New 80 Gallon Reverse Flow Build

Numbers look good.... I didn't run them... too early in the AM... Did you check the 50 times ????

Please read the entire link below... I think it will answer all of your questions...



Well, it took me awhile to figure out what the DODIS calculator is.... It is the calculator Alien and friends put together for building a Side Fire Box smoker.... measurements of "in use" smokers were tabulated and based on the smokers performance, a formula for construction was put together....
Smokers in operation by members on this forum had noticed some flaws in the operation of their Reverse Flow smokers using "Feldon's" or "Aliens" or "DODIS" as you call it, calculator and tutorial...

Below is the link to the calculator put together on this forum to overcome the shortcomings of the above mentioned calculators.....
http://www.smokingmeatforums.com/t/...others-ready-to-use-rev5-6-19-15#post_1264161


There are a few notations in the above link explaining changes to Alien's calculator..... below are some that I copied from that link....

Here's to "Alien BBQ" and the folks that first put the calculator together and "1728 Software Systems" for this great "Circle Calculator" and all the folks at "SmokingMeatForums", with a special shout out to Ribwizzard, that contributed their ideas and feedback while this thing was coming together..


Smoker Calculator reasoning
The concept for the changes is below.... Alien and his associates, did an amazing job putting the original calculator together... 100% of my numbers are based on his original numbers... small changes were made for the improvements due to design changes in smokers.....
The original measurements were taken from SFB smokers with tuning plates I do believe.... The advent of the RF smoker did not make any changes to the calculator... Now the exhaust has to travel twice as far as before, and the original FB/CC opening restricted the air flow from the FB, causing the FB to over heat... Some would get up to 450 deg and higher while the CC wouldn't get over 250.... And then there is the increased friction from the steel.... When using natural draft, any restriction/friction is very detrimental to the flow....
So, on a whim, the FB/CC opening was enlarged, the area under the RF plate was increased and the area at the end of the RF plate was increased... all by 50%.... That solved ALL the problems.... fuel consumption was reduced.... folks were happy....
I personally experienced members improvements and fuel usage by the letters/PMs they wrote me on their improvements...... One additional modification was suggested.... members here, tested a second air inlet to the FB.... directly across from the FB/CC opening... That was a significant improvement of some/most smokers.... If the FB was too hot, it could be cooled by opening the upper air inlet.... Also, the fire had a separate air inlet to adjust it's heat output.... It should be installed at or below the wood fire grate....
All of this has been tested and proven by members building smoker on this forum.... The only place you will find using these numbers... or it used to be... I'm sure many builders are now using these ideas for their builds.... this process has been going for at least 2 years....

Nice score on the tank.

Looking forward to your build.

Don,

A grinder with straight cut off wheel (.045") works great. But a fresh bimetal blade in a saw all works great too. Your choice. Some advice on compressor tanks, plan your cuts to eliminate rust problems with the bottom. I used an air tank on my build...still not done. It was a horizontal tank so the bottom was badly rusted. I flipped my tank to put the good metal at the bottom and the thinner stuff on top. You may want to use your "bottom" as the side for the FB cut out. Hope that makes sense. Looking forward to your build.

RG

Personally, I would not insulate the bottom or the door end where the inlets are... a lot of work for little gain... If I was to insulate the Cook Chamber, I would also skip the door and areas that were affected by the door opening and closing...

If you are thinking of insulating the exhaust stack, that would help with condensate.. A double pipe, open at the bottom will work....

.... click on pic to enlarge....

Dave is right about insulating, most bang for the added effort is on the firebox.  I got my wheels from Global Industrial, about $32 each.

I wanted something stiff and able to hold the weight but also be heat resistant, these are full roller bearing rated at 1000lbs each.  I am thinking

about changing those out though, they are pretty narrow and do not roll very well on the lawn or gravel drive.  I put some balloon tires on it temporarily

to move it around during the build.  I did end up making a small hitch for it, CAT 0 to fit my (wifes) lawn tractor as it was getting too heavy. I'll see,

my plans are to have it under a covered porch when not in use, move it out for cooks.  The hitch set up is for moving it from one side of the property

to the other, or put it on my trailer to cook elsewhere. 

The rust thing my tank, the bottom was not too bad but I did have some places where there were pinholes.  I just put those up top and filled it

with mig wire.  You really won't know until you open it up. 

One other recommendation (from Ribwizard) I did not do this and got lucky because my tank is pretty thick 3/16".  Is not cut your door opening first,

built your firebox, cut FB opening in tank and weld the FB to the tank before you cut the other openings.  Doing this will help control warpage on

your tank...especially if it is thin. 

I really do need to finish my smoker or at least update my build thread. 

Life has just put that project on hold for now.  Good Luck!

RG