how big should i build my firebox

[smoke_it_up]

i have recently started building a new smoker that has a 20"dia and was 47" long. I cut 16" off for a firebox and left 31" for the buisness end. should it be longer or is it big enough. it should hold heat pretty good its 3/8" thick.

 

[cbucher]

The only thing to keep in mind is the size of wood you will be using. If you are doing chunks and small stuff then you are okay.