# Modified SOB



## tobywan (Dec 19, 2009)

I have aquired a Tiernan, Son Of Brisket Cooker, 24X48 cook surface.  Had a buddy build a 24" diameter by 24" long firebox and thought I had got the damper and the opening between the firebox & smoker large enough but am having trouble getting it to draw properly.  Is there a specific ratio of damper opening to firebox/smoker/chimney.  I modeled it after brand name smokers(traeger etc) at a local shop.  Any help will be appreciated, Thanks


----------



## rickw (Dec 19, 2009)

Try this......


----------



## tobywan (Dec 19, 2009)

Great unit Ricky.  It is similer in size to mine and has what looks like all the extras I hope to have on mine someday.  Could you give me some stats?  Lenght & diameter of chimney, total sq inches of damper in firebox door, size of opening between firebox & smoke chamber.  I'd be interested in pics of the interior of the firebox & smoke chamber.

Tobywan


----------



## rickw (Dec 19, 2009)

The stack on my unit is 4" in diameter and a total of 30" long including the elbow. Did you try the link I provided in the first response?


----------



## tobywan (Dec 19, 2009)

Did just now.  Haven't been on enough forums to realize that was a link.  Thanks, This is what I should have done before I gave the welder to my buddy.  I'll let you know what changes I needed to make & how it works out.


----------



## rickw (Dec 19, 2009)

Good luck to ya, hope it works out for ya.


----------



## falconrod (Dec 19, 2009)

I can't get the files to open, don't have Excel.  Would you happen to know how high the stack should be for a standard CG-SFB.  Would the stack modification of extending the bottom of the stack to just above the grate cause the original stack to be ineffective???


----------



## solaryellow (Dec 19, 2009)

You can also use Open Office's Spreadsheet application to open it which costs you nothing but a few minutes of time. http://www.openoffice.org/


----------

