Originally Posted by pman777
It appears you have the same short thermometer I have. Is that the glow in the dark, $7 thermometer from Amazon? I also have a Walmart thermometer with a 12" stem. The good news is the short thermometer I have is accurate. The bad news is the reading on the wall is not worth much.
In my short time (seasoning run and then 2 cookings) I have learned there is a major difference between the center of the UDS reading and a reading near the wall. This discrepancy increases as the temperature increases. When my center reading is about 250, my wall reading is about 190. When my center reading is about 325, my wall reading is about 210. This discrepancy is a bit exaggerated with our wall thermometer because our's, I believe, is shorter than most other wall thermometers. Our's extends about 2" past the wall while many extend 4 to 5 inches in. My Walmart thermometer is 12" long.
Because of this I decided to try a heat dispersment plate. Right now I have a 10" aluminum pie pan just above my charcoal basket which is about 9" below my cooking grate. It reduces the discrepancy but only a small amount. Now when my center runs 250, my wall runs about 200 to 205. I need to increase the diameter of my 10" pie pan or raise it or some combination of both.
i was thinkin about the plate above charcoal basket too. if you used a 10" maybe ill run down to the old local pizza joint and ask if i can have an old 12" pizza pan and maybe a 16" too (im very much into tryin to scavange as many parts as possible so i can tell people i got less than $50 in it and produce great bbq) and try them mounted above my basket my next question is gonna be should i drill holes or not how big of holes and how many? or i'll just experament with them until i get a good balance. another thing is ill start mounting closest to the basket cuz i know aluminum doesnt hold heat so its more for the heat to go around ( and through if i drill holes). and yup i got the same $7 thermos on amazon .now i need to find the 12" thermo you got at walmart. was it lables a fryer thermometer candy thermometer or what? and how much? also after reading some more posts im gonna take my verticle pipe off and just run a valve off the nipple just to nip any drafting problems right in the bud. thanks for helpin me with my questions and being about the same experience with these uds' we can help each other with this