Reverse flow build

[cysmoker]

Finally decided it's time to build my stick burner. Currently I smoke on a Green Mountain, Rec Tec, or my PK but I want something I can play with a little more.

I picked up a 60 gallon air tank (20inx44in) and a 15 gallon air tank. I did all of my calculations based on DaveOmaks thread, and came up with the following:

FB/CC opening = 55.44 in
Area under RF plate = 55.44
Area at end of plate = 55.44
Air intake area = 13.86" (will do around 3" for the upper and 11" for the lower)
Exhaust stack volume = 305 cubic in
Exhaust Stack = 4" diameter by 24" height
RFplate width = 17"
Height of FB/CC opening= 4.75"

Do these numbers look accurate? The only other question I have is on my fire box. My 15 gallon tank is a little smaller than suggested. A 20 gallon would have been better but I couldn't find one for a reasonable cost. Will the 15 gallon tank be a problem or should I fab one up out of steel? Looking forward to getting this thing up and smoking!

 

[daveomak]

15 gallon FB will work... The metal thickness of an air tank is pretty thin... Just beware of that...
All of your work could only last 4-5 years, depending on usage...
For the exhaust stack, it should be lengthened to ~ 34", so it has enough "SUCK" to promote good air flow through the smoker.. The 4" diameter should work OK...

 

[cysmoker]

15 gallon FB will work... The metal thickness of an air tank is pretty thin... Just beware of that...
All of your work could only last 4-5 years, depending on usage...
For the exhaust stack, it should be lengthened to ~ 34", so it has enough "SUCK" to promote good air flow through the smoker.. The 4" diameter should work OK...

Thank you sir. These tanks are thicker than I thought they would be from the looks of it. I haven't cut into them to put a gauge on the wall thickness but the guy I bought them off of had planned to also build a smoker and had started making a cut for the door so I could see the thickness a little. I didn't like his positioning so i welded the cut back shut (about 8" long is all it was). I'll most likely be bored of it and want something different in 5 years anyways lol.

 

[cysmoker]

Here's a few pics of the start of the build.

 

[cysmoker]

Making good progress on the smoker. About to the point of putting in my stack/exhaust. Can I use a 4x4 square tube instead of round stock? I think it will be easier to attach than round because I don't have a 4" hole saw.

 

[daveomak]

4" square allows for about the same air flow as 4" round... It should work fine...
4" round = 12.6 sq. in.
4" square = 16 sq. in..
The surface area of the square tube is greater than the surface area of the round tube and creates more friction.. That's why they are about equal in air flow... and the corners don't flow air well..

 

[daveomak]

That air tank looks to be close to 1/4" material thickness.. the tag should tell...
I have one of those hooked to my air compressor for additional air reserve...
It will make a great smoker....

 

[cysmoker]

That air tank looks to be close to 1/4" material thickness.. the tag should tell...
I have one of those hooked to my air compressor for additional air reserve...
It will make a great smoker....

Thanks for the response! It is 3/16", so a lot thicker than most air tanks out there I think. I know it's been chewing up my cuttings discs when I cut the door out. I'll try and get some pictures of the progress up here soon.

 

[daveomak]

You've got a dandy CC there....

 

[smokin peachey]

I wonder how this smoker must look by now.
Hopefully we will see some more pics soon.

 

[cysmoker]

Well, life happens and this project got delayed a bit as I had too much other stuff going on. Finally got around to working on it again and ran into an issue with my door/hinges/banding around the door. I made the top cut of the door, then welded my "band" on (which I'm an idiot and welded it completely instead of tacking first), then welded on my hinges. Then I cut in the sides, welded on the bands, then made the final cut across the bottom. Great. My problem is that I didn't think about the clearance for the top band across the body of the tank for when the door swings open. I forced it open and got it to go. I tried putting a bevel on the lip of the body. Didn't help. I then took a pair of vice grips and tried to bend the lip. Can't get enough on it. So the door will not close now.

If I cut the hinges back off and move them so they attach to the top band instead of the door it's self will that give me enough clearance? What other options do I have? I can cut the top band back off but I'd rather not. It's a 2" wide band x 3/16" thick. 1" of the band sits on the door, and the other 1" I designed to sit on the body as a seal.

Here's some pictures of what I'm talking about. Any input and criticism is accepted and welcome. This is my first big metal working project so I'm still learning.

 

[daveomak]

I'm not sure if I know what I'm looking at for sure.....
Is the door on the left ??? Is it hung up in the air due to poor fit up ????
Is the strip down the middle of the picture, a door seal strip ??? Is it welded to the door or the CC body ???
Here's a tip..... NEVER fully weld ANYTHING on your smoker... Skip welding works fine and helps to stop stuff from moving... Even the RF plate... skip weld it... Even the FB... skip weld it...

 

[cysmoker]

I'm not sure if I know what I'm looking at for sure.....
Is the door on the left ??? Is it hung up in the air due to poor fit up ????
Is the strip down the middle of the picture, a door seal strip ??? Is it welded to the door or the CC body ???
Here's a tip..... NEVER fully weld ANYTHING on your smoker... Skip welding works fine and helps to stop stuff from moving... Even the RF plate... skip weld it... Even the FB... skip weld it...

The door is on the right and the seal strip is welded to the door. It is hung up in the air and won't fully close. I'm trying to figure out what to do, short of taking the seal strip off to get it to close like it should.

The seal strip is hanging up on the CC body.

 

[cysmoker]

Maybe this will help show it a little better. This is the door fully open. You can see the seal strip on the door, the door goes flips down clockwise. Basically the leading edge of the seal strip pretty much meets the edge of the cut on the top of the CC and stops there.

I'm wondering if I cut the hinges back off, rotate them to the left on the CC body, then weld the other side to the seal strip of the door if it will change the lift angle enough to give me a enough clearance. So basically moving the lift point on the door by about 3".

 

[daveomak]

You welded the hinge in the wrong place.....
Looking at the picture in question, the center pivot of the hinge, MUST be to the left of the seal strip.... About 1/4".... That allows for materials to not be in the way when opening and closing of the door....

 

[daveomak]

With a grinder, cut the hinges lose from the smoker....
Set the door in place.... centered in the hole.....
Tack the hinges in place and check the door travel....

 

[cysmoker]

With a grinder, cut the hinges lose from the smoker....
Set the door in place.... centered in the hole.....
Tack the hinges in place and check the door travel....

You welded the hinge in the wrong place.....
Looking at the picture in question, the center pivot of the hinge, MUST be to the left of the seal strip.... About 1/4".... That allows for materials to not be in the way when opening and closing of the door....


View attachment 423586

Now it makes sense. That will be on tonight's to-do list. Thank you sir!

 

[daveomak]

MAKE SURE the hinge pins are in a line...

 

[radioguy]

Hinges shouldn't be centered on door cut. Offset them to the outside, this will make the hinge point lift the door and give clearance for the seal.

RG

 

[cysmoker]

Thanks for all the help guys. I got it redone last night and now opens like it should. Starting to look like a smoker.