Here is the current pit I am building. Going to be a long post... offset 125-gallon backyard model.

[realdocBBQ]

Well, I've built a few, and am working on trying 'break into' a slightly higher end market. So this cooker I am hoping is going to come out nice and snazzy and bring a good price at the end of it all from some yuppie suburban dude wanting a nicer backyard offset to complement his higher-end Traeger or something. lol

I've had this tank about 9 or 10 months. Finally decided to get to work on it, but this spring in OK has been exceedingly rainy, which limits the time and ability to work on it. I use my friend's shop and tractor, and don't want to leave ruts in his yard, so I have to lay off for days on end when we get a lot of rain.

Here's the tank:

As you can see - lots of valves and such that needed to be cut out. Some people leave these, but I like the cleaner look of cutting out and patching the tank.

Tank is right at 1/4" (.250wt) thick.

So patching the tank is a bit of a challenge. I want to make the patch contour to the tank, so the best way I've come up with is using my band roller to roll a long(ish) piece of plate to the same contour, then cutting it into pieces and welding them alongside each other to form a patch, then trimming, grinding and beveling the patch, tacking it into place and then fully welding it in and grinding my welds (which are undeniably ugly and amateurish) flat to try to make the eventual patch as unobtrusive as possible.

And a profile view to show the appropriate contour/curvature.

I don't know how many pics are allowed per post on this forum, so I'll start a followup post to record more progress.

This may not be the best, most appropriate or most efficient way to patch a tank like this, but this is what I came up with, and I'm fairly pleased with the end result.

 

[SmokingUPnorth]

Gonna be a cool build…Following!

 

[realdocBBQ]

Next is starting in on the firebox. This is going to be an insulated firebox - 24" pipe inside (.250wt), 28x28x28 outside. Because this is a backyard pit, I want to save some weight, so I did overcomplicate things a little bit. I decided to do 1/8" (.125") thickness for the outer plate, but I didn't want the internal pipe (the actual fire chamber) to have those thin ends. So I used my new Primeweld CUT60 plasma and the circle cutter jig to cut out the endplates. Because the endcap is thicker than the wall of the external box, I needed to inset the 1/4" cap by 1/8" or so to try to match up the ends. Various ways I could have done this, but as I said, I sometimes overcomplicate things. lol So the endcap was cut slightly smaller than the diameter of the pipe - so it could 'nest' inside the pipe.

The other endcap is larger, and will overlap the entire end of the pipe, including the pipe wall - there is a method behind this madness, as you will see later...

This is the endcap with the throat opening cut into it with my Metabo, then beveled on the edges, again for better welding joinery.

Time to rotate the plate around to fit into the pipe properly.
Something a lot of people don't realize - this pipe usually isn't truly round. It's 'egged out' some, meaning just sitting there under its own weight, it will sag a bit and widen on the sides and shorten top to bottom. This happens at any of the larger sizes, I think 18" or greater, if it's 1/4" wall thickness or so. I believe (not 100%, but I THINK) that I was told this happens all the way up to 3/8" wall thickness, where it is strong enough to hold its own weight. This is why they love 3/8" so much for oilfield pipe, where it sits around for years sometimes. So, anyways, this presents an issue when you are cutting out a perfect circle (or as perfect as my palsied hands can achieves, lol) and then trying to fit that circular cutout into the slightly oval-ish pipe. Problems.

Anyways, rolled it around, got it fitted into the right (ish) spot and tacked it in place.

Here is a closer look at the 'inset':

Then fully welded into place:

Ground down my ugly welds so the 1/8" endplate will sit on the edge of the pipe, hopefully just about level with the surface of the 1/4" endcap.

Then began welding around in a radial pattern, like tightening lugs on a wheel.

Unfortunately, due to the endplate being so thin, I did get some warping of the material from the heat input, so I will have to deal with those as I move further in the build.

Had to find TDC (top dead center) on the pipe with the throat opening in a level position, so that I could mark a reference point to be able to properly 'clock' the two endplates to each other in relation to the throat opening.

TDC marked:

Then marking the center of the plates, lining them up and shifting around to get them properly fitted on the end of the firebox pipe.

And the endplate on the throat opening side fully welded in place.

The other endplate also in place (this is the endplate for the firebox door). Also radially moving around to try to minimize heat input, lots of shifting it, laying on its side, rotating, rolling, etc. Finally got it done.

In general, it is coming together.

Now, insulation. 2 layers of 1" thick 2400ºF ceramic fiber mat from Amazon.

Next post - putting on the sides....

 

[realdocBBQ]

My fitup and joinery is certainly not perfect, even though I tried to take as much time and measure as carefully as possible when cutting out my plates, trimming, cleaning up the edges, etc.

I had to use pipe clamps at times to pull the edges into place well enough to get them tacked in.

Eventually got all the sides in place, but haven't completely welded up all the seams yet. Probably about 80% done, but they are all in place and welded out enough to hold there so I could call it a day (this was on Wednesday, two days ago).

Today is Friday, and I worked until noon, now about to change clothes and go back out to the shop to finish welding this, and start on the door...

The door is going to be a double layer 'bank vault' style door, with insulation inside. Similar to this one I did on my first smoker, which resides in my backyard.

This is the reason for the larger plate that will fit/overlap the pipe, so it will seal with the door closed. It will be 1/4" plate inside, then insulation, then 1/8" plate outside. I will also be putting in a butterfly damper through the door, so I will have to line up the two door plates perfectly before welding them all up. Should be a little bit of work, a little tricky, but I think I should be up to it. I hope. lol

On the one in my backyard, I just use the door itself as the air inlet, but - as I mentioned before - often people are looking for a 'feature' that is neat and looks cool, even though it may offer no real functional benefit. So I'll put a butterfly damper in, so people can keep the door closed while still allowing them to adjust airflow.

We'll see how it turns out in the long run.

 

[realdocBBQ]

Oh yeah, forgot about the wheelios - this is a big part of the higher end cooker market. Expensive, but that will get added into the final price. Details make the difference in a higher end build, I think. Or I hope, anyways. lol

 

[jaxgatorz]

Off to a nice start. I will grab my seat and settle in...

 

[ajbert]

Looking good so far!

 

[bluesrv]

Looking gorgeous!

The wheels are certainly going to be nice! Are you adding breaks to them in case owner wants to keep it in place?