❆Potbelly Stove With Chimney for Workshop❆

BR RRR ❆ ❆ ❆ it's cold inside! You have no idea what the real cold is like! Waking up in the cold with temperatures a few degrees above zero and being unable to move... Most people will never know how to freeze in the cold for long periods of time because they spend their lives in warm rooms in front of gadget screens.

Due to the new realities, energy has become more expensive (gas and electricity). I used to heat my workshop with electric heaters, but now, due to high energy prices, it has become impractical. So I decided to make a simple potbelly stove and a chimney by myself. I had an old wood-burning stove lying around for a long time and wanted to get rid of it for scrap. I also bought some metal pipes specifically for the chimney. Furthermore, I have a lot of metal parts, which came in handy for making this handy thing.

It took me about 2.5 months (200–250 hours of work) to build the stove and the chimney.

This stove is suitable not only for heating, but also for cooking and boiling water. It makes the kettle boil very quickly—in 7 to 10 minutes—and you can then make tea or coffee! It can also be used for heating your own greenhouse. Furthermore, it is easy to maintain, it is not expensive to make, and it can be transported. On top of all that, you get great pleasure from kindling the fire. Who doesn't like to see a live fire burning?

Materials:

❆ Metal flue pipes d=90/115/125/135 mm; 5 mm

❆ Metal pipes d=32 mm

❆ Corner metal 50×50 mm, 30×30 mm

❆ Metal case from an old potbelly stove

❆ Brake disc from a car 

❆ Anchor fasteners

❆ Sheet metal galvanized (0,7 mm)

❆ Self-tapping screws

❆ Screws

❆ Washers

❆ M10-1.50 Hex Cap Bolts / Screws

❆ M8-1.50 Hex Cap Bolts / Screws

❆ Stainless steel clamp

❆ Cotter pin

❆ Steel spring

❆ Metal rods

❆ Heat-resistant sealant for ovens (1500° C/2732 °F)

❆ Construction foam (90 °C/194° F)

❆ Silicone sealant (150° C/302° F)

❆ Mineral wool

❆ Chemical rust remover

Tools:

❆ Welding machine & electrodes for welding

❆ Angle grinder & abrasive discs, flap discs

❆ Belt grinder

❆ Hammer drill

❆ Drill machine

❆ Renovator saw multi tool kit

❆ Laser level

❆ Hammer

❆ Rubber mallet

❆ Welding magnets

❆ Riveter & rivets  

❆ Needle files for metal

❆ and other metalworking tools that can be found in any home workshop.

Safety: 

When working with metal, be sure to use protective equipment such as protective glasses, welding mask, noise protection headphones, respirator, gloves, special shoes, and protective clothing!

These are some sketches and calculations made during the development and realization of the project.

The first thing I did was make the chimney. For this, I used pipes of two different diameters: 135 mm and 115 mm. Due to the fact that the pipes were covered with rust, and in some places with paint, I had to pre-treat them with a belt sander. I also used an angle grinder with emery and abrasive wheels. My house has two levels, and the workshop is on the bottom floor. Therefore, I led the chimney through the ceiling in the workshop to the second level, and then it goes to the roof through the attic.

One of the pipes was the longest, so I used it for the second level of the chimney. It consisted of two sections of pipes of different diameters, welded together. There were small defects on the pipe joints, so they had to be welded with a welding machine. I patched some small holes using metal plates for this. The total length of the pipe was approximately 4 m. Its first stage, with a diameter of 115 mm, has a length of 2.7 m. The second stage, with a diameter of 85 mm, has a length of approximately 1.34 m. I cut off the edges of the pipe with a grinder. Thus, the total length was 4.06 m.

I also processed another pipe with a diameter of 115 mm and a length of about 1.8 m along the edges, cutting off excess metal with a grinder. I prepared it for the first level, which will be directly connected to the stove. And I left the third pipe with a diameter of 135 mm and a length of about 1.2 m for making connections between chimneys. As a result, the total height of the chimney turned out to be about 5.4 m. This means that such a long pipe is more than sufficient to generate draft, allowing smoke to easily pass through the chimney. Additionally, I treated all pipes on the outside with a chemical anti-rust agent. This will prevent further corrosion of the metal and extend the life of the chimney.

Because the metal chimney pipes are very heavy, I decided to divide them into several parts. And in order to connect them together, I came up with a kind of connector made from sections of larger-diameter pipes. This connection solves the problems of condensation and smoke escape. It is practically airtight and easy to mount and dismount for later use. The use of a thick wall pipe (approx. 5 mm) increases the service life of the chimney when compared to ordinary chimneys sold in shops. In addition, they are expensive! )

In the process, I had the idea of using the leftover 135 mm diameter pipe as an additional heat sink for the chimney. I used a grinder to cut four 250 mm segments (rings). A little tip for cutting pipes with a grinder: if you do not have a chop saw, you can cut the pipe evenly using a piece of paper and a marker or chalk. Tight poster paper will work. The flat edge of the paper should be wrapped around the pipe, secured with paper tape, and then you can draw the cut pattern around the circumference of the pipe with a marker. I used a large grinder with a 230 mm cutting wheel. It's easier and quicker to work with these tools!

The cut rings fit loosely into the smaller diameter pipe, so I used metal rods from welding electrodes with diameters of 4 and 5 mm. I welded three rods per section, distributing them proportionally to the diameter of the pipe. I pushed the connection rings on both sides of the pipe inside. The rings on both sides of the chimney come out in relation to the main chimney pipe. On the lower side, where the stove connects, this gap is 100 mm, and on the upper side, 150 mm. I spread the other two segments at the same distance. After that, I welded all the pipe segments together. To ensure a better seal and not use too many welding electrodes at the same time, I made small inserts from welding rods. After tacking one end with a weld, I hammered the rest into the gap between the pipes. I used three pieces of these rods each. After this preparation, you can safely weld the pipe joint using 4-5 mm diameter electrodes. Once you have finished welding, you need to machine the metal with a grinder.

You can use more rings as a radiator to ensure the best heat dissipation. In addition, this double chimney pipe has a higher degree of fire safety!

In order to be able to carry out a stepped installation of the chimney, I made a special holder. It can be installed in the ceiling between the floors of the building. First, you need to cut the metal corners to size. It is necessary to take into account the diameter of the pipe in order to make such a design. This holder resembles the Roman numeral two (II). In order to additionally fix it to concrete, I drilled four holes (11 mm) for 10 mm anchor bolts. After welding the frame of the holder, it must be fixed to the chimney pipe. Using a welding machine, it must be welded on both sides so that it supports the total weight of the chimney. And this, as you know, is a lot! Therefore, welded seams must be of high quality. After finishing the work, I additionally processed the metal to remove rust.

At this stage, you need to prepare the upper chimney for connection with the lower one. To do this, cut a ring 100 mm long from a pipe with a diameter of 135 mm. You also need to prepare three metal rods about 95 mm long. By welding, the ring is fixed at a distance of 150 mm from the chimney outlet. Just as before, you need to put semicircular rods into the gap between the pipes and weld the connection. They can be slightly flattened with a hammer to facilitate installation. Due to the fact that the pipe is long and heavy, for a better installation, I made two handles from the rebar. With their help, it will be easier to install and adjust the chimney.

To fix the chimney to the wall, you need to make a special mount in the form of a console. You can buy such a bracket, but due to the fact that I have a lot of leftover metal corners, I made it myself. For its manufacture, a corner of 50×50 mm is needed. First, you need to cut the corners according to the given sizes. In order for the chimney to be moved during installation, I made the console design adjustable. To do this, you need to drill a hole with a drill having a diameter of 10 mm and cut the metal between them. Thanks to these cutouts, it will be possible to move structural elements, as on a sled. Using a welding machine, you need to fix two corners, creating an L-shaped element, as you can see in the photographs. For greater structural strength, I added two metal triangles, which I also welded. On the main frame, I made six holes with an 11 mm drill. These holes are needed to attach the console to the wall of the building. In order to secure the chimney, I used a U-shaped connecting strip. M8 (M10) bolts and nuts, as well as additional washers, were used to connect the console elements to each other. To prevent further corrosion of the metal, I treated the entire structure with a chemical rust preventative. You can also color it if you like. Due to the fact that winter was approaching and there was not enough time to complete the project, I figured that the painting could be left for later. In addition, the chimney is mounted indoors.

The chimney is probably the most difficult and important part of this project. No stove or fireplace will work without a good chimney draft! Therefore, it was essential for me to finish the chimney, and then work on the stove itself. In addition, the weather was getting worse, and installing a chimney on the roof in bad weather is not the best idea. First, I marked out and made a hole in the ceiling of the workshop. In this case, it was necessary to take into account the exit of the pipe to the roof. According to fire safety standards, the chimney must be at a certain distance from the wooden elements of the roof! Before that, I treated several times the wooden beams of the roof with a special agent for fire safety. After I made a hole in the concrete ceiling with a puncher and cut off the excess reinforcement, I immediately set up a laser level to mark the exit of the chimney in the roof of the house. For greater rigidity of the reinforced concrete ceiling, I fixed additional connections from metal reinforcement by welding.

Next, I installed the first stage of the chimney pipe through the ceiling in the workshop and secured it with anchor bolts to the concrete. Before that, I adjusted the vertical position of the pipe using a laser level. In order to install the second level of the chimney, you must first make a hole in the roof. To do this, I used a drill, with which I drilled many holes, and only after that did I cut the opening for the chimney using the renovator. (30 cm x 30 cm).

Due to the fact that my house is two stories and therefore very high, getting to the roof surface is quite difficult. Therefore, I decided to lift the chimney mushroom (you will find a description of its manufacture below) with a rope to the roof and fix it with bolts from the inside. This elegant engineering solution was a success! My friend helped me with this, pulling the rope from the inside. After we raised the chimney and fixed it, we additionally used mounting foam to seal it and fix it to the roof surface. I chose the most heat-resistant building foam; it can withstand temperatures up to 90 °C (194 °F). All other technological holes were filled with silicone for the best seal against precipitation.

After that, we lifted the chimney and put it directly into the hole in the roof. It protrudes about 0.5 m above the roof. And the height of the chimney itself is 1.5 m. The gap between the pipes was sealed with mineral wool. The gap between the pipe and the concrete ceiling was also closed with mineral wool. After installing the chimney and adjusting it, I finally fixed it to the console, which is installed on the wall of the building. The connection between the down tube and the top tube was sealed with a special thermal paste that can withstand temperatures up to 1500 °C/2732 °F. After that, I secured it with a stainless steel clamp. Using a clamp that I made specifically for this project. In order to prevent condensation on the chimney, I used mineral wool as thermal insulation. Additionally, it can be covered with aluminium foil for better insulation.

This part of the chimney is very important because the connection between the roof and the chimney must be airtight. It protects the house from bad weather and the external environment. As a base, I used a metal square tube (155 mm) from my stock. I also found a round pipe (d 135 mm) from the same material. In order to connect a round pipe with a square one, you need to flatten the square pipe with a hammer, setting it on a piece of metal pipe of the required diameter (d 135 mm). Next, I cut the bottom of the square tube and bent the petals at a 30-degree angle. This is the angle of the roof slope. That is, when installing a chimney, it will be vertical relative to the house. Next, I cut out and made a metal platform, which will be the basis for attaching the chimney. The connection of the metal parts was made with rivets and sealed with silicone. In order to wave the sheet metal of the roof surface, I used a rubber mallet and a sample of the roof covering.

To fix the chimney without climbing onto the roof itself, you need to prepare a mount for installation in advance. For these purposes, long 80 mm bolts (M8) were used, which must be welded to the base of the chimney. Due to the fact that the metal is very thin, I used additional washers that are inserted into the bolts. After that, using a DC welding machine and the thinnest electrodes with a diameter of 1.6 mm, the bolts were welded to the base. They also need to be sealed with silicone.

This is the final stage of the chimney assembly. Having decided on the height of the protruding part of the chimney above the roof (1.5 m), I connected the two pipes based on this size. After that, I prepared the chimney cap by rounding it off a bit with a rubber mallet. With the help of three metal strips, I fixed it to the pipe using rivets. The chimney cap (umbrella) protects the chimney from precipitation and foreign objects entering the chimney. After that, I started making the deflector. The deflector cap is needed in order to regulate the draught in the chimney and protect it from the wind flow. To make the ring, I used an aluminium plate, which I fixed to the pipe with universal mounting fasteners for drywall construction. The assembly of this chimney made the most use of aluminium rivets instead of using self-tapping screws that rust over time!

At this final stage of the chimney assembly, you need to connect the pipes by drilling holes for the rivets and installing them in sequence using a riveter. You also need to seal the connection with silicone. The top of the chimney is ready! In order to lift it to the roof of the house, I used an ordinary rope with an unusual knot. I tied the rope around the chimney with an intricate knot that I made myself. One end of the rope is used to climb onto the roof, while the other small end of the rope can be pulled and the entire knot released. This is what ingenuity leads to when there are no other possibilities!

I had an old potbelly stove lying around that I was going to throw away. She worked for many years in my old workshop. Aside from the rust, her general condition was not the best. I decided to restore it and give it a new life! The dimensions of the furnace are as follows: 73 cm in length, 36 cm in width, and 27 cm in height. The furnace body had cracks in the metal and was partially deformed. First, I treated all the metal with an anti-rust agent.

In order to increase the efficiency (performance) of the potbelly stove, I thought to make an additional chamber for the secondary combustion cycle for gases. The remnants of metal profiles with thick walls were used as a body for an additional combustion chamber. I made a U-shape, which I welded to the inner surface of the stove body. In order for the carbon monoxide combustion process to work properly, it must be fed with heated, fresh air. To do this, I made a 12 mm hole at the bottom of the combustion chamber. In order for the air to have time to heat up to a high temperature, I welded two corners on the back of the stove, thus ensuring the air supply from below. From above, I closed this channel with a small metal plate. This idea with a technological air supply hole will also serve to drain the water (drainage) in the event of an accumulation of condensate in the chimney. At the end, you will see that after installing the stove, I made a slight slope so that the water drains into the bucket. Thus, moisture will not accumulate inside the stove!

The potbelly stove had holes so that you could put a cauldron or pan into it to heat food. I decided to close this hole so that smoke would not escape through it. For this, I used an old brake disc from a car that was just the right size. First, I cleaned it with a grinder. I then welded all the holes. Brake disc metal is difficult to weld because it is an alloy that contains cast iron (special electrodes can be used). Then I welded the disc to the main surface of the furnace. The thickness of the disc metal is about 7 mm, which will positively affect the overall thermodynamics of the stove.

Due to the fact that the potbelly stove was already in operation, its metal case needed repair in some places. I welded a few cracks by adding small metal plates. I also straightened the grate and welded in additional pieces of rebar. With the help of a car jack, the swollen parts of the metal case were also straightened. All burrs and metal residues after welding were processed by a grinder.

The old potbelly stove legs were good for nothing, so I cut them off and made new ones. I used old metal pipes with a diameter of 35 mm. In order for the legs to become adjustable, you need a set of four screws (M8/60 mm) and nuts, as well as washers for the diameter of the pipes. Using welding electrodes on d 1. 6 mm, you need to weld the nuts to the washers, and then to the pipes. As a sole for the feet, I used pieces of 50 x 50 mm corners, to which I fastened the screws. In order for the legs not to slide on the floor surface, I made small bulges by welding. After that, the pipes were welded to the furnace body. The result is legs that can be extended and adjusted at intervals of 40 mm.

To increase the heat transfer of the furnace, I attached radiators to it using a welding machine. I made radiators from 30×30 mm corners, which were previously welded together in two pieces in the shape of the letter T. I made 26 of these radiators, each 31 cm long. Due to this system of radiators, the total heat transfer area of ​​the furnace increases. At the same time, this gives a small increase in the total heat capacity of the heater. The gaps between the radiators allow free circulation of air, which heats the room faster due to convection.

The damper for the chimney is a very important detail of the project! With the help of a damper, it is possible to regulate the draught of the chimney and at the same time keep the heat inside the combustion chamber of the furnace. A very essential point is that I decided to install it in the body of the furnace, below the connection of the main chimney pipe. This is done to make cleaning the chimney easier (something that many craftsmen overlook) ! In order for the connection of the chimneys to be the most hermetically sealed, I inserted an additional ring made of a larger diameter pipe into the chimney pipe of the potbelly stove. Thus, only one hole in the outer pipe is required for the damper adjustment knob. This appeared to be the most elegant solution because it solves the condensate and smoke problems as well.

So, in order to make a damper, you need a metal rod (d 10 = mm), preferably in a square shape. You also require a piece of pipe (d = 16 mm), a metal plate along the inner diameter of the pipe with a thickness of at least 3 mm, a metal washer, and a steel spring of a suitable diameter. You will also need a small cotter pin so that the handle does not come out of the mechanism. The metal plate must be cut with a grinder to a diameter smaller than the chimney (d95mm). The 1/4 surface segment is also removed. This is done so that even when the damper is closed, smoke passes through the chimney. This is very important because it could save your life! Carbon monoxide poisoning is very dangerous for human health! I recommend installing a sensor with an alarm that reacts to CO gas!

After giving the damper the desired shape, a pipe is welded to the damper. It needs to be flattened with a hammer. The damper handle is made from a metal rod. The end of the rod must be bent by about 90 degrees. From the other end, using a needle file, you need to remove a piece of metal and drill a small hole where the cotter pin will be inserted. On the side of the handle, a washer is welded. If you use a round rod and not a square one, as in my case, then its surface, which is inserted into the damper, needs to be slightly thickened by welding. The damper must then be tested for direct operation in the chimney. Due to the tension of the steel spring, the damper will be fixed in the position in which it was installed.

Finally, the most long-awaited part of the project! Before installing the potbelly stove in its place, I added a metal clamp in order to secure the stove to the chimney. For tightness, you can add a little high-temperature thermal insulation paste. After that, I lifted the potbelly stove with a jack and installed bricks under the legs. Then I adjusted the legs so that the oven body was slightly tilted back. This is done so that water and accumulated condensate flow out through the vent into a special container located at the back of the oven. I put bricks on top of the potbelly stove in order to increase the heat capacity. If food or water needs to be heated, the bricks can be easily removed. After lighting the fire, I immediately noticed that this stove has a very high smoke draft! Therefore, after the fire flares up, the damper must be partially closed to retain heat. It is very important for me that I can now work in my workshop even during the cold season. If you properly kindle and maintain a fire, the cost of firewood will be small. Such heating is much more profitable than electric or gas. Now I feel more independent of the events of the world. I have a small garden around the house, so some firewood is absolutely free. I also use leftover cardboard and paper to start a fire.

Thank you very much for your attention!