# Flow problems with my custom build smoker



## metaldoctor21

I built this smoker and it seems like I am trapping all my heat at the firebox.  My cooking chamber is 36" long and 16" diameter 1/4" wall pipe.  

My fire box is 18"x18"x18" 1/4" thick steel.  

My exhaust is 4" pipe 24" long.  It comes out the end similar to a jambo pit.  It has a 5.5"x5.5" square cut in it and a pocket welded to the side that the pipe bolts to.  The bottom of that hole is 6.5" from the bottom and the top of the hole is at 12" from the bottom of the cooking chamber and it's center in the pit.  My cooking grate is 1.5" up from the bottom of the hole.

The intake vent is a 5" circle.  The center of the hole is 6.5" from the bottom of the fire box and in the center of my charcoal grate.  That leave 4" under the charcoal grate to the bottom of the fire box.  The hole is center on the end in the door.
The fire box to cooking chamber hole is 5"x10".  The bottom of the hole is 6" from the charcoal grate and the top of the hole is 1" below my cooking grate.

If anyone has any suggestions or sees anything wrong with my design I would appreciate the help.  I am new to smoking and to this forum.  I will try to get pictures posted.  Thank you.


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## metaldoctor21

Fire Box Side












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## metaldoctor21

Front Side












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## metaldoctor21

Exhaust Side












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## bkleinsmid

Whats up Doc?.........sorry, I had to do it.....

That is a great looking build. My 1st thought would be that the exhaust is too small in diameter. Have you run the calculations on the sizes yet?

Brad


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## metaldoctor21

I did run the calculations and everything is what it's supposed to be.  Another thing I noticed is that when I put charcoal in the cooking chamber to use it for direct heat the coals will go out.  I have the charcoal on a tray about 1.5" from the bottom so air can flow under them, but they won't stay lit.  That is another reason why I am assuming it is a flow problem.


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## sqwib

That is a beauty.

Hey can you do me  favor and temporarily raise your grate above the intake and try again, I would love to see if that helps.

Everything else looks good, I would prefer the stack outlet at the top of the tank but thats just me.

Hey Ribwizzard, think you can help us out here?


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## sqwib

I'm curious to see if a flow beneath the fire would improve the draft, If I was a betting man I would say moving the grate above the inlet and allow air to come in underneath the heat source will help with the drafting.


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## daveomak

Doc, morning...... VERY NICE smoker........  I like it.....  Where did you get those dimensions from....  did you take them from another Jambo smoker ??     Using the Feldon's calc, your FB is 241% of recommended which should not pose a problem...  FB air inlet is large...   I would plug the top half and try it...     Also, the configuration of the smoker, I don't see any way charcoal will stay lit under the food grate....   Does Jambo say their smokers will work with charcoal under the food grate ??  And I can't remember for sure but, I think Jambo FB/CC opening is above the food grate.... and the exhaust is below the food grate.....  I could be mixing that up with another smoker...   getting too old to remember it all....

In the link, is what I came up with for a SFB smoker, which is similar in design to yours....  

Link to BBQ Pit Calculator

We will work with you to get this thing working.....   Dave













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## metaldoctor21

I have tried moving it up 1.5" from where it was at in the photo and that didn't seem to change anything.  I will try to move it all the way above the inlet this weekend and see if that changes anything.


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## metaldoctor21

You are correct on the jambo configuration.  I was just trying to give an idea on how my exhaust was because I didn't have any pictures posted at that time.  I just came up with the dimensions for the pit as I was building it.  I had a family friend who was my smoker expert helping me, but he past away due to cancer before I was able to finish my pit in the spring.  I built my fire box bigger, so I could store more charcoal in their for a longer burn time.  Do you think the size of the fire box is effecting anything?  Also what do you mean by their is no way charcoal will stay lit in the fire box with my configuration?


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## sqwib

metaldoctor21 said:


> I have tried moving it up 1.5" from where it was at in the photo and that didn't seem to change anything. I will try to move it all the way above the inlet this weekend and see if that changes anything.


One more question, did you ever see any smoke come out of the inlet hole?


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## metaldoctor21

I have some more photos I will try and post this evening.  I am trying to post them from my phone and am having a problem getting them to load.  Will moving the stack up or up and a couple inches from the end have an effect on anything?


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## metaldoctor21

Yes smoke does come out the inlet hole.  Also when I open the firebox door smoke will flow right out of the fire box.


