Build Your Own “smokeless” Campfire
Fire pits are often considered an attractive part of outdoor spaces, but sometimes the smoke they create is not very attractive. Whether the lingering smell on your coat or in your hair is unpleasant, or you find yourself the type of person who always seems to sit where the wind blows the smoke away, reducing it can improve the quality of your evening by the fire. . While there is no such thing as a completely smokeless fire, so-called “smokeless” bonfires use a dual-chamber combustion system that produces significantly less smoke.
How does a smokeless fire work?
The job of a smokeless fire pit is to circulate air through a double-walled container in which to start a fire. This simple and ingenious engineering technique, pioneered by the people of the Dakotas , can be replicated in our modern fire pit designs, either by modifying an existing backyard pit or building a new one.
The air is heated as it passes through the outer wall, and at this higher temperature, more fuel is burned, resulting in less residue, ash, and smoke. The downside is that a hotter fire tends to send heat up faster than out, so it doesn’t have as much radiant heat as a traditional campfire; but it still has dancing flames and warm light, and you will still feel the heat from the fire.
What do you need to make a smokeless fire?
For this project you will need:
- Drill with a drill for metal
- Either an existing metal ring fire pit or a 20L and 16L pot (plus a lid for a 20L pot)
- Jigsaw with metal blade
- A sturdy pair of metal shears or a grinder (to build a new smokeless fire pit without a stone structure)
- Metal file (to dull the edges of holes and cut out metal parts)
- Heavy pair of metal work gloves
- Protective glasses
- Ear protection
How to retrofit an existing traditional fire pit
For your existing pit, remove the metal ring from the pit and widen the base so that it rests about an inch from the outside of the metal fire ring, leaving enough room for your finger to fit between the outer wall of your pit and the grate. the ring is enough to allow air to pass around it from the outside.
After you have laid the first layer of stone or brick, you will need to create space for air to flow into the gap. Some people spread their rocks at the base to make an air intake about every foot or so around the circumference of your hole. If you are using bricks, you can use half a brick with space on each side of it through every second or third brick. You can then repair the outside wall of your fire pit without any gaps.
Next you need to drill holes in the fire ring. Use a drill and a metal bit to drill a hole about every foot, about an inch from the top edge of the metal ring. You must use your protective gear for this part to prevent metal shards. Use a file to smooth the edges of the drilled holes and remove any remaining nicks. Put the ring back in the fire pit and you’re done.
How to build a new smokeless fire pit
To build a new metal smokeless fire pit, take the lid of a 20 liter pot and use the bottom of the smaller pot to draw a circle in the center of the underside of the lid with a permanent marker. Put on protective gear and use a grinder with a cut-off blade, a drill, and a metal-bladed electric jigsaw (or a drill and metal shears) to cut out the middle of the larger pot’s lid. Use a file to smooth the edges of your hole and your smaller pot should fit into the lid of the larger pot leaving about an inch gap between them.
Then drill holes every three inches or so, an inch from the top of the smaller pot and an inch from the bottom of the larger pot. Use your metal file to remove any nicks and smooth out the edges of the holes. Then when you connect the two cauldrons you will have a small smokeless stove. Make sure that when you use your stove, you don’t place it on a surface that is vulnerable to heat so you don’t start a fire outside of your pit.
This method will work with any pair of containers with the same size ratio, such as a 20 to 16 liter ratio. For a larger model, metal trash cans are also suitable.