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Author Topic: Reverse flow offset build.  (Read 103 times)

Offline 220

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Reverse flow offset build.
« on: November 13, 2017, 02:00:29 am »
Made a start on another project yesterday a reverse flow offset smoker.
Started looking at it back in May but hadn't made a start, finally cut the tank I had so size is now set and I can start on the firebox. I was planning on a square firebox but after cutting the tank I realised the offcut from either end welded back together would be more than big enough. Seeing as I am doing this on the cheap using what ever I can scrounge from around the farm a round firebox it will be.

Offline Acebird

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Re: Reverse flow offset build.
« Reply #1 on: November 13, 2017, 09:50:28 am »
This is a smoker?  And what would make it reverse flow?
Brian Cardinal
Just do it

Offline 220

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Re: Reverse flow offset build.
« Reply #2 on: November 13, 2017, 03:35:42 pm »
Where a conventional offset smoker has the firebox one end and the chimney the opposite end a reverse flow has them both at the same end. They are separated by a full length baffle plate, smoke and air comes out of the firebox and are forced to flow under the baffle plate around the end and back through the cook chamber. The idea is to even out the temp in the cook chamber and eliminate hot spots.
Obviously the baffle plate ends up hotter closer to the firebox and radiates more heat into the cook chamber but this is at the point air temp is at its lowest so in theory temps balance out very nicely.

Offline 220

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Re: Reverse flow offset build.
« Reply #3 on: November 17, 2017, 04:09:26 am »
Day 1  cut the cook chamber to length & tacked the cook chamber offcuts together for the firebox
« Last Edit: November 17, 2017, 04:21:24 am by 220 »

Offline 220

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Re: Reverse flow offset build.
« Reply #4 on: November 17, 2017, 04:14:50 am »
Day 2 cut out the ends for the cook chamber
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Offline 220

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Re: Reverse flow offset build.
« Reply #5 on: November 17, 2017, 04:18:19 am »
Day 3 fully welded the two halves of the cook chamber together, tacked the door end in place and marked out. Tacked the legs to the cook chamber. Only took around 2 hours but when I sat it all together it started to look like an offset

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Offline 220

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Re: Reverse flow offset build.
« Reply #6 on: November 17, 2017, 04:19:31 am »
Day 4 Cut out air inlets, welded both ends of the firebox in place, fabricated and installed hinges and cut out firebox door. Spent about 8 hours on it and compared to the previous day I had worked on it the progress is much less obvious

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Offline Acebird

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Re: Reverse flow offset build.
« Reply #7 on: November 17, 2017, 10:35:55 am »
Holy cow or should I say pig.  Are you going to shove the whole animal in there at once?
Brian Cardinal
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Offline 220

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Re: Reverse flow offset build.
« Reply #8 on: November 17, 2017, 03:06:42 pm »
Not quite big enough for that, 48" x 22" I have a charcoal spit that I do whole lambs up to around 20kg.
20kg of lamb has been enough to feed the masses at any party we have and this should do a similar weight.

Offline sawdstmakr

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Re: Reverse flow offset build.
« Reply #9 on: November 17, 2017, 03:32:35 pm »
Wow, nice work.
What gauge steel are the barrels? Looks like it is a lot thicker than a 55 barrel drum.
It looks like you left the 2 circles together. How big is the pass through between the barrels.
Jim
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Offline 220

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Re: Reverse flow offset build.
« Reply #10 on: November 17, 2017, 03:46:43 pm »
It is actually the tank from a electric hot water system, only 3/16 but a lot thicker than the drums we have now days.
Cut the 1st full circle and then overlapped the second with the cut out for the pass through sitting over where the first circle had been cut. Saved a bit of material and cutting, 7" height on the FB/CC, have run all the numbers trough a few different pit calculators and it should be good.

Offline sawdstmakr

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Re: Reverse flow offset build.
« Reply #11 on: November 17, 2017, 03:53:59 pm »
Sounds/looks like it will work well and last a long time.
Jim
"If you don't read the newspaper you are uninformed.  If you do read the newspaper you are misinformed."--Mark Twain