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New build of a 125 gallon Offset RF Smoker.

post #1 of 19
Thread Starter 

I'm finally getting the time to build my new smoker. I've been wanting to do this for some time. This will be my first patio smoker and will then be on to my trailer mounted 250 gallon.


There she is. Had a interesting drive home with the valves off and the mercaptan smelling up the place. Lets just say people were staying a few car lengths behind me.


Began the calcs for he cut out etc. Yes, that's a protractor on an iphone.


Crude drawing of the dimensions.

Used CO2 to purge the tank of oxygen before the first cut. Had the bottle almost empty from my beer fridge. FYI, washed the tank out with a bottle of dawn soap and filled, emptied and them one more fill to rinse.

Marked cut lines for the torch. This will be the bottom.


Torched, removed all the old hinges and misc hardware. I'll weld a plate in there to accept the drain pipe.


Thanks for looking, more to post later.

Edited by robcalif - 4/22/14 at 11:07am
post #2 of 19

Hey Rob,

    Looks like a nice tank. Looking forward to following your build. What is Mercaptan?

post #3 of 19

Hi Jake,


Mercaptan is the compound in propane added to make it stink so it is obvious when you have a leak. I grew up in your neck of the woods, the home place is on the Isle of Palms from 1958 when only working class folks lived there year round. Those were the Tom Sawyer days! Dad is still there and will be 88 this month, nothing like a fresh flounder from the dock!



post #4 of 19

Hi Rob, If your planning on cutting the door out with a torch be forewarned the heat can make steel move in ways that can be difficult to manage.

post #5 of 19
Thread Starter 
Thanks for the heads up! Are you suggesting a cut off wheel?
post #6 of 19

Yes, and cut slowly meaning and not all the way through on the first pass. I made several passes before cutting through. Cut top and bottom of door through and the sides half way through then put hinges on before cutting the remainder of the sides. Had no warp what so ever to the tank or door. If your tank warped a little when you cut the valve area out sometimes you can relieve the stress by grinding along the edges of the cut removing a small amount of steel.

post #7 of 19
Thread Starter 
Great, that's what I was planning. I think I saw one of your earlier posts suggesting that to someone else. However, the valve area will be at the bottom, I'm flipping it upside down and using a fresh area. One, I didn't want the valve opening at the top and two the horizontal weld seam where I need to cut the door as well.
post #8 of 19
Hey Len,
Thanks for the explanation, I thought gas just stunk because of the natural sulfurs, I had no idea you had to add anything to it to make it that way. So when did you leave old Chuck town? I am actually a transplant from New York, the Navy brought me here and I couldn't leave. I like it a lot... except for the heat and humidity in the summer and fall months. It is the best place I have ever been, and in my line of work it takes me a lot of places, mostly coastal areas. I have only traveled through Bama a time or two though going to one job or another. I got a few really good friends from Bama that I met in the Navy,... Wild bunch of guys that I remember... Wild bunch of times too. The builds I have seen on this forum are really quite awesome, I got a feeling that Robs is going to be a good one too. I have learned a lot from reading the posts and Q-views from here too. My bride just got me a 18.5 WSM this week and I am going to smoke a turkey tomorrow to break it in come He!! or high water... probably have to do it in the garage cause the high water will be here. Might try to post a Q-view, getting tired of seeing NEWBIE under my mame. Keep Qu'in!!
post #9 of 19
Thread Starter 
Started moving some of my stuff to my old shop. Moved the trailer and a few tools over.

Got a few benches and my new welder all put together for a test run. Nice to have a new machine.

And a close up of the beauty.

By the way posting this from my iphone, bulletin board interface rocks. Good job guys.
post #10 of 19
Thread Starter 

Here's the link to my Feldons calc.


Any other suggestions?


[url=http://feldoncentral.com/bbqcalculator.html?cc=0,0,125,0,0,0,28875.00,9625.00&fb=24,24,20,0,0,11520.00,9625.00,119.7&ch=5,576.00,29.35&fi=0,0,10,34.56,0.44&fc=10.84,15.32,92.16]Link to BBQ Pit Calculator[/url]

post #11 of 19
Rob, afternoon..... are you building a 125 or 250..... When using Feldon's calc. , enter the numbers for the FB so it comes out 100% of recommended..... Then use all the numbers generated except FB/CC opening and area under the RF plate.... add 50% to those numbers.... Then make the FB bigger, as big as you want... the size of the FB has nothing to do with the other numbers.... make it convenient..... holds fire for a long time.... plenty of room for wood ash under the fire grate.... etc....
post #12 of 19

How thick is the steel on that tank?

post #13 of 19
Thread Starter 

3/16" steel. Weighs about 400 lbs.


I've been working on the firebox, these things take time to fab and weld up. I'm close to fitting the CC and FB together for the markup.

post #14 of 19
Thread Starter 
Alright, got some more done on the smoker. The FB to CC opening was cut.

Began fab on the firebox.

Marked and make three passes with the cutting wheel, cleaned and prepped the hing areas for welding.

Tack welded the hinges in place.

Finished welding the hinges and completed the cut in the doors, worked fantastic that way. Have a little bow, but will get that fixed.

Dry fit the CC to FB and marked the opening on the firebox.

Dry fit again.

More to comr
post #15 of 19
Rob, evening.... If you think you could use more room for heat and smoke to flow through the smoker, you can always cut out what I have marked in RED and still have the "DAM" in front of the FB...... Dave

...click on pic to enlarge.....

post #16 of 19
Thread Starter 
Good solid time on the smoker today. The firebox takes so much work. All the little details. I cut the door down and got it dry fitted.
And made the reinforcing frame.

I'll add more pieces to reinforce once a have the mechanisms in place for the vents. Sealed up the vents/old pipe stuff.

And cut the vents in the door.

Used the bullet hinges and have that welded on.
And now two shall become one. CC and the FB were welded today.
Welded the bottom by flipping it over, I don't like welding upside down.

Got the trailer frame built.

And dry fitted in place. Waiting for my axle and goodies this week.

And my sexy weld of the day from the FB to the CC.

Thanks fire watching!!
post #17 of 19
Looks great will be watching this thread. Want to start my tank build soon, so might have some questiions for you and others.
post #18 of 19
Before you go any farther........ look at the air vents in the door....... when you slide a damper, it needs the same space, or larger space between the cut outs to properly work.... example.... 2" wide cut out needs a 2 1/4" or larger space for the slide to open or close the 2" wide hole....

Unless you are building vertical sliding dampers... those may need a change......
post #19 of 19

If you are planning to add a sealing flange to the CC door, those bullet hinges are gonna give you trouble.

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