This is a simple way to transform your horizonal barrel or kettle grill into a smoker maximizing cooking area & burn time between tending.
Two components, first the fuel is laid out in a fuse or maze pattern & lit on one end, bricks are often used to make the maze. Red construction bricks work but fire bricks take up less area & allow more fuel to be used.
Second part is a barrier between the fire & the cooking area several layers of HD foil will work but a baking pan makes it easier if doing this often.
DO NOT USE YOUR WIFE'S BAKING PAN!
:'( It doesn't clean after the cook!
For a kettle make a spiral fuse & I've seen a 22in pizza pan used.
Pics of a couple of cookers.
P.S. thanks To Old Dave's blog