- Basic hand tools
- Concrete trowel
- Miter saw
- Mixing tub
- Table saw
- Trim nailer
- Wire cutters
- Burner kit
- Quikrete Countertop Mix
Project step-by-step (21)
How to make a propane fire pit: The burner kit
The first step in how to make a propane fire pit is to find the propane burner. The burner runs on propane and will last six to 12 hours on a 20-lb. tank. The fire it produces will warm your hands and take the chill off, but it doesn’t throw off enough heat to keep you warm on a cold night the way a bonfire would. The propane tank is stored under the table, but you can bury a line and hook it up to your home’s natural gas if you wish. The beauty of this projects is that it’s basically a table with a fire pit in middle.
Building a Table: Taper the feet
When building a propane fire pit, start with the base that will house the burner. When building a table cut the posts (A) to length on a miter saw (see Cutting List). Taper the bottom edges about 1/2 in. up with a miter saw. The tapered edges won’t tear out when the table is slid around, and they’ll look better when it’s sitting on uneven ground.
Cut and assemble the frames
Cut three 8-ft. 2x4s in half to create six 4-footers. Rip down five of the six into 1-1/2-in. x 1-1/2-in. boards. From these, cut the frame sides (B) and the front frame bottom (E). The other frame parts (C and D) are cut from full 2x4s.
Secure the frame sides to the tops and bottoms with two 2-1/2-in. screws. Connect the smaller front frame bottom with one screw in each side. Drill 1/8-in. holes through the frame sides before you install the screws.
Attach the side frames to the posts
Drill three holes through the sides of the side frames. Lay the frames flat on your work surface. Align the frames and posts flush at the top, and secure the frames to the posts with three 2-1/2-in. screws. Take note of the wood grain on the posts and place the most attractive sides facing out.
Attach the front and back frames
Set the side frames and posts upside down. Line up the inside corner of the front and back frames with the inside corner of the posts and secure them with three 2-1/2-in. screws driven through predrilled holes.
Install the angle braces
Cut the angle braces (H) from 1-1/2-in. x 1-1/2-in. stock. The total length (9 in.) is from the long point of the 45-degree angles. Use a framing square to check that all the posts are at right angles from the work surface. Then check that the box itself is square by measuring the diagonal distance from the outside of one corner post to another-the two measurements should be the same.
Once everything is square, install the brackets with a 2-1/2-in. screw on each side through a predrilled hole.
Fasten the trim boards
Set your table saw to a 5-degree angle and rip the 1×4 down to 2-1/2 in. That will create a beveled edge to help shed water. Cut the side trim boards (J) and the back trim board (K) to length, but hold off cutting the front. Apply construction adhesive to the frame and set the trim board on two 1-in. spacers. Drive 2-1/2-in. screws through the frame and into the back side of the trim board. Angle the screws a bit to prevent them from poking through the face of the trim board.
Fasten the planks
Cut the back and side tongue-and-groove planks (L) to length. On the back, rip 1 in. off the first plank; that way you’ll end up cutting about 1 in. off the last one as well. I started the first one by removing the groove side. Apply adhesive, and fasten the planks with 1-in. brads, two at the very top of each plank and two near the bottom. Dry-fit the last two planks on the sides before applying adhesive.
Build the door frame and install the ball catches
Cut the door frame sides (F) and door frame top and bottom (G). Assemble the door frame with two 2-1/2-in. screws driven through predrilled holes in the sides into the top and bottom. Dry-fit the door frame in the opening; there should be about a 3/16-in. gap on each side and a 3/8-in. gap above the top.
Predrill a 1/8-in. hole through the sides of the frame 1 in. below the bottom of the top frame board. Using that hole as a guide, drill a 3/4-in. hole (confirm this size with the installation instructions). Either a Forstner or a spade bit will work, but drill in from both sides to avoid a nasty tear-out.
Slide the ball catch into the hole and hold it in place with the retaining plate. The plate can sit on the surface of the wood; no need to cut in a mortise.
Attach the strike plates
Set the door frame into place with the bottom of it resting on the bottom frame of the table. Mark the top and bottom locations of the strike plate using the ball catch retainer plate on the door frame as a guide. Bore out space with your 3/4-in. bit to make room for the recess in the strike plate.
Install the strike plates backward so the curved part of the plate faces in. If the plate protrudes toward the front, it will bump up against the door planks. Hold the strike plate in place, and mark the screw holes with a pencil.
Fasten the door planks and trim board
Adjust the ball catches so there’s an even gap on both sides. Cut the door planks (M) to length and rip 1-1/8 in. off the first panel. Apply adhesive to the frame and set down 1-in. spacers for the planks to rest on. Start the first plank 1/8 in. short of the corner post, and leave the last plank short 1/8 in. Fasten the planks with two 1-in. brads as low and as high as you can (into the door frame, not the table!). Fasten the trim board with adhesive and 1-in. brads through the back of the door panel.
Caulk and apply finish
Apply caulk (that matches the finish) on the sides and the back where the tongue-and-groove planks meet the corner posts. Apply caulk to the top side of the trim board on the door. Don’t caulk the tops of the other three trim boards. That way, if water does get behind the planks it can escape at the bottom.
