I have used my GS40 with charcoal the first and only time I fired it up. I placed cold coals in the bottom of a 10.5 inch cast iron skillet. I put about the same amount of coals into a fire starter hand held pan to get the coals good and hot. I soaked my apple chips for 24 hours, not by plan, just ended up taking me that much longer to get everything ready for smoking. I only had kingsford charcoal right now so that is what I used. It seemed to burn faster than some of the other's I have seen reviews for.
When the coals in the coal bucket were good and hot (grey and red), I poured them on top of the cold charcoal in the cast iron skillet. I then, placed my soaked apple chips on top of the hot coals and placed the skillet inside the existing chip bin. It is a perfect fit.
Smoke started immediately and I lit the propane burner, which is directly under the original chip holder and put it on low. The temp stayed around 230 to 270. I ran it for 6 hours and the coals had just about burned out. When I got to the 4 hour mark, I had to start turning the propane up little by little to maintain the heat. I am ordering some of the coals that I saw on a forum on here to see if I can get longer life but I do not remember the name or where I saw them so I will have to look again.
Wanted to add that I have placed pictures of my first smoke as well as the finished assembly of my Masterbuilt GS40. If you look close at the photo of the entire smoker while cooking, you will see my cast iron skillet with the coals and chips in it below my water pan. It would be nice to see some pictures of a drip pan that can be used that does not block heat or smoke.
Edited by EdDisabledVet - 3/3/14 at 7:42pm