Originally Posted by ThatTrevorGuy
The reason I double foil sometimes is if I want 2-3 full blocks of coal on top of my bowl giving out a massive amount of heat for a long period of time yet at the same time having the double foil will help alleviate burning and help retain the heat much longer in my opinion.
What he said. Just a method of heat management. Also double foil is often used when you run out of HD foil.