# Gravity Feed Smoker build ?'s



## big eata 9

So I've been surfing the forum and generally I understand the concept of the gravity fed smoker.  Can somebody please explain how it's able to heat the entire smoke box Evenly?  What's/ Is there a ratio for size of firebox &  charcoal chute to size of cooking area?  All responses are appreciated!


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## r290

The fire box has sealed door panels.   This forces the fire/heat out into the cook chamber.   

As for size of fire box, really depends on how long between refills you want to go.

You can control the burn rate with a bbq guru.

The cook chamber must be insulated to help in keeping everything the same temperature.

In my build, I'm contemplating insulating between the fire box and the cook chamber to keep the one side from getting too warm


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## daveomak

Below is a tutorial on "how to build a great "Reverse Flow" smoker...  To heat the smoker evenly, the smoker needs to be air tight, except for the air inlets and exhaust...  any air leaks and it will not work properly....

http://www.smokingmeatforums.com/t/...others-ready-to-use-rev5-6-19-15#post_1264161


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## r290

Dave do those rules apply to a gravity feed system?   With the fire box full of say charcoal, the idea is to control the rate of burn by limiting air.   Or are you referring to the hole size from the fire box to the cook chamber


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## big eata 9

Thanks for the advice and formula.  So basically bc the smoker is air tight as the heat transfers over from the fire box to the cook chamber it disperses evenly? Why wouldn't there be a hot spot closer to where the heat/smoke first enter the cook chamber?


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## r290

Similarly to a reverse flow smoker, there is a transfer plate.   Mine uses C channel to help in an even transfer.   Notice the bottom plate.


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## big eata 9

Ok thx.


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## big eata 9

Do you use a water pan to help divert the heat also?


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## r290

That too is a good idea.  One can place a pan on top of the c channel closer to the opening.  Filling with bottle water, beer, Apple juice etc.

I'm not an expert as I don't do this for a living.  More of a monkey see monkey do.   But that is how we learn.  I would love to tag along with a film crew documenting bbq builders and cooks.   I love to learn.


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## unclebubbas bbq

http://www.smokingmeatforums.com/t/232875/gravity-fed-smoker-build-stumps-clone

Check out what this guy built, you will be amazed and it should answer your questions


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## daveomak

R290 said:


> Dave do those rules apply to a gravity feed system?   With the fire box full of say charcoal, the idea is to control the rate of burn by limiting air.   Or are you referring to the hole size from the fire box to the cook chamber




Do you mean "convection" smokers where the heat rises ??  Vertical style smokers don't have many rules....   Small air in and small exhaust out to conserve heat and smoke...




Big Eata 9 said:


> Thanks for the advice and formula.  So basically bc the smoker is air tight as the heat transfers over from the fire box to the cook chamber it disperses evenly? Why wouldn't there be a hot spot closer to where the heat/smoke first enter the cook chamber?



You want to create say, 100,000 BTU's in the FB and you want it to travel full length and back to the stack, EXCEPT for what is absorbed in the steel...  No waste of heat...    
By using an upper air inlet to move the heat out of the FB, there should not be a noticeable hot spot near the FB...  this is if everything is adjusted and built properly...   The FB should not get more than 50 deg. F higher than the CC if you built the smoker to move air correctly...

Before the "New and improved" tutorial, folks RF smokers were seeing temps 200-300 degrees hotter in the FB than the CC and CC's unable to reach 250 degrees...  The heat and smoke just couldn't travel through the smoker unimpeded...    The only thing that makes these smokers work well is reducing friction by allowing larger areas to move smoke and heat... 

If you do get a "warm" spot near the FB, and you are unable to adjust for it, you can install a heat shield at any time later....


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












Heat Shield.jpg



__ daveomak
__ Oct 7, 2015


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