New Smoker Build Questions

[lumbrjk]

Hello everyone!

I recently acquired an old propane tank and plan on building an offset. I have done a bunch of reading but wanted to get your thoughts on the design. I have questions around the size of the stack (diameter and length), size of the firebox to cook chamber opening. I am not sure what would be optimal? Reverse flow or not? Any tips on racks? Where to put the water pan? Would you change anything? etc.

The tank is about 6 feet long (without the end cap), 24 inches in diameter, and made of 1/4 inch steel.

Thanks in advance for your feedback.

@Ahumadora​ - would love to hear any tips/tricks you might have!

[RonB]

We have several here who build smokers. Ahumadora and Henrik come to mind. It might take a few days for them to see this though.

And welcome to The Pit.
​

[lumbrjk]

Thanks! Excited to be here. Been thinking about joining for some time.

[Henrik]

Welcome to the pit! Material and size looks good. I would just use a single door for that size smoker. Too much fabrication with two doors, for almost no gain. The smoke stack should be 4-5" in dia, 60-70 cm long.

[lumbrjk]

Awesome, thanks for the input. One door and the size of the stack helps!

Curious how much space you would recommend for the opening between the fire box and cook chamber? Maybe offset the fire box about 6-8 inches from the bottom of the cook chamber?

Henrik

[Henrik]

4-5” will sufffice. If you plan on building a normal flow I would direct air up, then put the water pan above the hole to distribute air. Otherwise direct it horizontally and use a baffle to guide air to the other end.

[Spinaker]

Very cool! Looking forward to seeing this build. Henrik and Ahumadora make some amazing pits, I would poke them for some great info.

Welcome to the Pitmaster Club, looking forward to seeing this build develop.

[lumbrjk]

Progress from today. My base is only 20 inches wide. Maybe should have made it a few inches wider… will have to see as it comes together.

plasma cutter = amazing!

[Oakgrovebacon]

I have found that square tubing 5”x5” makes great stacks and much easier to cut holes for. (But I was using a grinder) 1 door is way easier that 2. I would also consider reverse flow to spread heat more evenly.

[lumbrjk]

I am really torn on whether to go with a reverse flow or conventional. Reading on pros and cons. I have to make up my mind soon! 🤪 I plan on mounting the offset tomorrow.

To make it reverse flow I just need to weld a baffle along the bottom and the smoke stack above the fire box?

[Oakgrovebacon]

Yes, with about a 4” gap at the end opposite the firebox. I would leave the bell end on the cook chamber tank and cut the baffle plate to follow the curve. You get more even temps than in traditional offset.

[lumbrjk]

Ended up working on the door tonight. Definitely needs a counterweight. Any hints on figuring out the right size/weight would be welcomed!

Cutting out the door and avoiding it springing on me was interesting. Cut the sides and welded on the stock and put some temp tacks on the body to hold it in place. Used a small jack to straighten out the middles of the horizontal cuts.

Had a grinder wheel dissolve on me. Ouch!

[WayneT]

This is really fascinating seeing you fabricate your new cooker. Thanks for posting the steps. It’s looking good so far. Can’t wait to see the final product.

[rlozinak]

This is looking good on seeing you fab the cooker.

[lumbrjk]

Attached the firebox, put the end cap on the cook chamber, cut out the opening to the cook chamber, and cut out the door for the firebox.

I was not able to get the firebox on perfectly, but hey, I think I am the only one that will know.

the firebox door is going to need some work to get it to swing freely because of the plasma cut. More on that tomorrow.

[lumbrjk]

jfmorris - great idea. I noticed that the weight of the firebox really offset the cook chamber and was considering it. I will add base and plan on putting on 4 casters.

[jfmorris]

lumbrjk if you look at the last picture in this post, you will see how Henrik put his legs on the bottom of the cook chamber on one end, but the bottom of the firebox on the other end.

https://pitmaster.amazingribs.com/forum/grills-and-smokers/home-built-smokers-and-refurbs/921871-two-new-smokers-being-built?p=925022#post925022

Basically, while the frame held things nicely for you while welding the firebox on, the firebox should have come first, then the support frame.

[lumbrjk]

Noted. Thanks!

[drobinson]

Don't forget the grease drain.

[lumbrjk]

Noted. I have the offset sloped ever so slightly so hopefully it will help flow. What size pipe is recommended? 3/4? Then add a ball valve?

[drobinson]

No special size, no pipe ---just a hole as you will place a bucket under it to catch the grease

[lumbrjk]

Adding a picture of the firebox door and cut of the inlet. Plan is to make a reverse flow with a removable (maybe) baffle to the bell on the other side. It will be about 4 inches off the bottom of the chamber.

I had already acquired a 5 inch smoke stack. With the relation of the door I think I am going to have to make a plenum above the firebox. Anything wrong with that? With this being a reverse flow, how tall should the stack be above the top of the cook chamber?

Henrik pointed out 60-70 cm for a conventional flow, would I do the same height minus the distance from the cook grate to top of plenum? Hope that makes sense….

thanks for all of the input!

[Henrik]

I would shorten the stack to 40-45 cm for a reverse flow. Not sure what a plenum is.

[HawkerXP]

Lookin good so far. Don't leave us hanging!

[lumbrjk]

Hey everyone!

Sorry for the delay, I was out of town.

got the smoke stack put in today. Went with the 40-45 cm recommendation.