reverse flow questions

[rjk welding]

I built a reverse flow smoker and it has a 60 to 80 degree difference from fire box end vs other end ..I made the rf opening a little over twice the size of the fb opening ...and ideas how to fix this ...

[Brisket Envy]

What are the dimensions of the smoker.
How thick is the steel?

[rjk welding]

Cc is 21"by 6ft fb is 22X22x19 the hole from fb to cc is 5 1/2" from bottom to top ...the rf plate hole is 6x20 and the stack is 6x19 all 1/4 inch material I know the fb side is supposed to be the hottest but that big of a difference? Just confused

[Clover Ridge Smokers]

Did you run your dimentions through the pic calculator before you started your build? I ran the numbers about and see a few problems. The RF plate opening is way too big and your stack is too tall. How big is the opening from the FB to the cook chamber?

[Big T]

Based off the numbers that you gave, your opening from the FB to CC(throat) is too large by about 40%-50% it should be 73.5 square inches and your RF gap should be the same as the throat or a little smaller. These two issues can create temp problems.

[rjk welding]

I did and doesn't mean I made a mistake I made the rf opening better hoping it would help and the fb opening is 5-1/2" from the bottom up ...so 5-1/2 by 19"...

[rjk welding]

18 1/4" and a height of 5 3/8". A guy on here pete came up with that... I appreciate all the help

[Clover Ridge Smokers]

Both your FB and RF plate (throat) opening are too big. I got the same numbers and Big T did. More than likely this is causing your temp difference problem.

[rjk welding]

Ok I'll try and close them up.....so to try this again do you guys know the formula to find the area of a half moon opening .....?

[Clover Ridge Smokers]

Here is how you calculate it.

http://www.mathopenref.com/semicircle.html

[rjk welding]

Trying to post picks now

[Clover Ridge Smokers]

This calculator works well too.

http://www.mathopenref.com/segmentareaht.html

[rjk welding]

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[rjk welding]

[rjk welding]

thank you..
With a raidus of 10.5 and a height of 5.5 I get 72 square inches. ....

[Clover Ridge Smokers]

That would be correct.

[rjk welding]

That's what my opening is at ..or am I just not understanding...ha I'd get bit by a snake if I was standing on it ...I measured up 5.5 from the bottom put a level across and cut ....right or no? ..I greatly appreciate the help

[rjk welding]

And big t ...you say the rf gap could be a little smaller ..as to help slow the air/heat down...?

[Big T]

I'm sorry rjk, I didn't realize that you had a half moon opening I thought it was a rectangle. Yes the RF gap is too large, I make mine the same as the throat but it can be a little smaller than the throat.

[rjk welding]

Sorry I should have specified that...and before I did have the rf opening 20x3.5 but still was off quite a bit ..would the stack being 3 inches to tall cause that big of a problem. ....I'm about at my wits end ...

[Pete Mazz]

Whew! I was worried I gave you the wrong dimensions.

Wait.... did I just say I could be wrong....

[Clover Ridge Smokers]

I would say having the stack too tall and the plate gap too large are causing the problem. the calculations from the pit calculator are very precise.

[rjk welding]

Lol I figured you were right pete....and ok thank you all for the help and taking the time ...I'll cut the stack down the 3 in and close up the rf gap again and do another burn ..thank you again

[Clover Ridge Smokers]

Let us know how it goes. One question we didn't ask you was what are you using for thermometers? If you are using a dial type mounted on the cooker, make sure you calibrate them. If you have one, I would suggest a digital like a Maverick. They tend to be more accurate.

[onesquin]

Tru tels are the only way to go. Somebody else just solved their problems by tossing their cheap thermometers and getting tru tels.