Our current home is a 400 year old cave house in the mountains so it sort of comes with the territory that there isn’t any kind of central heating! Although we have an open fireplace it is incredibly inefficient at burning fuel and most of the heat disappears up the chimney. With two small children in the house it isn’t the safest option either. The solution to our problem seemed fairly obvious, we needed a woodburner, but at £100+ for even the smallest stoves we decided to think outside of the box and come up with a more DIY approach and made our own.
We were racking our brains for a while about what we would use and how we would do it when it struck me that the gas bottle from our butane heater offered the perfect solution. We managed to acquire an empty gas bottle for the princely sum of 8 euros! To be honest that is the full extent of what our new stove ended up costing us, the few other trinkets we already had lying around but would have cost very little to obtain regardless.
(Editor's notes - WARNING: Working with gas bottles is inherently dangerous, all suitable precautions should be taken. If you’re not sure, don’t do it.)
Make the gas bottle safe to work on: DO THIS BIT IN A WELL VENTILATED AREA. After opening the valve on top until it no longer hissed we used a large stillsons wrench to undo the valve from the top of the bottle. It's not as easy as it sounds as there is some sort of sealant on the thread so you may have to persuade the wrench with a lump hammer as we did!
Remove the valve from the gas bottle and fill your future stove with water: Now although the bottle was "empty" there was still plenty of gas in there, more than enough to ruin your day if you don't play it safe. The best way to stop your future stove from being a minor explosion is to fill the bottle with water and leave it overnight, better safe than sorry.
Mark out the door for your stove: Next, we marked out the door for the wood burning stove, we wanted to make sure it was big enough to put a decent sized log on the fire so we didn't have to keep feeding it with twigs every 5 minutes.
Cut your openings: For safety, we screwed the valve back in to the top of the stove and carefully cut the door out with the water still in the gas bottle using an angle grinder. At this point you have the absolute bare basics of your stove / logburner, I've seen people online using them like this as fire pits and patio heaters but of course for indoor use you need to put a bit more work in to the build.
For our design we wanted a proper door on the front of the wood burner rather than a gaping hole. Using the piece we cut out from the front of the gas bottle, we tack welded on some old hinges I had lying around and a screw in eye as a door handle
Of course, if you don't have a welder it’s just as easy to drill a few holes and bolt the door on to the hinges, or bribe someone to do the welding for you.
Air Intake and Ash Grate: Once the door was on we used the angle grinder to cut multiple slots into the bottom of the gas bottle so that the stove could draw in air when it is burning the firewood, but it also acts as a grate to let the ash fall out of the bottom of the log burner. We also drilled holes around the base of the gas bottle for additional air intakes.
Fit Exhaust: After that we welded on a piece of hollow tube fence post to act as the chimney for the smoke, ideally you want nothing smaller than 68mm to ensure that the smoke can vent out sufficiently. If you use 68mm it's also a common car exhaust pipe size so you can easily source fittings etc to make up a flue if necessary. Once the chimney was in place we drilled some holes around the very top of the chimney in the hope that it would help draw the smoke up the chimney faster.
Paint: We gave it a lick of black paint with some old black engine enamel lying around that was left over from our motorcycles, but a good cheap alternative is black BBQ spray paint.
As you can see the stove has no problem handling decent sized logs and really puts out a great amount of heat for its size, because rather than the heat being convected straight up the chimney and lost it is radiated through the mass of the metal stove instead. This means it is a much more efficient heater than an open fire and uses up far less fuel, thus creating less waste/mess. For us though the main benefit is that it is a lot safer to use with the small children around.
I am a great believer of evaluation and improvement. After using the stove for a couple of days the only thing we changed was to add additional intake holes all the way around the base of the gas bottle because after the fire had been burning all day and the ash started to block the bottom grate the stove would struggle to keep a strong flame with the door shut, the extra holes have solved this issue and we continue to use it every day as the only source of heat for the house with no problems at all. We made this stove last year and it kept our house cosy and warm all through the winter.
The final product in place: