DIY Cheap Rocket Stove(efficient With Insulation)

Hello, my name is Astute, and I’m a high school student. Recently, while watching youtube I came across Rocket Stove—which is basically a more efficient alternative to a traditional wood stove, and so today we will be making a cheap rocket stove at a low cost using just tin cans and perlite as insulation! It’s simple, efficient and portable and can be used for cooking off-grid or even as a heater to keep you warm in winter or any cold day.

If you're just getting started, don't worry; I've attempted to keep this instructable as basic yet informative as possible, with clear and easy-to-follow instructions, making it appropriate for beginners as well!

Here is a simple lecture on why it is efficient:(basic level)

So in a regular open stove, its design allows air to flow in from all directions, which means the heat generated by the fire also moves out in all directions instead of being directed efficiently. As a result, a lot of energy is lost/wasted, and you need more wood to maintain a high temperature. But in rocket stove, thanks to the L-shaped design and insulation, the burning wood releases hot gases, and since hot air naturally rises, it can’t escape sideways. Instead, it's forced to move only upwards, which means less chance of it escaping and in turn leads to better combustion, and higher efficiency, allowing you to cook faster while using less fuel.

Lets start!

1. Soup cans (1 large + 1 medium for the body, 1 small for fire tunnel)
2. Perlite (insulation; alternatives: ceramic wool)
3. Refractory cement (for sealing)
4. Metal sheet (for fire tunnel floor)
5. 3 long screws or bolts ( makeshift pot stand; alternative: metal grate/grill)
6. Sandpaper (to smooth out or remove imperfections)
7. Heat Resistant Paint (to paint the stove)
8. Small twigs and dry sticks (fuel source)
9. Other tools such as Dremel, File, Drill, Marker

I created a Fusion 360 model of the design, and the images above show both the cross-section(illustrated and raw) and top view. These visuals should help you easily understand how all the components fit together and their respective placements within the structure.

Before we begin assembling the rocket stove, we need to carefully prepare the cans, as shown in the reference image.

Steps:

1. Remove the Lids:
2. For the small can, using a dremel,
3. Cut one side open entirely and on the other side cut it into a small plate only one side still hanging on.(refer image)
4. Then bend this into a support piece/foot.(refer image)
5. For the medium and large cans, remove the lid from only one side, leaving the other side intact.
6. Smooth the Edges:
7. The cut edges will be sharp, so use a metal file or sandpaper to smooth them out. This will make handling safer and ensure a better fit when assembling the stove.

As seen in the cross-section image, the small can needs to be attached to the other two with proper alignment.

For that we need make holes

1. Use the small can lid as a reference to mark the cutout on the medium and large cans, ensuring precise placement
2. Now carefully using a dremel cut along the markings to get a result similar to the image
3. Also cut a small piece of metal plate or prepare one from another can to make the divider
4. It should be of a bit bigger than length of the small can and of same or slightly smaller width(refer image)
5. On the small can at one end make a notch for this plate to slide in and lock onto.(refer image)

Position the Medium Can:

1. Place the medium can perfectly centered inside the large can.
2. Ensure that the holes in both cans are properly aligned.

Insert the Small Can:

1. Carefully insert the small can through the openings in both the large and medium cans.
2. Adjust its positioning to match the layout shown in the diagram.
3. If necessary, carefully enlarge the cutouts slightly to achieve a precise fit.

Slide in the metal plate:

1. Slide the divider plate into the small can and align it properly with the help of the notch.

Now that the medium container is in place, we can move on to insulation.

1. Cover the medium can.
2. Grab the lid and place it on top of the medium container, sealing it off as shown above, to ensure that the perlite does not fall into the chamber.
3. Fill the gap with perlite.
4. Slowly pour perlite into the gap between the medium and large cans.
5. Give the huge container a few gentle knocks to help the perlite settle evenly, or you may even use a screwdriver or a rod to squeeze it in, making sure to leave a little gap on top for a layer of cement.

Since we are using refractory cement, which is basically pre-mixed concrete that only needs water to activate, follow these steps:

1. Take a Small Container – We don’t need a large batch, so use a small mixing container.
2. Add Refractory Cement – Pour in the required amount.
3. Gradually Add Water – Slowly mix in water while stirring continuously.
4. Adjust Consistency – Aim for a flowing but paste-like texture—not too watery, but smooth enough to spread easily.

Now Cementing time

Applying the Cement

Before jumping into cementing, take a good look at the image to see exactly where the cement needs to go. You'll be applying it around the perlite insulation, inside the combustion chamber, and also setting up a pot stand.

1. Seal the Perlite – Spread a layer of cement over the perlite insulation to seal it off and feel free it even it out
2. Reinforce the Chamber – Coat the inside of the combustion chamber with a thin layer of cement for adding structural support and weight so that it doesn't topple over.
3. Set Up the Pot Stand – Stick three nails or screws around the top of the chamber (like in the image) to support your cooking pot or you can also use wire mesh or make a grill instead based on your liking.
4. Let It Dry – Now, let it sit and fully cure for about 1 Day before the next step.

Okay, now that the cement has completely dried, it's time to clean everything up before painting.

Smoothing the surface.

Before we begin painting, get some sandpaper and lightly sand down any rough places or uneven edges. You don't need to go overboard; just enough to remove any jagged parts and smooth the surface.

Choosing the Right Paint

Because this stove will be subjected to high temperatures, you must select high-heat resistant paint that will not burn, peel or emit harmful odours when exposed to flames. Standard paint simply won't cut it. Look for spray paints marked "high-temperature" or "stove paint."

When painting, just take it easy—go for multiple light coats instead of one heavy layer to avoid drips and uneven coverage. Also, make sure you're doing this in a well-ventilated area or outdoors to stay safe from any fumes.

Now after all this you should gotten a pretty similar look like above image.

I used small twigs as fuel, but you can honestly go for bigger twigs or even other stuff if you want.

Starting the fire is pretty simple, but here’s a basic rundown:

Take your twigs and place them in the upper portion of the side inlet. Use a lighter or torch to ignite them. Make sure not to block the lower half—that’s where the air flows in.

Congrats on making this far here is what we have made in concise a DIY efficient and portable stove which can be used for cooking off the grid such as boiled eggs ,boiling water but also for maybe keeping your hands warm too in this climate

Anyways, here are my optional upgrade suggestions:

1. You could maybe drill holes at the top and bottom to create a hybrid rocket stove/wood gasifier system, resulting in a cleaner, more efficient burn with minimal smoke.
2. As I said earlier you could replace the screw pot stand with a grill or wire mesh which I couldn't sadly.
3. In total it is your build so feel free to personalize it according to either what you have lying around and what you desire it to be like.

If you've built one yourself, share it below and inspire others!

With that said, Happy camping, and Happy building!"