Firebox Side Door - What Are People Using? Size?

[burnt goathead]

I'm new to this whole world of custom smokers. I've begun building my own traditional offset smoker, 20" diameter, 4' long cook chamber with a 2' firebox, out of 5/16" pipe. I would have preferred 1/4" but that's all I could find around these parts. I read Aaron Franklin's book and am in the middle of Greg Blonder's Meathead book. One thing I can't seem to find much information on is what people are doing for their firebox side doors and what size I should use for a 20" diameter pipe.  

I hear some people are using cast iron clean out doors for wood burning stoves or chimneys. Are they just welding those things onto the side? Can I just cut square with some 1/4" steel plate and use that?  I was thinking of cutting a 10"x10" hole for my firebox door as my opening.  

Any advice ya'll could toss my way would be much appreciated. Thanks.

 

[daveomak]

What ever you choose...  5/16" plate would be good, air inlets are important...  Try something like these...

Smoker exh and int 3 Ahumadora.jpg

• daveomak
• May 28, 2017

Smoker Exh and Intakes 2.jpg

• daveomak
• Apr 17, 2017

 

[kam59]

A lot of folks use their firebox as a grill especially back yard models. You could make it a top load and have your intake on the end.

Here is a pic of one I built that does this.

HPIM2436.jpg

• kam59
• Jun 23, 2017

HPIM2435.jpg

• kam59
• Jun 23, 2017

 

[burnt goathead]

Is there a place to purchase those little air inlet sliders? Are they called anything special?

 

[kam59]

You can buy the spinners through several supply stores. The horizontal slides are usually custom built to fit the firebox.

 

[joe black]

The top door is good for grilling or searing. The side door is good for cleaning out ash. As shown on Daves pictures, a small top door is good for extra air to push the heat and smoke into the CC.

As far as the size of the FB, it should have a volume of 1/3 of the CC. If you use the 20" pipe for the FB, it should be 18" long. If the FB was 18" in dia. It should be 21" long.