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## daveomak

There are many designs for smokers......   What style was your original thought....  It seems to be a mix of different designed smokers....  

I notice you have no tuning plates, which would be appropriate for that smoker...   Then the stack "plenum" would be placed above the cooking grate...  

If you wanted a Reverse Flow, the stack would be placed above the firebox, just above the cooking grate....  

A Jambo, the fire enters the cooking chamber above the cooking grate and the exhaust is below the cooking grate...  

Dave


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## daveomak

metaldoctor21 said:


> I did run the calculations and everything is what it's supposed to be. *Another thing I noticed is that when I put charcoal in the cooking chamber to use it for direct heat the coals will go out. *I have the charcoal on a tray about 1.5" from the bottom so air can flow under them, but they won't stay lit. That is another reason why I am assuming it is a flow problem.





metaldoctor21 said:


> You are correct on the jambo configuration. I was just trying to give an idea on how my exhaust was because I didn't have any pictures posted at that time. I just came up with the dimensions for the pit as I was building it. I had a family friend who was my smoker expert helping me, but he past away due to cancer before I was able to finish my pit in the spring. I built my fire box bigger, so I could store more charcoal in their for a longer burn time.


It's no big deal....  I often think one thing and type something totally different...  If that's what you did.... we must be related...


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## daveomak

*I did run the calculations and everything is what it's supposed to be.*

One last question..... what calculator did you use......    Dave


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## metaldoctor21

It is kind of a mixture of different things I have looked at.  The friend who was helping me was from Colorado and I am from Illinois.  I decided one day I want to learn to start smoking things and I knew I could build it, but designing it was my weak point.  I built it without physically ever seeing a smoker.   Where I live smoking isn't very big, so try to go to cook offs and snoop around wasn't an option.   My friend was giving me some pointers over the phone.  He had been in several cook offs, so he was my best bet for info.  What would have to be different for charcoal to stay lit under the cooking grate?  Just curious.  Trying to learn everything I can.  I really appreciate the help I am getting so far.  Thanks everyone.


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## metaldoctor21

Feldon


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## metaldoctor21

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\outl0\strokewidth0 \strokec2 Link to BBQ Pit Calculator}


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## sqwib

metaldoctor21 said:


> Yes smoke does come out the inlet hole. Also when I open the firebox door smoke will flow right out of the fire box.


I thought so!

Seems like your drafting from the inlet... I think you will see an improvement with the fire grate above the inlet hole


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## sqwib

metaldoctor21 said:


> I have some more photos I will try and post this evening. I am trying to post them from my phone and am having a problem getting them to load. Will moving the stack up or up and a couple inches from the end have an effect on anything?


I would not modify anything just yet.


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## daveomak

I see the problem with the calculations....  With a firebox at 241% of recommended, and all the rest of the calculations based on the firebox, the calculations think the cook chamber is 241% bigger than it actually is......    

Dave


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## metaldoctor21

Fire box side of cooking chamber












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## daveomak

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## metaldoctor21

DaveOmak said:


> There are many designs for smokers......   What style was your original thought....  It seems to be a mix of different designed smokers....
> 
> I notice you have no tuning plates, which would be appropriate for that smoker...   Then the stack "plenum" would be placed above the cooking grate...
> If you wanted a Reverse Flow, the stack would be placed above the firebox, just above the cooking grate....
> 
> A Jambo, the fire enters the cooking chamber above the cooking grate and the exhaust is below the cooking grate...
> 
> Dave



If I try to use any type of tuning plate it really kills off any flow I have and I can't get the other end of the smoker to get any heat.


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## metaldoctor21

SQWIB said:


> I thought so!
> 
> Seems like your drafting from the inlet... I think you will see an improvement with the fire grate above the inlet hole



I tried running the pit with the grate completely above the inlet and it still didn't seem to change much.  I still have a lot of heat at the fire box end about 450-500 degrees at one point and I struggled to get up to 200-225 degrees at the other end.  It took me at least an hour to get 200-225 degrees at the exhaust end.  I did have to raise the grate up pretty high in the fire box to get above the inlet.  I am not sure if that would effect anything.


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## metaldoctor21

Running with fire box door cracked open and grate raise












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## metaldoctor21

Fire box door cracked open with grate raised












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## metaldoctor21

Fire box door cracked open and grate raised












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## metaldoctor21

Grate Raised












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## metaldoctor21

Grate Raised












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## metaldoctor21

​


DaveOmak said:


> I see the problem with the calculations....  With a firebox at 241% of recommended, and all the rest of the calculations based on the firebox, the calculations think the cook chamber is 241% bigger than it actually is......
> 
> 
> Dave



So do I need to change something to get the correct calculates for the actual size of my pit?


