Building a grill out of a 55-gallon drum is even easier than building a pig roaster, and is a great place to start your bbq building exploits! A 55-gallon drum is well suited to the task with a diameter of 22.5 inches and a length of 33.5 inches that equates to a cooking area of 22.5 inches by 33.5 inches!! For any occasion where you need to cook a lot of meat simultaneously this type of grill is ideal!
Grill plans or any form of fire pit or barbecue pit plans, similar to pig roasters, seem to be pretty hard to come across on the internet, so I've gone ahead and put a simple little design review together for you. The starting point is obviously the 55-gallon steel drum. These are pretty easy to come across, with used 55 gallon drums going begging all over the place once you open your eyes, but try and source one that has been used to store food stuff as opposed to any toxic chemicals. If you're having trouble sourcing a drum for your barbecue, and the only one you can lay your hands on has a questionable background, don't worry. Before you ever try to cook food on your new grill you will light a couple of really hot fires in it to burn off any contaminants.ADVERTISEMENT
So when you've sourced your drum, the first thing to do is cut it in half, as described for the pig roaster. Now the main difference between building a pig roaster and a grill, is that the grill doesn't really need a lid. With a pig roaster the cooking can span many hours, so there's a much greater chance of getting rained on, depending on where you live, so the ability to be able to protect your pig roast quickly is essential! With the grill however the cooking tends to take a lot less time, so there's less chance you'll get caught out in a rain shower, so I typically don't bother with lid or cover. Instead of a cover for your grill you can use the second half of the drum for another bbq grill. If you don't use it, you will no doubt have a guest that sees your grill and will want to attempt their own! So you can be the good Samaritan and donate your unused half!
Once you have split the drum or barrel in two, you need to place a fuel grate in the bottom of the drum to hold your charcoal. I find that extruded metal sheet is best for this, it's readily available from hardware stores. Cut a piece roughly 16 inches by 30 inches to sit down into the drum. This will raise the charcoal off the bottom of the drum allowing air to circulate in under and feed the fire. For this air to get in under the charcoal, you need to drill some ventilation holes into the bottom of the drum, a good spread of half inch drill holes along the bottom of the drum usually does the trick. The next addition is the food grate, this is positioned over the charcoal grate. The simplest way to do this is to get some steel mesh and cut it approximately to size. Place it over the top of the barrel so that it sits flat on the barrel, and bend the oversize edges down over the sides of the barrel leaving you with an open top drum grill, and you're done!
Although you can use steel mesh for a quick solution, if you plan on using your grill over and over it's best to go to the trouble of making your own food grate out of quarter inch steel bar. You can weld up a quick outline frame to match the open side dimensions of the barrel and then tack weld on lengths of the quarter inch steel tube to form the removable grate. The reason you're going to all this extra trouble is that this grate will be infinitely easier to clean once the bbq is finished! A little extra effort at this stage will make for a much easier life in the long run!!
That's the basics of the oil drum grill. Now you can use your own judgement and preferences to add a support frame and worktop space around the grill to your own specification. I usually use 2-inch angle iron to construct my frames. Check the homepage where I elaborate a little more on the whole process. I've also included some sketches to help you visualise what I'm talking about. I hope you found this helpful, remember the best way to work out the kinks in any design is to start building. Don't worry about every detail of the design before you get the angle grinder out, just get building and see what works, all the materials needed are cheap and plentiful so have a go!