RF Smoker Planning (and the Build)

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I got the tank cut today. It is a little bigger than I thought. 30" diameter and 90" length It was in some bushes when I got the first measurements, so I missed the length and diameter by two inches. I will start again when I get home from work.
 
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Good to see you off and running.  Thats about the size tank I'll be looking for when I get ready to build again, something 24-30" in diameter and 8-10' long. 
 
Thanks bruno, but running may not be the correct description. It seems like just flopping around on the ground trying to learn how to crawl.
 
Since I was invited to the party and asked my input, here it is,...... good bad or ugly... ...if I was to take over this build at this point,

Here are the changes to your plans I would consider, I'll explain my reasons below.

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lets start with "c" first.   Due to the fact that you already cut the end off of the tank, I'd move forward with using it as a firebox, but I would not recess it into the cooking chamber as per your original drawing.

If it was still a full tank and I was building a square firebox, I would, but with the two round shapes, its going to be easier and look and function better just mounting them flush.  You will also gain more usable cooking area "c" by not recessing it into the chamber. And you wont be trying to but a reverse flow plate to a round tank either.

"A" is the most important, adding that second plate under the top of your firebox will keep the reverse flow plate from getting hot at that end and it will make such a difference in how even your temps are inside the cooking chamber.  Also , I think it acts like a insulator, and even though I have not tested this, I believe it  uses less wood.

I moved the stack, just becouse I think it would look better like this and will not be in the way if you need to add a counterweight to the door.Also will not take up any internal space.

I would cut a square out of the round end of the firebox and frame it in with angle so that you can attach a flat door. The flat door will allow you to put your intake vents in the door and allow the air to move in a straight line through the firebox into the cook chamber.  Even though some of my builds have the vents facing the front, I really dont like to do that.  Dont forget to add a second vent on the bottom of the firebox. You will thank me for that down the road on real windy and cold  days.
 
Thanks Ribwizzard

I had planned on building the firebox dor the way you described. I did not make it that way in the drawing for some reason though.

I have been thinking about an intake in the bottom, but not sure how to go about that. I will get it in place on the trailer and see what I think will work. I have a couple ideas, but not sure if I can make them work or not.

I like the stack on the end. I think I will go that route. I was concerned about having to either make the door smaller or setting the stack off center to not hit it with the door. I want all the cooking space I can get.

I am a little confused about moving the firebox and adding that plate. First off, I was planning on putting the RF plate about 1' above the top of the firebox. I was not going to have to fit it to anything round on the end, Just flat against the end of the cook chamber. I was thinking the top of the firebox that was inset in the cook chamber would act as the second plate you mentionedand help keep the temps more even. If needed I could add the plate to the portion that was not under the RF plate. If I don't set it in like that I will have to cut some off the end of the cook chamber to make it fit on the trailer across the back like I planned. I guess I could put it on one side though and keep it the length it is. Hopefully that is a little better explenation of the ideas floating around in the mud between my ears.
 
Hey , I messed up, I forgot that the firebox was round. The round top of your firbox should be the inner lid. Just take a piece of 1/4" plate and cap the top of it leaving a small air gap. Trim it in with plate to seal it off. Then on the inside of the cook chamber, install your reverse flow plate at the same height as the top plate you just added.
 
You know,

I have always said to put the firebox one 3rd under the cook chamber. Especially with propane tanks and the rounded ends.  But I would not do it with this build due to you cut the end off already.

What happens inside the typical reverse flow built out of a propane tank with the firebox tucked in 1/3 is that the top of the firebox becomes part of the reverse flow plate(. On my #19, I actaully used a solid plate welded to the top of the firebox and slid the whole thing into the cooking chamber as one complete unit. )  

The pro side is that more heat actually finds its way into the cooking chamber and you use less wood.

The con, more heat is generated on the firebox end of the cooking chamber,  To counter-act this , I install the secound plate under the top of the firebox. This keeps the end of the reverse flow plate from getting so hot.

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You will basicly be missing everything from the right dotted line , so dont worry about recessing the firebox, just mount it flush with the end.  You will burn a little more wood, but it will look better, be easier to build, and cook just as good.
 
Thanks Ribwizzard. I asked for your opinion and got it. I will be fitting the stack like you suggested. I will be putting an air intake in the bottom. I think I will stick with my plan on the firebox location though. I just read weedeater's build again. The firebox is attached very similar to my idea and his appeared pretty sucessful. If this don't work out I will take it apart and put it back together until it works like I want it to. I want the cook temps even everywhere in the cook chamber. I want a smoker with no more than 5* temp difference in any two places on the cooking surfaces. I may fail miserably, but that's what I want. Stay tuned and we will see.
 
I made some progress today. Started on smoker at 12:30, and worked until dark. I got the firebox door frame built.
Cut out the end of the FB and welded the frame in.
I had to weld some angle to the trailer frame to get the right placement of the tank. I also notched out the trailer frame for the door. It is upside down so I could make the intakes and slide that will be on the bottom.
Bottom intakes 2 4"x6" openings. I made the slide cover out of a piece of 3/16"x6" flat and used a couple pieces of 2" flat to make the braces that hopefully will hold the curve. I heated it and will let sit until tomorrow. Maybe that will work.
 
Looking good.  Know your glad to get it moving. Looks like it will have a lot in common with mine.  Cooked some more ribs this last weekend while working some on the trailer.  I am still really pleased with how it is working.  Left to right the temps are really close.  The top rack is a little hotter.  I think this is primarily due to the stack coming down to bottom grate level.  My theory is that it just traps heat up at the top and forces that heat down to the level of the upper grate.  Appears to be hotter all the way across the top grate not just at the firebox end.  I may cut some holes in the stack at the upper grate level but I am not going to be in any hurry.  I want to experiment and play some more with it before I try to tweak it any.  Joe
 
Yes, this will have a lot of similarities to your design. I copied your air intake idea, thanks. That's why I joined here, to steal ideas.:biggrin: I hope nobody minds. I will not be cutting the bottom of the cook chamber, or the top of the firebox out where they overlap. My RF plate will be about 1" above the top of the firebox also. This will basically create 2 baffles. We'll see how it works to even out the temps.
 
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Got a little more done this afternoon. Finished up bottom air intake slide, finished notching out trailer frame for door frame, and mounted firebox. I also cut the slits for my cook chamber to slide into. I am trying to keep up with the build hours. So far 10 total.
 
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I am trying to keep up with build cost. I might regret this later. I figured I would put it in here so I won't have to remember it or keep up with reciepts.

$40- fill bottles

$75- flux core wire

$400- steel (1/4" plate $150, 3/4-9 $45, 20" 4"x1/4", 20' 2"x1/8", 40' 2"x1/4", 5' 1"x1/4", 40' 1" 11ga tube, 6' 6"x3/16", 4' 6"sch40)

$20- grinder wheels

$535 - so far
 
Here is my plan for hinges. How do yall think this will look.
The one on the right is black on the bottom so it's hard to see. The top of the door will be 3" off center. The bolt for the hinges will be in the center so the top flange will not drag when opening. I ran out of oxygen, so can't cut any more for now.
 
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Lots of planning and you're making progress. You'll like it lower with the axle on top. I got my main cooking grate at about 36" for ease of access for shorter folks, my wife, and the pull outs make it a breeze. Keep up the good work.
 
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