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## daveomak

Post #9 has the calculations for the CC size, I think...  I can't get feldon's to open this morning.....  I wouldn't change any thing on your smoker except......  Move the stack over the FB.... Install a RF plate...  then install a choke plate on top of the stack because it is over sized...

That would be the simple, easy way to make a great smoker....    

Before any of that is done, Check with SQWIB and Ribwizzard for their input....   I could be off base here... 3 opinions are better than one especially considering the work involved....

Since the smoker you have is an assembly of several different styles, I would go with a more conventional style....  Ignore the numbers.... this drawing was for jmud....  And some theory has improved upon this design, since it was drawn...   Dave













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## metaldoctor21

If my inlet hole, fire box to cooking chamber, and exhaust stack are all to large would this cause me to draw to much.  Thus losing all my heat at the other end.  I have a 3" stack 24" long that I can bolt on.  I can close the internal damper from the fire box to cooking chamber down some.  Then block off part of my inlet hole.  I did notice when I ran my pit last night with the charcoal grate above the inlet hole that my exhaust stack got so hot that I could hardly touch it.  I did close my fire box to cooker damper down and was able to get my pit within 50 degrees end to end, but it was a struggle to get the exhaust end up to 225 degrees.  I also adjusted the damper on my stack from full open to almost closed and anywhere in between, but it didn't seem to bring the heat up on that end any.


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## sqwib

I'm camping right now but when I get back I'm going to go over everything again. I would say no you do not have proper draft because smoke is coming out of the Inlet. The draft would literally pull the flame. You can also look into a deflector plate.
I'll check Monday.













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## gary s

With the grate raised in the firebox, and tuning plates removed does it work and draw properly. If still having problems I would do what Dave suggested and convert to a Reverse Flow.

If the tuning plates are removed I don't see why it would not draw correctly ?

Gary


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## metaldoctor21

Finished Product

View media item 258283


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## sqwib

metaldoctor21 said:


> Finished Product
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> View media item 258283


Does that mean everything is working fine?


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## metaldoctor21

SQWIB said:


> Does that mean everything is working fine?



No still having the same issue we have been talking about.  That is just the picture of what it looks like all painted.


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## metaldoctor21

SQWIB said:


> Does that mean everything is working fine?



I painted it before I ever did a test run.  I guess I should have waited to make sure everything worked first in case I need to modify it.  I didn't want you to think I just painted it over the weekend even though it wasn't working properly.


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## sqwib

I see smoke from the stack. That's a good sign. Any pics of the type of fire you had in the firebox?


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## sqwib

metaldoctor21 said:


> Fire box door cracked open with grate raised
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smoke shouldn't be exiting the inlet
I'm just reviewing your photos again


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## metaldoctor21

SQWIB said:


> I see smoke from the stack. That's a good sign. Any pics of the type of fire you had in the firebox?



Just this one.












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## sqwib

DaveOmak said:


> Doc, morning...... VERY NICE smoker........  I like it.....  Where did you get those dimensions from....  did you take them from another Jambo smoker ??     Using the Feldon's calc, your FB is 241% of recommended which should not pose a problem...  FB air inlet is large...   I would plug the top half and try it...     Also, the configuration of the smoker, I don't see any way charcoal will stay lit under the food grate....   Does Jambo say their smokers will work with charcoal under the food grate ??  And I can't remember for sure but, I think Jambo FB/CC opening is above the food grate.... and the exhaust is below the food grate.....  I could be mixing that up with another smoker...   getting too old to remember it all....
> In the link, is what I came up with for a SFB smoker, which is similar in design to yours....
> Link]http://feldoncentral.com/bbqcalculator.html?cc=16,36,0,0,0,0,7234.56,2411.52&fb=10,14,18,0,0,2520.00,2411.52,104.5&ch=3,126.00,17.83&fi=0,0,5,7.56,0.39&fc=5.07,7.16,20.16]Link to BBQ Pit Calculator[/url]
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I think I see a potential problem in photo #1 although I would think this would be a minor issue
Is there a piece of the firebox protruding from the top into the inlet?


