Introduction: Simple Cinder Block Dual Burner Rocket Stove
This instructable will show you how to make a simple rocket stove out of common cinder blocks. I designed it to have 2 burners so you can use two small pans or one large griddle that covers both fires. I also designed it so you can make it from blocks that are readily available at Home Depot, and you will only have to modify one of the blocks.
I made my own grille grate out of steel flat bar that is also available from HD, after determining that cast iron grates for gas stoves were too expensive. All said i have less than $20 worth of materials in this stove and it cooks quite well.
6 - 8"x8"x16" common cinder blocks (there are 2 different styles of block at HD, you can use any combination of them- it doesn't matter)
1 - 3/4"x72" steel flat bar (i used 3/16" thick)
Step 1: Cut One Block
You will need to cut both ends off of one of the cinder blocks. This will create the burn chamber and allow the fire to enter the vertical stack. I used an angle grinder but gave up before cutting all the way through. I cracked the block while bashing out the concrete on one side- but the crack hasn't created any problems for me. If your block cracks, just push it together and move on.
Step 2: Arrange Your Blocks
Arrange your blocks as shown in the picture. The block you cut is shown with an arrow. Try as best as you can to level the area you're placing it on, this will help with keeping oil from pooling in your pan if it's unlevel. You can do minor leveling on sticks, which I did.
I've tried this without the top block, and found that the draft is much better having it this high. It also makes cooking more comfortable at this height.
Step 3: Construct a Grate (optional)
You'll need some kind of grate to place your cookware above the top of the brick. I chose to weld together some flat bar which is 3/4" wide- this seems like the perfect amount of distance above the brick to allow smoke and flames to exit the stove. Make sure this sits level as well. I welded tabs on 2 ends to anchor it and make sure it wouldn't slide off as I move the cookware around on the grate.
Step 4: Create an Air Intake (optional)
This step is optional but highly recommended. You can simply use a cut soup can, but they will burn out quickly. I found this piece of thin stainless steel angle iron in my garage. It was from a magnetic organizer that I never really used and it was pretty cheap on Amazon. Since it's stainless it has held up well to the heat and moisture.
It simply sits inside the burn chamber and holds up the sticks, so that there is always a channel underneath the fuel for fresh air to get inside the chimney. This way you can pack the brick pretty full with sticks and the fire won't starve for air.
Step 5: Light and Enjoy
Lighting the stove is fairly simple. I use a small propane torch, and start the burn by loading in the smallest diameter sticks I have. Once those are lit it's very easy to keep the fire going by adding sticks of whatever size you have that fit inside the cinder block. As the sticks burn down, push them further in as you load new fuel. With a little practice you will be able to keep the fire at a proper temperature for whatever you are cooking. I found it very easy to keep it at an appropriate temperature for making eggs and grilled cheese sandwiches.
One word of caution is, if you make the fire too big and hot there really isn't a control mechanism for dousing the fire except pulling sticks out of the burn chamber. I tried to see how badly I could over-fire it and i had 2' flames shooting out the top. This resulted in a brick cracking, so I think if you keep your fire at a reasonable temperature you should do just fine.
1 Person Made This Project!
- jleslie48 made it!
Question 11 months ago
We are making a cinder block rocket stove and were told that it is not safe because the blocks are not rated for fire. Since we have our supplies and want to build one, do you know of any substance that can be applied to the inside of the blocks that will protect the blocks from bursting? Most heat resistant paints are oil based and not rated for open flame. (It doesn't have to be paint). Thank you!
1 year ago
Thanks for posting this. I went with the 8-block version mentioned above.
If the fire starts burning too hot, just restrict the air intake? (turn the "end blocks" 90 degrees if you don't have anything to block the holes)
2 years ago on Step 5
very nice design. I added two additional cinder blocks, and now I don't need to break any of the cinder blocks, or need a piece of metal to make an airflow. In my update the air enters on one side, the wood on the other. the burn chamber is just a cavity made out of 4 cinder blocks and is not in any cinder block