Flow problems with my custom build smoker

[sqwib]

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

 

[sqwib]

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.

 

[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

 

[metaldoctor21]

Fire box side of cooking chamber

image.jpg

• metaldoctor21
• Sep 29, 2013

 

[daveomak]

metaldoctor4.jpg

• daveomak
• Sep 27, 2013

 

[metaldoctor21]

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.

 

[metaldoctor21]

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.

 

[metaldoctor21]

Running with fire box door cracked open and grate raise

image.jpg

• metaldoctor21
• Sep 29, 2013

 

[metaldoctor21]

Fire box door cracked open with grate raised

image.jpg

• metaldoctor21
• Sep 29, 2013

 

[metaldoctor21]

Fire box door cracked open and grate raised

image.jpg

• metaldoctor21
• Sep 29, 2013

 

[metaldoctor21]

Grate Raised

image.jpg

• metaldoctor21
• Sep 29, 2013

 

[metaldoctor21]

Grate Raised

image.jpg

• metaldoctor21
• Sep 29, 2013

 

[metaldoctor21]

​

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?

 

[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

jmud 2 (2).jpg

• daveomak
• Sep 28, 2013

 

[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.

 

[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.

IMG_20130928_100608_551.jpg

• sqwib
• Sep 28, 2013

 

[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

 

[metaldoctor21]

Finished Product

View media item 258283

 

[sqwib]

 
Finished Product

View media item 258283

Does that mean everything is working fine?

 

[metaldoctor21]

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.