This style of firepit is similar to a forge in that the oxygen that is fed into the center of the pit greatly increases the temp. and rate of burning – which means it’ll have the capacity to burn a larger amount of material in a short period of time. This is useful for burning paper trash, personal documents, wood scraps, etc. No more need for a paper-shredder and you get to enjoy your fire pit (play with fire) at the same time!!!
- Flagstone or other suitable “flat” paver material for border and, if wanted, surrounding perimeter for more of a patio look
- Cinder blocks for walls below ground level of firepit
- Gravel material for filler in and behind cinder blocks, as well as in between patio stones in order to lock them in place to prevent movement
- Gas pipe (1/2 inch diameter) – one at least a 6 ft. long and another approx. 6-8 in. depending on the depth of the cinder blocks and thickness of the flagstones or other paver material
- 2- Gas pipe collars (90 deg.) to connect the gas pipes
- Various digging tools: shovel, spade, wheelbarrow, etc… gloves, level, tape measure…also, hammer, chisel, eye protection (to re-shape flagstones if necessary)
Find an open location far enough away from buildings to be suitable for open burning. Next, determine the diameter (full distance across) of the pit opening you prefer. Remember to add the width of a cinder block (7.5″) on both sides of the pit of the pit’s circular opening diameter when digging. Before digging, take and set up the cinder blocks to pre-figure the circular pattern that the pit walls to determine how many blocks will be required to form the circular pattern of the pit. For ease of arranging the blocks to form the actual in-ground pit opening after digging, dig roughly 4 inches out beyond the determined diameter (actual pit diameter plus width of 2 blocks (2 x 7.5″ = 15″) and 4 in. outside of the outer block perimeter. (If your pit diameter is 5 ft wide, your digging diameter will need to be approx 7 ft.)
After roughly digging the full circle, dig a trench wide and deep enough to lay the gas pipe (one end will begin 1/3 the way across the circle (centered) and extend 3-4 feet behind (or beyond) the fire pit wall. (In our project we used a broken block turned on its side as an opening for the gas pipe to pass thru to extend behind the pit wall.). Begin building the fire pit wall with the cinder blocks using a level and tape measure to properly set the blocks and create the pit wall. Leave a space between two of the blocks to allow for gas pipe below the flagstones. Once the cinder blocks are level and in position, begin placing gravel in the holes of the blocks as well as between and behind them to act as a barrier to prevent the surrounding soil from washing into the fire pit. Next, set the flagstones on top of the blocks and allow the stones to overlap each block approx. 2 inches to semi-hide them for appearance-sake.
After the gas pipe is assembled and set in place, fill in and around it with gravel. (Make sure the top collar stays even level-wise with the flagstones that surround it to avoid a tripping hazard.). Once the flagstones are in place on top of the cinder block wall, your ready to use the fire pit.
Before using oxygen with the gas pipe, use the proper attachments to create a seal between the upper gas pipe collar and the nozzle of the oxygen source to ensure having the continual high pressure necessary to effectively feed the fire. (Caution: keep oxygen source (oxygen tank or compressor itself) at least 10-12 feet away from the point of connection between collar and nozzle.)
The fire pit we constructed is somewhat over-sized because we usually have a lot of things to burn at any given time.