1600 square foot house that I built. The thing worked very well. I even burned Bois’d arc (horseapple) wood in it. The thing may still be in service as I sold it in 1985.

11 ali samer { 01.14.12 at 2:10 am }

i hope to learn and things

12 cory long { 10.31.13 at 8:57 pm }

i got a 275 gallon oil tank
wood stove
burns lots of logs
i get a good fire going than i filler up with dryed split oak logs
for a very long hot burn
it burns for 3 days
with air control turned down

13 WilliamT { 11.09.13 at 5:23 am }

Sounds pretty good but most water heaters are replaced because they rust out and start to leak.It might take some serious work to find one that is in useable condition.

14 Wade Carpenter { 12.09.13 at 11:31 am }

Cory Did you buy a door or make one?? & do you have any pics of the oil tank stove??
Thanks
Wade

15 cynthia { 03.16.14 at 8:37 pm }

want info on building an outside unit to heat my home

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