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## metaldoctor21

SQWIB said:


> I think I see a potential problem in photo #1 although I would think this would be a minor issue
> Is there a piece of the firebox protruding from the top into the inlet?















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It is part of my adjustable baffle plate from fire box to cooker.


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## ribwizzard

I kind of skipped through the thread and just read half the posts and looked at the pics, so excuse me if I repeat anything already tried,

But that air intake/vent/baffle.....is it threaded in? Can you remove it?  If so, take it off and run the fire with the grate at the same possition as the last pic you posted above. From what I see, with good airflow, as long as your not loosing the heat from around your cooking chamber door, that thing should work.

After removeing the vent cap, if it still doesnt come to temp, place a small fan blowing towards the intake and let us know what that does, if anything.

Id like to see a pic of the fire too.


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## metaldoctor21

Ribwizzard said:


> I kind of skipped through the thread and just read half the posts and looked at the pics, so excuse me if I repeat anything already tried,
> 
> But that air intake/vent/baffle.....is it threaded in? Can you remove it?  If so, take it off and run the fire with the grate at the same possition as the last pic you posted above. From what I see, with good airflow, as long as your not loosing the heat from around your cooking chamber door, that thing should work.
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The intake baffle is threaded in.  I will remove it and try to run it again with the grate above the intake hole.  
I have taken and blown air into the intake hole and it brings the pit right up to temp like it is supposed to.
I am using royal oak lump charcoal and I usually start with one full chimeny of charcoal.  Then I will put some wood chunks in.  I will get some pictures of the fire for you guys.


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## ribwizzard

Well, with only one intake, that vent design might not be the best.


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## gary s

This really seams strange.  Since we are trying different things, one more thought. I assume you have a drain pipe for grease, is it open or closed? The reason I asked on one of the smokers we built an RF unless the drain was open we experienced similar problems, open it up and it started drawing and heating like it was supposed to.   Just a thought

Gary


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## ribwizzard

we need to get that to run with the grate at this level 













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So as you have enough room for a decent fire. You might start thinking about how you would like to get air under the vent where its at. I can tell by your work your a tinkerer.


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## metaldoctor21

gary s said:


> This really seams strange.  Since we are trying different things, one more thought. I assume you have a drain pipe for grease, is it open or closed? The reason I asked on one of the smokers we built an RF unless the drain was open we experienced similar problems, open it up and it started drawing and heating like it was supposed to.   Just a thought
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I have a ball valve on my grease drain, so I will give that a try.  I also have a drain in the bottom and in the center of the fire box.  Maybe I will open that up while it is running and see if that does anything to my airflow.


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## metaldoctor21

Ribwizzard said:


> Well, with only one intake, that vent design might not be the best.



So your thinking get rid of one big hole and go with maybe two or three smaller holes spread out across the bottom as low as I can get them.


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## sqwib

metaldoctor21 said:


> So your thinking get rid of one big hole and go with maybe two or three smaller holes spread out across the bottom as low as I can get them.


No keep that hole, Rib is saying to get air underneath your the fire, some folks will use a vent above the fire as well to give them better control off the heat.

My grate is 4" above the bottom of my firebox and, with 2" holes, this leaves room for accumulative ash so it don't block the holes.













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Also a smoother transition into the cooking chamber helps.













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## sqwib

SQWIB said:


> That is a beauty.
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> Hey can you do me  favor and temporarily raise your grate above the intake and try again, I would love to see if that helps.
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> Everything else looks good, I would prefer the stack outlet at the top of the tank but thats just me.
> 
> Hey Ribwizzard, think you can help us out here?





Ribwizzard said:


> we need to get that to run with the grate at this level
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That is the game plan, he moved the grate up as a test to see if it would draft better as the only inlet hole is above the fire.

In one of the pics you can see smoke pouring out of the inlet.

Rib, I think elongating the hole would help, oh and remove the baffle/damper thingy.

I wonder if the heat is being trapped up at the top by the baffle or lip of the firebox, (refer to my firebox inlet pic)


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## gary s

Here are some pic's of a Jambo build    Not mine !!                    You can see how high the firebox is mounted and where the openings are located













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## sqwib

This has been driving me nuts... the more I think about it I have to lean towards the opening to the cooking chamber being the problem, especially after the test that was done by moving the grate above the air inlet and looking at my build and notes a hundred times.

I have run mine with all vents closed with the exception of one and it still maintained a good temp and draw.

