80 gallon reverse flow build

[ghoster]

The lower air inlet..... may need to plug off the top half of the pie shape... Ski Freak did that to get air flow only to the fire... used the upper 1/2 for air flow, like the upper air inlet... BUT, as you probably noticed, his pie vent filled the entire door....

View attachment 359286

hmm, perhaps I should have lowered the bottom pie face to keep the airflow closer to the fire. will have a think about it.

 

[daveomak]

If you do lower it, place the open pies horizontally so all the air is at wood grate level or a bit below.... That way, that air supply will be used to control the heat output of the fire and then the upper air inlet can be used to control the air flow through the CC and move the heat out of the FB...

 

[ghoster]

If you do lower it, place the open pies horizontally so all the air is at wood grate level or a bit below.... That way, that air supply will be used to control the heat output of the fire and then the upper air inlet can be used to control the air flow through the CC and move the heat out of the FB...

Ironically that's what I had considered originally for that very reason, but all the pic's I'd seen had the pie openings running vertically, so thought I was over engineering it. Thanks Dave, I may have a crack at changing this now.

 

[kawboy]

I'll be watching this.

 

[daveomak]

ghoster, morning
Ironically that's what I had considered originally for that very reason, but all the pic's I'd seen had the pie openings running vertically, so thought I was over engineering it. Thanks Dave, I may have a crack at changing this now.

Ironically, some folks don't contemplate the function of stuff... Most smokers are built to "look good"... especially when it comes to stack height or diameter... Air inlets appear to be in that same category.. along with the size of the FB....
Smokers should be built to function properly... use less fuel... even cooking temps across the cooking grate... no air leaks... When all that comes together, they would have a smoker they enjoy using... "good enough" seems to be the deciding criteria, sorry to say...

There.. that's out of the way... AND, no one in particular was thought of while putting that rant together... just years of observation...

 

[motocrash]

ghoster, morning
Ironically that's what I had considered originally for that very reason, but all the pic's I'd seen had the pie openings running vertically, so thought I was over engineering it. Thanks Dave, I may have a crack at changing this now.

Ironically, some folks don't contemplate the function of stuff... Most smokers are built to "look good"... especially when it comes to stack height or diameter... Air inlets appear to be in that same category.. along with the size of the FB....
Smokers should be built to function properly... use less fuel... even cooking temps across the cooking grate... no air leaks... When all that comes together, they would have a smoker they enjoy using... "good enough" seems to be the deciding criteria, sorry to say...

There.. that's out of the way... AND, no one in particular was thought of while putting that rant together... just years of observation...

Well said Dave.

 

[ghoster]

I haven't had much time to work on the smoker the past few weeks. I don't like things to be half good so welded over the (nicely cut out) vents on the door, and managed to put a nice warp on it. will have a crack at straightening it. if not i have some 5mm sheet which i'll cut a new one out of. hopefully will get some time this weekend.

 

[gary s]

No reason in the world Not to have the Best of Both Worlds FUNCTIONAL and GOOD LOOKING
No one wants to put a lot of time and money into building a smoker that looks like crap.
My 2 cents worth

Gary

 

[ghoster]

Finally got some time to work on the smoker. Gave up trying to straighten the warped door. Stitched together some 1/4 inch offcuts I had and cut out a new door. Put some rectangular air vents down low, half above and half below the fire grate. Low vents give me 19sq inches, which is 30% more than I need down low. Still have the upper vent to control the air flow so have plenty to play with.

Also welded up the racks and tacked in the expanded mesh. Will weld on the fb face plate, make up some hinges and weld on the fb door. Need to straighten the cook chamber door, which bent inwards a little after it was cut. Only slightly so should be straight forward, I hope.

That leaves the smoke stack. I'm planning on welding together the pipe at 90 degrees and welding that into the side of the cook chamber. Wasn't planning on using a plenum. I'm going to make the smoke stack in two parts, so that the top part can be taken off when the smoker is covered up.

The end is in sight. Yeehah!

 

[daveomak]

lookin good.... should cook some great food..... Dave

 

[ghoster]

thanks for your help Dave

 

[ghoster]

Wife and kids away, so I gets to play! Did some work on the smoker this weekend. Welded on the FB door, cut out the chimney stack and welded it together. Made latches and fitted them on.

I'm pretty stoked given I had never picked up a welder before starting this project. All you guys out there putting it off, you have no excuse.

I decided to make the chimney detachable. Welded a 3mm steel band around the bottom of the top section. This allows the top section to slip onto the bottom section, which is welded to the CC. Chimney is 36" about the top of the CC. Looks tall. Don't mind the look.

Getting close to completing it now. Lots of grinding. A damper for the chimney, need to bend the CC door slightly, then fabricate and fit the CC handle. Will make up a counterweight or a door stop. Then its off the be sandblasted and painted.

Chimney removed and laid inside the smoker. Will be easier to cover.

 

[daveomak]

Fire it up before paint... You want to check for air/smoke flow and temp control.....
Some folks have made a plenum for the exhaust to get better air flow... Check with a test fire the exhaust
flows well using that "hard" 90 deg. elbow... Hate to see you change it after paint....
..

 

[ghoster]

You make a good point.

 

[ghoster]

Been a while since the last update. We took a 5 week holiday around Europe to escape the cold down here in Australia.

I fitted the temp gauges, and did a test run. Happy to report that the air flow is excellent.

Couldn't have been happier with the smoker. It came up to temp in about 40 minutes and held really well. I found I didn't need the top air vent on the firebox open at all, and the bottom air vent was only kept open about a quarter. (I did over spec the size of the bottom air vent as I did with fb/cc opening and downstream elements related to the airflow.)

Really good clean flow out of the chimney. The temp across the two sides of the cook chamber are pretty close to the same, so I'm glad I decided to go with a reverse flow. Did a low fuss cook a few weeks after the test run with some pork ribs which turned out great.

Now I know it flows fine, I can finish the fold up prep table, then its off to be sand blasted and painted. That takes me into summer down here, so looking forward to plenty of cooks.

Thanks for the input guys. This site has been so helpful.

 

[daveomak]

Whether or not you think you needed the upper air inlet on the FB, I suggest you use it and see what benefits it has to offer...

 

[gary s]

In reference to post #25 some people just don't get it
You are spending a lot of time and money building your smoker, You "CAN" make it look good
as well as "Functional" just do a little planning.
Upper air vents in the FB I would Recommend installing them, really work and help air flow.

Gary

 

[ghoster]

In reference to post #25 some people just don't get it
You are spending a lot of time and money building your smoker, You "CAN" make it look good
as well as "Functional" just do a little planning.
Upper air vents in the FB I would Recommend installing them, really work and help air flow.

Gary

Couldn't agree more. I've gone thru the pain of retrofitting the upper air intake to the FB, and lowering and increasing the size of the lower air intake.

Before and after pics of the FB door face...

 

[nanuk]

I was just thinking, if you had cut out your lower vent system square, you could have just rotated it 90 degrees and welded the square back in.... saving your time on the "Pie" system which I really like the looks of.

 

[ghoster]

did think about it but i had to lower the vents, and going with a rectangular vent gave me more volume at a lower height.