A couple coats of an exterior-grade stain/sealer will add some color to your project and protect it from damaging UV rays.
Install the outer heat shield
Cut the 3-1/2-in. x 5-in. x 10-ft. galvanized steel dormer flashing (available at home centers) to length with tin snips. Install the flashing, keeping the top flush with the top of the box. Secure the pieces with 1-1/4-in. exterior-grade trim nails or small screws. Seal the corners with RTV high-temperature silicone (sometimes called ‘gasket maker’).
Caution: The bottom of the pan gets hotter without stones in it, so don’t ever run the burner without stones in the pan!
Install the inner heat shield
Cut the galvanized steel deck ledger flashing (sometimes called ‘drip edge’) to length with tin snips. Pound the bottom lip of the flashing flat with a hammer. Install each side so the bottom of the flashing is facing up, and the lip (that was bent flat) is even with the outside of the box frame but short of the planks. This will create a small air gap between the two pieces of flashing.
Build the tabletop form
Cut the melamine base (N) to size with a circular saw. Rip down the form walls on a table saw. Use a straightedge to mark the outline of the form. The inside dimensions of the perimeter walls (P and Q) should be 36 in. x 48 in. Let the perimeter walls run long; that way you’ll have a surface to whack with a hammer when it’s time to dismantle the form. The outside dimensions of the interior walls (R and S) are 12 in. x 24 in. Measure the actual burner ahead of time and check that it will fit before you cut and assemble the inner form walls.
Fasten the form walls with 2-1/2- in. screws placed about 10 in. apart. Melamine splits easily; be sure to predrill holes for the screws. The screw heads need to sit flush, so create a hole for them with a countersink bit. Because the walls can split even if you predrill the holes, drive in the screws slowly so you can stop before they split and create a noticeable bump in the side of the tabletop. Secure the corners with 2-in. brads.
Create a rounded edge with silicone
Run a healthy bead of silicone around the perimeter. Tool it into shape using a 3/4-in. dowel with the end cut at 45 degrees. While you’re tooling, let the excess spill over onto each side of the bead. After the silicone dries, those two lines can easily be pulled and scraped off. Black silicone works best because you can clearly see any excess that needs to be removed. Don’t use silicone on the inside edges. The silicone would make the form walls harder to remove, and those edges will be covered by the burner anyway.
Mix the concrete
Mix the concrete in a wheelbarrow or mixing tub, using a rake or garden hoe. I decided to darken my top by mixing in two bottles of Quikrete Liquid Cement Color dye. It’s important to get exactly the same amount of dye into every bag of mix. If you mix each bag individually, stir the dye into some water first, and separate it into three equal amounts, one for each bag.
Add in your color
I used Quikrete Countertop Mix. Some home centers stock it, but most can order it for you. Countertop mix works great because it can be poured a little wetter (like thick pancake batter) but still retain its strength. That helps prevent voids caused by air bubbles. Follow the directions for whatever product you use.
Fill the form
Set the form on a few 2x4s resting on sawhorses so you can beat the underside of it with a hammer to remove air bubbles. The form should sit fairly level. Spread out the concrete with a concrete trowel or taping knife. Pour in one of the mixed bags and beat the bottom and sides of the form to remove voids and air bubbles. Repeat the process with the second mixed bag before adding the wire mesh.
Set in the wire mesh
Wire mesh will strengthen the top. I cut down a 42-in. x 84-in. sheet (not roll) of remesh. The grid size worked out perfectly. Whatever size mesh you buy, keep it at least 2 in. away from the edges. I cut mine with a pair of small bolt cutters, but you could also use large wire cutters.
Once the mesh is laid in place, spread the last mixed bag of concrete over the top of it. Tap only the sides with a hammer to remove any voids; do not vibrate the rest of the form. This is very important: Vibrating the form will cause the remesh to sink. You’ll get shadow lines if the remesh comes within 1/2 in. of the table’s surface.
Screed off the excess concrete
Slide a 2×4 across the surface to scrape off the excess concrete. Wiggle it back and forth as you go, but try not to shake the whole form too much. That could also cause the remesh wire to sink and create shadow lines. Let the concrete harden a bit before you smooth it out with a trowel or taping knife. It doesn’t have to be perfectly smooth because nobody will ever see it.
Building a Table: Finish up
Take out the form screws, and remove the form walls with a hammer and a pry bar or sturdy scraper. Have a strong buddy (or two) help you flip the top upside down. Seal the tabletop with an exterior-grade concrete sealer.
Install the control panel (if your kit has one), and set your table base exactly where you want it before setting the top into place. Apply the leftover black and high-temp silicone to the top edge of the table. The top is heavy enough that it shouldn’t budge with normal use, but the silicone will create a stronger bond in case your burly, intoxicated brother-in-law falls down on it.
Insert the burner and make the gas line connections according to the manufacturer’s directions. Fill the burner with the recommended amount of rocks. Too few rocks and the pan will overheat; too many rocks and the flame will sit too high and be blown out by the wind.
All that’s left is to invite your friends and family (sans your brother-in-law) for a relaxing conversation around the fire.