If you close the air inlet completely, build a good fire on the grate at the level it was originally and leave the firebox door open...What happens?

If it's still a problem with heat I would suggest the following.

Open up the cook chamber hole (remove the baffle thingy)
air intakes underneath the fire grate.
With that done, If you are getting draft and everything appears to work with the exception of the heat being optimal I would suggest

Burning splits.
That's where I would start.


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## metaldoctor21

SQWIB said:


> This has been driving me nuts... the more I think about it I have to lean towards the opening to the cooking chamber being the problem, especially after the test that was done by moving the grate above the air inlet and looking at my build and notes a hundred times.
> I have run mine with all vents closed with the exception of one and it still maintained a good temp and draw.
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> If you close the air inlet completely, build a good fire on the grate at the level it was originally and leave the firebox door open...What happens?
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> If it's still a problem with heat I would suggest the following.
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> Open up the cook chamber hole (remove the baffle thingy)
> air intakes underneath the fire grate.
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> With that done, If you are getting draft and everything appears to work with the exception of the heat being optimal I would suggest
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> Burning splits.
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> That's where I would start.



If I build a fire, close the intake, fully open, partially open, or just crack the fire box door I lose all my heat and smoke out the fire box door.


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## ribwizzard

There is not much differential in height from your firebox intake to the cooking chamber opening. so I think its part of the problem getting a good draft going. Leaving the grate low and adding a vent to the bottom I believe may help. The air needs to run more verticle and get more rise inside the firebox to get a good draft going. Right now, its running almost horizontal,  and its not like you could put a check valve or anything to keep it flowing in one direction, all you can do is increase height differential.   You said when you put a fan there is came right up to temp......

Sqwib, Dave, are all of the opening sizes up to snuff?


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## metaldoctor21

Here are some better pictures of my fire box to cooking chamber.  I made the baffle just in case I needed to slow down some heat from the fire box.  I also ran the two top holes into 2"x2" square tube that end about halfway into the cooker.  My thought their was to try and move the heat further down the chamber to even it out.  I wonder if this is also giving me poor flow or causing some kind of negative draw.  I think I am going to do what SQWIB said and cut some of this out to open up the flow.












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## ribwizzard

Pics have me even more convinced the firebox is the problem.

Id cut a pie vent in the bottom of the box you have, then scab another section to the bottom to hold a ash pan,  Then drop your grate down low.  Or you could just cut a square hole out of the bottom and weld your grate right into that hole, then fab a 3 or 4 inch extention to add to the bottom with a front slide vent. . Either way, you wont have to make a new door .

Once again, you said blowing air through the vent got it going!!!


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## metaldoctor21

Ribwizzard said:


> Pics have me even more convinced the firebox is the problem.
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> Id cut a pie vent in the bottom of the box you have, then scab another section to the bottom to hold a ash pan,  Then drop your grate down low.  Or you could just cut a square hole out of the bottom and weld your grate right into that hole, then fab a 3 or 4 inch extention to add to the bottom with a front slide vent. . Either way, you wont have to make a new door .
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I am going to block off the top half of my intake hole and open up the drain I have underneath the fire box and run it that way.  That should kind of simulate what you are talking about.


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## ribwizzard

How big a drain hole is it?


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## metaldoctor21

The drain hole is 1 1/2" diameter.  I am going to block off the top half of this intake hole.  That will get my intake pretty low and with the hole underneath the box.  I figure the drain hole is probably a little small and the door intake is a little higher than you are discussing, but I figured it would somewhat simulate it and I could see if their was any improvement.













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## metaldoctor21

Here are some pictures of the fire.  I have also made the opening between the fire box and cooking chamber larger like SQWIB recommended.  I was able to get the pit up to 400 degrees before I started to back it down.  That is huge improvement.  I am heading in the right direction.  Now that I have a little better flow I did notice some smoke coming out my cooking chamber door.  I am going to have to try and seal that up a little better.  I also need to come up with a deflector plate and or tuning plates to redirect some of the heat coming from the larger opening.  I also opened up the drain on the bottom of the fire box while it was running and it made a noticeable jump in heat.  I may have to change my intake setup to something like Ribwizard recommended.  I jumped back and forth from a 3" stack to a 4" stack and did not see any change between the two.  I blocked of the top half of my intake hole and it kept my temp down, so I opened it back up.  I opened up my grease drain on the exhaust end and that didn't make a noticeable change either.  So it looks like a larger cooking chamber to fire box opening, deflector plate or tuning plates, seal door better, and move intake as low as possible.













