I am building a smoker with offset fire box. Its 2 250 gallon drums cooking chamber and half 250 drum for firebox with 6 in pipe into cookimg chamber. My doors i cant seal that good ive tried the flat rope for like wood stoves. But dosnt work that well. Still alot coming out more than i think. My exhust pipe is 2 1/2 but i dont have it going up yet. Would not having up pipe affect my temp. Mater how much wood or charcoal. Could not get temp to hold or go above 175. Any help would be appraicated. Using rtv with plastic wrap to make seal was next idea to try to make form of door then remove plastic leave mold for seal.