Instructables

Convert a Electric Water Tank to a Outdoor Wood Heater

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Picture of Convert a Electric Water Tank to a Outdoor Wood Heater
I recently developed an interest in welding and so began looking for a welding project. With winter around the corner I began scanning Instructables for outdoor wood heater inspiration. Lots of great ideas and creative approaches. Many use gas cylinders which are a perfect size but has an element of risk. By chance I came across a dumped electric hot water unit, and even though a bit on the larger size, I thought why not.

Materials & Tools
1x expired electric water heater of any size.
1x 2M length of 100mm round tubing or equivalent for the flue
Reinforcement steal rod
Steal RHS
Steal angle
Angle grinder with scourer pad and cut off discs
Multi Tool
Jig Saw
Welder (Mig)
 
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Step 1: Heater Strip Down

Picture of Heater Strip Down
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To be honest this step started out as a bit of fun but I was over it by the end. The dome top and bottom of the cylinder being the trickiest and therefore most time consuming. The body was relatively easy, just score a grid pattern around the circumference. The horizontal scores were about 30cm apart, the vertical score was the depth of my multi tool blade – about 5cm. Then basically shear the thing like a sheep. As you can see it came off pretty cleanly in rectangular blocks, created a huge mess in the shed, but cleaned up very well. Note that I actually left the bottom section on right up to Step 6, this allowed me to use a spirit level to mark out in the next step.
tooday116 hours ago

nice

-CCCP-5 months ago

Can this smoke meat like deer? Also, I can't weld so I will use a 55 gallon steel drum and just cut holes.

I like the ash box idea. I may have to that on my next build. I have made something similar but it was for a person to dry there pottery. Used the inside of a smaller tank to make the shelf that held the pottery and was able to fire it from three sides and used an air hose to redirect heat back down which also helped keep the fire burning hotter. Great project you have done here.
can you use an old gas water heater in place of an electric one?
Dave2340 (author)  dugthegreat531 year ago
If the heater is based on a metal cylinder then certainly. On the issue of the glass lining, it is starting to flake off. Currently I am looking for some “found steel” (Thanks Phil) suitable to make a box as my Pizza oven. Weather here in Australia is rapidly warming up so won’t be using “Ned” for a while. Hopefully the steel required will cross my path in the summer months and can be cooking Pizza’s by Autumn. Thanks for all feedback, really appreciated. Cheers Dave.
SIRJAMES091 year ago
AWESOME IBLE!! TY for sharing Sir.

about the glass lining.
with a hot enough fire(400 - 500 degrees) it(the glass) should crack & break away...or tap on it while it's hot & that too should cause it to break away.

Either way, I think it to be a smart idea to remove the glass lining B4 cooking any food.
old_alex1 year ago
I would assume this is "glass lined" as are most (looks kind of shiny in the pictures).
How thick is the glass layer and can it be removed?
While it looks like a candidate for a smoker or a pizza oven as you suggest at the end, I would advise against is due to the glass flaking off.

Dave2340 (author)  old_alex1 year ago
The glass is about 1mm or so in thickness. It is very tough and takes quite a bit of grinding to clean the surface for welding. With a fire in it I would expect there will be a lot more expansion than normal. The question now is will this crack the surface and will It break free. I'm not jumping in to the next stage too quickly. I feel it would be best to use as a heater for now and inspect the lining later to see how it has coped. Since posting I have cut off and sealed the input/output ports (5) on the body.
If it looks even slightly off then at best I will need to seal off the oven area. Worst case is I will just have to accept it as a oversized outdoor wood heater - no problem there!
I will update though and let you all know if it is feasible.
Cheers
spylock1 year ago
I would think one would make a good forge also.
EricHi1 year ago
You really did a great job - nice looking too!
rncbme1 year ago
Great Job Dave! Not so much since the price of metals has soared but I used to pick up angle-iron bed frames at the local dump site for free. They are generally a high carbon steel that is hard to cut and drill, but hey, free is free. I've made all kinds of frames and mounts from them.
actionjksn1 year ago
Its actually spelled "steel"
Cool Recycling Project. Nice Work.
Ha ha! First thing I thought of when I saw the pics at the top was "PIZZA!" Funny, all roads lead to Rome sometimes. I'm gearing up to make a wood fired as well, I just liberated two 36" stones from a commercial pizzeria-style steel oven, and I'm getting the brick from this place in Monterey. Mine's a little more traditional, albeit small. Good luck, can't wait to see what you come up with!
Phil B1 year ago
Very nice. Isn't it fun to take scrap and make something useful because you can weld?
Dave2340 (author)  Phil B1 year ago
Phil by day I'm an IT consultant servicing computers for small business clients. Great job really but not at all physical. Which i why the welding and tinkering is so rewarding to me. i hope my first Instructable is well received, i have plans for a couple more developing in my head. Thanks for the first comment on this project.
Dave,

I lived in Chattanooga for a few years. Someone there told me about a local cardiologist who talks with stressed executives. For their own good he sends them to a welding course because it is relaxing. I just retired from 40 years as a Lutheran pastor, which involved dealing with people. I always enjoyed my tools because in an hour or two, I could see the results of my work. It was seldom that way when dealing with people.

I first got a welder about 15 years ago. I learned by reading books and posts on the Internet, and then trying what I had learned. Now there are good videos on YouTube and elsewhere. I always thought welding was like alchemy. You could take scrap and make something valuable from it. My welds could be legitimately criticized on a number of fronts, but none have broken so far, either.

Congratulations on your first Instructable. It seems people with welders are always looking for project ideas. Yet, it is difficult for one person to suggest something for another because needs and interests are so different. I have done some Instructables that make decent welding projects for those whose interests are along those lines.

When I began posting Instructables, I thought I might have ideas for a dozen or so. But, after a while there were considerably more than that. I continue to think I have published the last idea I will ever have, but a new problem arises and needs to be solved, so I document it with an Instructable.

I look forward to more Instructables from you.

Jackn7 Phil B1 year ago
I like all kinds of projects like this, as I have this inherent desire to re-purpose things instead of filling up a land fill.

De-soldering parts from old computer boards and power supplies, then building something from those components. A recent instructable that went about salvaging a Microwave Oven Transformer and converting it to a Spot Welder gave me an idea for converting an old transformer that originally came from a Shrink Wrap machine for the same purpose. :)

All this stuff is great!

I also love to work with wood.

Making use of what you have available is always a great brain exercise! ...and you are right, much more relaxing than dealing with people... hah hah!
Not to put a cloud on your project but you should know that welding galvanized metal is extremely hazourdous and the effects would make you cringe. Please scrap the galvanized stuff it is not worth your health. I would suggest looking around for an pld 100# propane tank, remove the valve after you make sure there is no propane in it and fill with water then empty and you are good and safe.
Dave2340 (author)  wisconsinjimmy1 year ago
In the research for the project the issues with gal came up quite a few times. I used a grinding disc to clean the area well before starting. when actually welding i was in the open garage doorway with a fan blowing across the work to minimize the fumes. Also welding is short bursts also helps. Thanks for the concern, definitely needed to be clarified.
streetrod51 year ago
Dave, great job, good, clear pictures and a fun build! I've always wondered what a water heater looked like inside, but was afraid to ask. Very useful project. I bet you could run water pipes through to provide a little extra hot water (say for an outdoor shower, or to wash the car).
We replaced an electric water heater a couple of years ago. I did not think much about using the tank like Dave did; but, the water heater was in the basement and the tank weighed a lot, so I cut it up and got some money for it at the scrap yard. I did save the outer skin of the water heater and have made several useful things from it. Things like this are "found steel."