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## gary s

Wow. you certainly have had your share of problems and issues. Maybe these mod;s and changes will get it where it needs to be. Hope so.

Gary


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## metaldoctor21

I just wanted to tell everyone thank you for all the help over the last week.  I have really learned a lot and happy to be headed in the right direction.


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## gary s

Let us know how it turns out.

Gary


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## sqwib

metaldoctor21 said:


> Here are some pictures of the fire. I have also made the opening between the fire box and cooking chamber larger like SQWIB recommended. I was able to get the pit up to 400 degrees before I started to back it down. That is huge improvement. I am heading in the right direction. Now that I have a little better flow I did notice some smoke coming out my cooking chamber door. I am going to have to try and seal that up a little better. I also need to come up with a deflector plate and or tuning plates to redirect some of the heat coming from the larger opening. I also opened up the drain on the bottom of the fire box while it was running and it made a noticeable jump in heat. I may have to change my intake setup to something like Ribwizard recommended. I jumped back and forth from a 3" stack to a 4" stack and did not see any change between the two. I blocked of the top half of my intake hole and it kept my temp down, so I opened it back up. I opened up my grease drain on the exhaust end and that didn't make a noticeable change either. So it looks like a larger cooking chamber to fire box opening, deflector plate or tuning plates, seal door better, *and move intake as low as possible.*
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Just place the intakes below the grate level no need to go on the bottom of the firebox. I think you would have more control over vents on the side or the door as opposed to the bottom.


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## metaldoctor21

SQWIB said:


> Just place the intakes below the grate level no need to go on the bottom of the firebox. I think you would have more control over vents on the side or the door as opposed to the bottom.



I just now saw your post after I had made a bunch of modification.  My fault for not checking back, but I already cut the vents in the bottom of the fire box.


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## metaldoctor21

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## metaldoctor21

I ran the pit up to 465 degrees evenly across the pit for the first time.  In one of the pictures you can actually see the flame being pulled into the cooking chamber.  We have made huge progress.  It is finally drafting correctly.  The only thing I haven't done yet is seal the door better and make a handle to operate the new intake easier.  The only problem I have now is when I close the intake to less than a quarter open.  From a quarter open to full open it drafts awesome.  Anything less then that and I lose all my heat at the exhaust end.  The lowest I can get the pit to run evenly is about 300 degrees.  If I dial down the intake any less than a quarter I loss about 75 degrees at the exhaust end almost instantly.


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## metaldoctor21

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This is what my fire looked like while I was running 300 degrees.


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## ribwizzard

putting the pie vent directly under the center of your fire makes a huge difference. Where you will also see the advantage is on windy days, where as there will be less effect from the wind. Ive seen fireboxes with side vents actually have the wind stall the fire due to the draft it creates.


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## gary s

Looking good

Gary


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## sqwib

metaldoctor21 said:


> I ran the pit up to 465 degrees evenly across the pit for the first time. In one of the pictures *you can actually see the flame being pulled into the cooking chamber*. We have made huge progress. It is finally drafting correctly. The only thing I haven't done yet is seal the door better and make a handle to operate the new intake easier. The only problem I have now is when I close the intake to less than a quarter open. From a quarter open to full open it drafts awesome. Anything less then that and I lose all my heat at the exhaust end. The lowest I can get the pit to run evenly is about 300 degrees. If I dial down the intake any less than a quarter I loss about 75 degrees at the exhaust end almost instantly.


Now that's what I'm talking about













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## sqwib

Ribwizzard said:


> putting the pie vent directly under the center of your fire makes a huge difference. Where you will also see the advantage is on windy days, where as there will be less effect from the wind. Ive seen fireboxes with side vents actually have the wind stall the fire due to the draft it creates.


How does it work as a cleanout?, sounds like it may have a double bonus?

Piped inlets , reduce this effect dramatically adding valves helps even more.


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## metaldoctor21

Sorry to keep bothering everyone, but the only way I can keep my draw going is to have my inlet vent a third of the way open.  At this point my fire gets way to hot and I can't keep the temp down in the cooking chamber.  It runs above 375 degrees at this point.  Closing the intake any further causes me to lose my draw and lose heat at the exhaust end.  Any suggestions?  I am guessing that I need to learn to build the right size fire with the intake open a third of the way to give me proper temperature.  Just wanted to make sure I wasn't missing anything else that would cause a problem.


