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JC in GB 250 Gallon Reverse flow offset smoker build

JC in GB

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Well, I finally got some shop time to start my 250 gallon smoker build. This is just the start and I will be continuing on throughout the summer as I only have a limited amount of shop time available.

I started out by doing a good deal of research on what was needed to build one of these units. I used the design template that daveomak daveomak provided and drew up the smoker plans.

So far, everything is following the calculations very closely. I am happy for that. As Dr. Who once stated so eloquently, "Only through mathematics shall we find truth."

I was able to get the old fittings cut out from the top of the gas cylinder and cut the doors. I was only able to get one set of hinges done though.

I have never used a plasma cutter before so this was a very sharp learning curve experience. The first old fitting I cut out with the plasma cutter was damn ugly. I got the hang of it by the third fitting.

Next part of the project will be putting hinges on the second door and cutting out the opening for the firebox. If I have time, I am also going to install the reverse flow plate rails. I need to calculate the arch length to achieve a 13 inch height from the bottom of the cylinder for the firebox. I will be getting that done today.

I was quite impressed at what a nice clean cut the plasma cutter made. A very handy tool.



Fittings cut off the top of the tank. Metal bar tacked welded onto tank for straight plasma cut on the door.

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Doors cut and hinges added to left door.

20210515_145729_HDR.jpg



Door and hinges work as planned. Very nice for such cheap hinges.

20210515_145715.jpg
 

sandyut

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oh yeah, gonna be watching this one through. Off to a good start.
 

JC in GB

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After looking over my design, I realized that the firebox is going to be a PITA to fabricate.

I liked the way jeffthewelder jeffthewelder did his firebox and I am gong to take a page from his design.

In my first iteration, I was planning on doing a freeform build of the box with clamps and welds.

I realized that this was going to be very hard to fabricate with the tools available and also be difficult to repair if needed.

I changed the design to make all parts of the firebox modular. Once the modules are fabricated then they will be assembled and welded together.

Right now, all I have is the hand drawn rendering of the new design. I will evaluate the design for fitness of function and then draw out a formal plan.

----- End of update ------

JC :emoji_cat:
 

JC in GB

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Firebox update:

I did a redesign of the firebox and sent the drawing off for a quote on the metal pieces.

The firebox will weigh nearly 700 pounds and the cost of the metal plates for it comes in at $1200.

That was $400 over my expected budget. That is not welcome news for sure.

JC :emoji_cat:
 

Berettaclayshooter

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What in the heck are you using for a fire box that is going to be 700LBS? Use 3/16" or 1/4' plate and if you want insulate with ceramic insulation jacketed with sheetmetal, not need for anything over 1/4".
 

LanceR

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Good morning, JC

1/4" steel weighs a bit over 10 pounds per square foot so 700 pounds indicates around 70 SF of steel. Can you share your design? And what are you concerned with being able to repair?

What plasma cutter are you using? And what welder?

Thanks,
 

JC in GB

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Good morning, JC

1/4" steel weighs a bit over 10 pounds per square foot so 700 pounds indicates around 70 SF of steel. Can you share your design? And what are you concerned with being able to repair?

What plasma cutter are you using? And what welder?

Thanks,
I am using a Miller 211 MIG welder and a Miller Spectrum 875 cutter.

Here is my firebox design. I made the end plates 5/16.
 

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LanceR

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Thanks. By the way, I'm embarrassed for you that you have a nasty Spectrum 875 cluttering up the shop. Feel free to box it up and ship it to me if you need more space and want to avoid the stigma. :emoji_wink:

I've had a Hypertherm Powermax45 XP on back-order for 5 weeks and they're saying to expect several more weeks before I get to the head of the line..... :emoji_disappointed: I have five tanks sitting around and have sheets of 1/4" steel for fireboxes and RF plates on the rack and don't want to snip them up with my Evolution 9" saw or a cutoff wheel. I'll be lurking around watching your build.

What are your tank dimension? Mine run from 120 to 75 gallons. Three are standard 120 gallon tanks and two are longer and smaller in diameter as they came off vehicles.

Lance
 

JC in GB

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I am making a 250 gallon cook chamber. Standard size 250 gal propane tank.

The cutter is not my, it belongs to the brother in law. He is great at metal work. I am just learning...

Follow this thread for updates....

JC :emoji_cat:
 
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