Introduction: Concrete Fire Pit

Picture of Concrete Fire Pit

What inspired me?

Well this was a project that I completed in college. We all made cube like structures to test different concretes. I decided not to waste them and thought of a practical use for mine. I decided to make it into a basic fire pit.

You will need;

- Concrete mix

- Water

- stirring stick

- Ply wood

- Band Saw

- File and sand paper

- Hot glue

- 7cm diameter card tube

- pen and ruler

- tri square

Step 1: The Mould

Picture of The Mould

Step one - The mould

The mould is actually easy as easy as moulds get I mean. This mould consists of only 5 pieces of ply wood, all the same size. On top of this, you will need a card tube that is 70mm or a tube that is in-between 60mm and 85mm. Any bigger the concrete will get damaged easily.

Use your pen to draw out five squares that are 150mm wide and 150mm high. This is a perfect night. It allows you to add different bits to the fire without increasing the possibility of burning yourself.

Using your saw, begin to cut out the pieces. I used a band saw to get a straight cut. This also meant that I could get all pieces the exact same size.

Use the sand paper to sand the edges. This ensures you won't cut yourself on the burs left after cutting the plywood.

Step 2: Gluing the Ply

Picture of Gluing the Ply

Step two - Gluing the Ply

Place the pieces where they go just to make sure you know exactly where they go. When you are sure, begin to add blobs of hot glue to the sides and start sticking the pieces together. Remember not to get any on the insides as it will mess with the end products surface ending up with uneven sides. Do not glue the tube inside!

Step 3: Adding the Concrete

Picture of Adding the Concrete

Step three - Adding the concrete

Before you mix in the water with the two dry materials, it's best to mix the cement and the sand. First, place about 700g in the container. Add about 400g - 500of sand and then use the fork to mix them together. Mix until the mix goes light grey.

Its now time to add the water. Never put in all of the water in one go. You will need to add about 50ml then stir. Complete this step until the mix becomes like cookie dough. If you add too much or too little you will end up with a weak mix. Place the tube in the centre of the mould.

Begin to spoon the mixture into the mould. Use the dowel or spoon to ensure the mix gets into the corners. Keep spooning the mixture in until it is filled. Vibrate the mould onto the table until the surface becomes even.

When the concrete has set (leave for about two days) begin to take off the mould using a chisel then run under warm water to get the tube out.

Step 4: Finished!

Picture of Finished!

Finished!

Concrete does not harden. However it goes through a chemical process known as curing. The concrete sets within a few hours but it takes an entire 28 days to reach its maximum strength.

Well done, easy wasn't it? Thank you much for reading and I really hope you liked this project. When the holidays are over I won't be able to complete projects as much but ill ensure the ones I do publish will be amazing! Please follow and favourite for more 5 minute summer DIY Projects!

Comments

sokamiwohali (author)2016-08-21

Just a thought... I didn't see anything in the 'Ible about a breather hole for the fire. Perhaps you might add a breather hole or a few at the base? ☺️☺️good project.

zaclewis98 (author)sokamiwohali2016-08-21

I actually made a mould like this one, and added a pvc pipe that was 3/4 and placed this between the tube and the ply wood. However, it go stuck and when I tried to get it out, the concrete cracked

fdominguez (author)zaclewis982016-08-28

Maybe try it with pvc wrapped in cardboard, like a paper towel tube?

JustinC86 (author)fdominguez2017-05-02

Maybe spray with some mold release?

jtobako (author)2017-04-08

No vents in the bottom for air?

Jobar007 (author)2016-08-22

Concrete is porous and absorbs moisture from the air and from the ground if stored outside on the ground. Water, when heated, likes to expand, sometimes rapidly. To extend the life of this little fire pit, you would probably want to store it in a dry place, off the ground. It would probably be a good idea to leave it out during a sunny day before use as well to help drive off any moisture in the pit.

geoffdscott (author)Jobar0072017-02-19

Jobar007 is absolutely right. If there is moisture in the concrete, the heat from the fire will at least cause a big crack. I was at a BBQ once where the host had made their own brick and concrete slab BBQ. After about 2 hours, one of the slabs exploded, showering us with the remaining coals and ash. It wasn't a powerful explosion (I was standing right next to it), it just wrecked the BBQ and singed me a bit. As Jobar007 says. it will need many hours of being very warm before first use and will need to be kept dry from then on.

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