A fire pit spark arrester is comprised of a square metal or tube steel frame that is strung with steel wire mesh to prevent sparks and embers from becoming airborne and creating a fire hazard. The spark arrester is elevated from the top of the fire pit in order to provide access for lighting and placing logs or coals. It is held in position either by a metal supporting system or suspended from overhead and the arrester may have a chimney flue or cap depending on the overhead conditions. An open-air spark arrester will have a cap and an under roof spark arrester will have a chimney flue.
Begin by measuring the fire pit diameter or the square width dimensions and making a materials list. The metal frame can be angle iron or tube steel and the size of this metal will depend on the size of the pit. A good rule is 1” steel for every 48” of width. The steel wire mesh should be 3/16” maximum and the gauge of the mesh should be no less than #6 in order to prevent heat deterioration.
For a square or rectangular frame cut (4) pieces of 1” x 1” angle iron to the lengths of the sides and place them on a flat surface in the desired configuration. Check the dimensions and weld the pieces at the corners. Allow the welds to cool and grind any excess to achieve a uniform surface weld. If the frame is larger than 36” across at any point weld one or more additional pieces of 3/16” thick flat iron struts to span the opening and support the wire mesh. These struts should be a maximum of 48” apart. For a frame with an overall dimension of 60” a strut will be needed across the frame at the center point. Prime the steel frame with a high heat metal primer and set the frame aside.
For a tube steel frame use minimum 1” x 1” x 3/16” thick square or round tubing. For a square or rectangular configuration assemble the frame using the same procedure as applied for the angle iron frame assembly. For a round or circular steel frame use minimum 3/32” x 1” tubing and make the circular frame using a steel tubing bender. Weld the ends of the steel tubing and allow the welds to cool. Grind any excess and prime the frame with a high heat metal primer.
To screen the fire pit spark arrester place the frame on a flat surface and lay the screen across the frame allowing a minimum of 1” overhang all around. The screen can be attached to the frame using pan-head sheet metal screws at 4” apart or by tack welding the screen to the frame. Be sure to pre drill for the sheet metal screws. Trim any excess screen and paint the spark arrester frame with (2) coats of high heat resistant paint using the desired color.
Affix the frame in position either by attaching to a metal support system or by suspending it from an overhead structure such as a ceiling or roof beam. The fire pit spark arrester may be suspended using steel chain and eye bolts or other metal systems that employ flat steel or tube steel. Install the chimney flue riser or spark arrestor cap.