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## metaldoctor21

I understand that heat rises, but when I raise the exhaust end of my smoker I can get the heat to even out at lower temps.  I am able to get down to 225-250 degrees across the pit when doing this.  If I were to move my exhaust to the top of my pit  would this improve my draft.  I am not sure if raising the exhaust end is simulating moving my exhaust up.  If I Iet the exhaust end back down I have to been around 325-350 degrees to get the heat even.  If I have to move my exhaust I could always go reverse flow as well.  I am not sure if either will make a difference, but I am running out of things to modify.  The exhaust stack location is the only thing I haven changed.


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## sqwib

metaldoctor21 said:


> I understand that heat rises, but when I raise the exhaust end of my smoker I can get the heat to even out at lower temps. I am able to get down to *225-250 degrees across the pit* when doing this. If I were to move my exhaust to the top of my pit would this improve my draft. I am not sure if raising the exhaust end is simulating moving my exhaust up. If I Iet the exhaust end back down* I have to been around 325-350 degrees to get the heat even*. If I have to move my exhaust I could always go reverse flow as well. I am not sure if either will make a difference, but I am running out of things to modify. The exhaust stack location is the only thing I haven changed.


To be honest, I'm not sure what you want.

At the risk of sounding like a smart a$$ It's not an oven.


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## gary s

Looking at the picture of your stack location and you CC to FB opening, I am thinking moving the stack up might help. Looks like you were going for the Jambo style. If you look at his, the firebox is attached very high up, the heat and smoke actually travel over the top and down to the stack opening. Just an observation

Gary


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## ribwizzard

Get your firebox straightened out like I suggested,  once you have the air flowing at the right speed, you will gain more control over your temp..


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## metaldoctor21

SQWIB said:


> To be honest, I'm not sure what you want.
> At the risk of sounding like a smart a$$ It's not an oven.



Maybe I am just bad at explaining what is going on.  With the intake moved under the fire and the opening from firebox to cooking chamber bigger I am getting a good draft.  To get that good draft my intake has to be halfway open to full open.  This causes my fire to be very hot.  Even with a very small fire.  That is then making my cooking chamber to hot to cook on.  It runs at 315 degrees and up at that point.  If I close the intake anymore to try and cool down the fire I lose my draft and all my heat stays in the firebox.  Hope that is a little better.  I really do appreciate everyone's help and I want to say thanks again.


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## sqwib

how are you operating the vent that is above the fire?


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## sqwib

The only thing I can think of... if I understand whats going on??

Is to add the stack directly to the top of the pit... I can't think of anything else.

If you can't place it on top, raise it as high as you can on the side.

But before you make any more mods, get some more advice, because to be quite honest, this is starting to baffle me.


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## gary s

Again, looking at your picture of the stack, I would move it as high up as you can

Gary


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## ribwizzard

In the original pictures you posted, it looked like you had an adjustable dampner from the firebox to the cooking chamber...

is it still there?

If so, what happens when you close that back up some?


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## metaldoctor21

Ribwizzard said:


> In the original pictures you posted, it looked like you had an adjustable dampner from the firebox to the cooking chamber...
> 
> is it still there?
> 
> If so, what happens when you close that back up some?



I already cut the damper out.  I can shear up a couple random size pieces of steel to temperarely close down that opening some and see what it does.  Should I start by blocking the lower portion of the opening or the upper portion of the opening?


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## metaldoctor21

SQWIB said:


> The only thing I can think of... if I understand whats going on??
> Is to add the stack directly to the top of the pit... I can't think of anything else.
> If you can't place it on top, raise it as high as you can on the side.
> But before you make any more mods, get some more advice, because to be quite honest, this is starting to baffle me.






gary s said:


> Again, looking at your picture of the stack, I would move it as high up as you can
> 
> Gary



I agree with you guys that I may need to raise my stack up.  Just making sure I have tried everything else first.  I do all my welding at work or at my buddies house, so I am trying to avoid having to haul it somewhere.  Otherwise I would have already moved it.  I think I am about out of options thought.


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## gary s

One other thing I noticed in the pictures the opening from the FB to the CC looks pretty big ?

Gary


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## metaldoctor21

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I ended up switching to a reverse flow smoker.  Everything is now working excellent.  Thank you everyone for your help and a special thanks to Dave for giving me the specs to get my pit switch over and running properly.


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## gary s

Nice job, very nice job

Gary


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