From an old home water heater I created a bbq, round shaped with 4 legs, total height 1 meter (40"), diameter 40 cm (16"). It's perfect for my home, beautiful and practical!
Step 1: Gathering Materials
For this instructable you will need of:
1)Old water heater, take it from some plumbers near your home or from your garage or from some garbage bin in the street !! .
2) Shears, screwdriver, hammer, sand paper and gloves to remove the outer insulation and the outer shell of thin metal from the tank
3) Grinder and a marking pen to cut the tank
4) Steel shelving column for legs
5) Drill for the legs and for the little air window with drill bits for wood and steel
6) High temperature black paint for legs and shell
7) Hinge with lock for the little air window
8) Rivet 4mm and 3mm and riveter for the air window
9) Bolts, Nuts and unscrew washers for the legs and 4 big washer for the supporting structure of wooden plate.
10) Round shaped double grill, I bought it on line of the same internal diameter of the shell
11) A scrap steel plate (bottom grill) to carry on the embers when burning in operation
12) Welding machine (optional) to weld the support of the bottom grill for the embers
13) Screwed bars and bolting for the wooden plate
14) Scrap wood for the wooden plate
15) One steel bar square shaped (Optional)
16) Wrenches for tight the bolts
17) Protective transparent coat (flatting) for the wood and a paintbrush to use it.
18) Clamp for tighten the threaded bars to insert the wood pieces
Step 2: Removing the Outer Layers
Take your old boiler and remove the outer shell with shears, than throw off all the foam insulation glued to the metallic surface of barrel. Use a hammer and a screwdriver to separate the insulation from the metal.
Once you can see the steel surface, use grinder and brush to clean and sand the surface. You can see how to remove the foam in this instructable:
"Make a Cheap Solar Batch Water Heater (Solar Preheater)" by chuck1011212 link:
Step 3: Cutting the Tank
You have to choose which part of tank to cut, I chose the side with the plate for holding it to the wall, see the red circle on the photos, because we will use it to hang on the wooden frame.
Take 13 cm ( 5") from the welding line of the bottom, draw a line all around and cut with Grinder the tank.
I cut also a square shaped groove to take in place the grill when cooking.
In the end you will find a shape like the one in the picture.
Step 4: Creating Legs
I decided to create the structure of the bbq with 4 legs took by an old and un used industrial steel shelving. Each shelving has several supporting columns, and these columns are suitable to be bolted somewhere, so I decided to join the columns and the shell of the bbq with bolts. I decided to have the top surface of the grill at 80 cm (31 inches) from ground when cooking, so I took two columns and I cut 2 legs from each column. The length of the legs is 75 cm (29 inches).
Step 5: Assembling the Legs and Grill Support
Now you have to drill the holes for bolting the legs.
I split the cylinder in 4 equal parts and I drilled the 4 upper holes 1 inch from the edge.
The bolts will protrude in the inner side of cylinder and they are perfect as grill supports.
Then I assembled the legs, put the grill in position above the bolts and adjusted perfectly horizontal the top surface of the grill with a bubble level and drew the position of the bottom holes.
Disassembled the legs and drilled the bottom holes.
Then I reassembled the legs with all the bolts in correct position and I noted that the structure was not so stable, so I decided to put 2 horizontal reinforcements bolted to the legs ( I took the reinforcements from the same column of the legs), to give more stability to the structure. Then I cut and smoothed the edges of the horizontal reinforcements, so you will not risk to be injured by the sharp edges.
In the end I disassembled the legs for the second time, sanded only the upper parts of them, the ones which are exposed to high temperature, and painted all the legs with temperature resistant black painting.
Step 6: Creating the Air Window
To burning the embers is necessary a lot of air, so I created a little air window at the same height of the embers, in the front part of the bbq. By this way you can open the window when the fire is low and close it when the fire is good. You can use it also for blowing fresh air in the fire, to give strength to it.
So, I took the marker and drew a square window, 1 inch height and 5 inch width (more or less) and then I cut with the grinder.
After that I put in the right place the hinge, the lock and the knob, drew with marker the right position of holes and drilled. I created the knob with an old bolt with big head and 4 nuts, as you can see in the photo.
In the end I used little bolts to put in place the window to test the correct functionality. I will rivet the hinge and the lock only after painting.
Step 7: Welding the Support ( Optional) for the Bottom Grill
To support the embers grill, thinking that the heat produced by the embers will deform the grill I decided to weld 2 steel rod on the bottom of cylinder, at the beginning of the elliptical head.
I welded the right rod in a position suitable to stop the movement of air door, by blocking it.
If you can not weld you can use also threaded bars, drilling the holes at the same height of the rods and installing them with nuts and big washers.
With the rod installed I could place the embers grill above them without problems.
Step 8: Drilling for Wooden Plate
A wooden plate to lay things when cooking is very useful so I decided to build a supporting structure with threaded bars to hang on the wood.
So I drilled 2 holes in the plate and respectively 2 holes in the cylinder and placed the threaded bars in position, ready to carry on the wood.
Step 9: Painting the Barrel
I sanded the rust and cleaned with paint solvent the steel surface, then put upside down the barrel and sprayed the same paint used for the legs, the most uniform I could. I Waited the day after, put right side the barrel and finalized the painting where it was no good.
Step 10: Reassembling the Structure
Once the paint was dried, I reassembled the structure. I Used the bubble level to mount the legs at the same height and to put the reinforcements horizontal. I used 1 unscrewing washer each nut and tightened all the bolts. In the end I measured the inclination of the grill, and it was ok!
Step 11: Riveting the Lock and the Hinge
This was the easier step, I took the rivets and the riveter and one by one I placed the rivet on the hinge and on the lock.
Step 12: Cutting, Drilling and Installing the Internal Steel Plate for the Embers
I found a scrap steel plate with many square holes and I though it was perfect as grill! It is more little than the cylinder, see the area in the red circle in the photo, and I thought this empty space is perfect to let the air pass through the embers while burning. I decided to fold the edge to create a wall so the embers will not fall down in the empty space.
After that I placed the plate over the cylinder, drew with the marker the circumference and grinded the plate to obtain a round shape. I Sanded the sharp edges and drilled the part without holes.
Step 13: Building the Wooden Plate
I used 2 nuts and 1 unscrew washer to lock one threaded bar to the cilinder and then 1 nut and 1 big washer to create some space between the wood and the steel, to reduce the heat of fire and so to prevent the wood from burning. In total I used 6 nuts, 2 unscrew washers and 2 big washers. Then I noted that, as you can see in the photos, I made an error when drilling the holes for the threaded bars, so the bars were not parallel! My idea was drilling the holes for insterting the bars inside the wooden pieces and than to lock all with 4 nuts and 4 unscrew washers, like a big sandwich. I solved this issues by drawing the two drilling line in the wood following the orientation of the bars and then drilled and inserted one by one the wooden pieces in the bars. It was not so easy as I needed to tigthen the bars with a clamp to put the bars in the holes. Then I closed the sandwich with 2 big washers, 2 little washers, 4 nuts and 4 unscrew washers. I used a wrench to force the nuts against the wood. The last step was to sand the wooden surface to obtain a perfect plain and to paint it with protective transparent coat (flatting) to give strength to the wooden surface.
Step 14: Cooking!!
In the end of all, I made a performance test burning the embers for 2 hours. No problems!!! Now the bbq is ready for cooking!!