I used 2" (50mm) tube to build my DP including the door. The whole thing is that huge and heavy that a thick door was not an issue. The object of the thickness is to aid in the insulation of the smoker. Do NOT skimp on insulation and gaskets on a gravity feed.In the plans it has the doors being 1-3/4" square tube thus making the whole door that thick, is that because the gaskets are 1/4" thick? or can i just change them all willy nilly? (this also applies to the f/b door)
If anyone has some suggestions or precautions in dealing with a professional welder (15+ yrs) I would love to hear them. would it be offensive to ask if they have experience working with thin metal like this project or even suggest they utilize the stitch weld to avoid warping?
On your subject of pissing off your welder by asking them if they know how to weld thin metal via stitch-welding... possibly avoid that.
If the man has 15 odd years of doing it he must have some idea of what he is doing. You may ask him from an interest point of view, how he might approach welding the skin on etc, that way he can let you know if he has a handle on it.