Smoker Design

[bubbly top bbq]

I'm in the process of trying to design and build a smoker. I've done some reading and looking around. This forum and it's members have been a great help.
I was planning on building a horzontil offset with reverse flow that would use mainly wood. The cooking chamber I was going to use is 20" in diameter and 50" long.
I have three questions that I am looking for opinions on:

Is the length to diameter ratio for my cooking chamber okay?

Should I stay with a horizontil offset or look at a firebox along side and below the cooking chamber?

How big of a firebox would be needed for each style?

Thanks in advance for any and all opinions...

 

[msmith]

Btb what thickness is the metal your using. As far as design its pretty much what you perfer. That chamber should work fine, as far as fire box are you using round pipe or making a square box.

 

[bubbly top bbq]

The cooking chamber is 3/16". I like the idea of a square firebox for the added cooking area or for preheating wood. I've got some scrap 1/4" and 3/8" plate lying around if I went square.
I also have access to a pile of Sch 40 pipe up to 16". Would 16" be big enough for the fire box? I thought it should be at least 20" in dia. Probably could dig some bigger stuff up if round is the way to go....

 

[msmith]

I like the square box myself just because it has more room and helps with pre heating thw wood, the round ones work fine as well. If you do the square one id put a heavy gauge in the bottom. The 16" should be big enough to handle it though. My box is 30x30x2' but once i get the metal hot it dont take much wood to keep the temp up.

 

[bubbly top bbq]

msmith,

yah, I'm leaning towards the square and an offset. Makes it look like a train locomotive.
Do you think it worth lining the firebox with firebrick? I would think that might help hold the temp too. Thanks for the input too.....

 

[msmith]

Im sure the fire brick would help a lot. Im thinking about relining the inside of mine to help keep down on burning off the paint should have done that when I first built it. Theres a post showing a smoker with the tunning plates thats a reverse flow. I dont know how to move the link but look under Need help keeping even temp its under wood smokers. Name of the rig is cyclops

 

[ultramag]

Here is a link to the smoker Marvin references.

Cyclops Homebuilt Smoker

 

[msmith]

Thanks chad

 

[bubbly top bbq]

Thanks to you both for the input and link. Lots of good info it will help as I move along. Thanks again.....

 

[gunslinger]

Just to clear this up, that Cyclops smoker is not reverse flow.

 

[msmith]

Guess I should pay more attention when reading. I thought it was reverse flow. Must have seen that somewhere else. theres so much info here its hard to keep up sometimes.

 

[gunslinger]

We did have a bit of a side discussion about reverse flows on another thread. I personally don't think it's needed, but you know? To each his own.

 

[bubbly top bbq]

I saw a recent post that mentioned keeping the exhaust low on the cooking chamber. Even with the right stack height, does this location provide enough draw to keep smoke moving through the entire cooking chamber? Will tuning plates effect this at all? Not sure I understand why it's the best location. :oops:

 

[chris_harper]

robert, i cut in my smoke stack in the end, just below the food rack. i have planty of draw to keep smoke moving. i constantly have the thin blue coming form my stack. i don't know about the tuning plates affecting it, as i don't have them in my smoker. i think marvin can explain why it is the best location better than i can. he is the one that told me to put mine there. i had already put it in the top, from the rack up. i patched that hole, and put it in the end instead. works better. better heat control too.

 

[gunslinger]

I don't recommend tuning plates unless your building a pretty big smoker.

 

[msmith]

If you have a large smoker then the tunning plates work great. I didnt know about them a the time I built my smoker. So the reason I cut the stack under the grates is this causes a rolling effect. Keeps the smoke and heat more steady from top to bottom than just going out the top and out. Not saying that everone should do this but seems to work just fine on my set up.

 

[bubbly top bbq]

Thanks to all for your valued input. I've been grinding old welds off the cooking chamber and I am getting close to having to make some decisions about what I am doing. The more I think about it, the lower stack does make sense. I'll skip the plates, but leave room in case I change my mind. Who ever said I was indecisive? :lol:

 

[msmith]

When I started playing with the plates I found that I couldnt go the whole length of the barrel because of the stack cut in. I had to drop back and the plates are running only half way. Im still playing around with this but will eventually get it right where I wont it. When I was doing this the weather was pretty bad but had each end of the barrel within 10*. Its trial and error and you have to try diffrent things until you get the results your looking for,

 

[bubbly top bbq]

I quess trial and error is part of the learning process. Can't learn everything by reading. I guess I just have to start and see how it turns out and make modifications from there. My dad always said, 'If a jobs worth doing, it's worth doing twice...' :) Thanks again for the input.

 

[chris_harper]

yeah, i wish i had done a few things different with mine when i made it. now we have three drums at work i can get, but can't risk getting busted making another smoker right now. if only i had a welder at home, lol. i could cut the drums with the plasma cutter at work and do all the welding at home then. i might go ahead and cut them tomorrow, and bring them home, then do a little bit every weekend until it is all done, then weld it all up one sunday after i am off the clock. i already have a design in my head. two drums welded end to end, with a drum vertical on one end. the vertical would be the firebox. i would line it with firebrick.