Starting a Pitmaker Clone

[anstissk]

Hello all,
I haven't been on the forum in some years but some free time in my schedule opened up and I have been getting back into BBQ and smokers. I am in the process of designing a Pitmaker clone. I have double checked all my calculations, but I was wondering what the implications of my design would be if some of the features were larger than what's needed. For example, my CC volume is 11,222, and the chimney size recommendation is 246 cubic inches. In my design, mine is at ~360 cubic inches. Will I get too much draw? My FB minimum is 3703 cubic inches, mine is coming out to be 4380 cubic inches (I dont really see a problem with this, but maybe there is?). My reverse flow opening in the back of the smoker is 4 sq inches smaller than the recommended formula (dont foresee an issue, please let me know if you think there will be).

Also, bonus question... On the Pitmaker smokers, how are they getting away with only using a 2" ball valve for an air opening? The sq. inches of air needed for mine is coming in at around 11.5 sq. inches. Thank you for your time!

 

[JC in GB]

Wow. That is quite a project. I am interested in following your progress.

As far as the design goes, I am no expert but from what I have gathered, the top vent size is more important than the bottom for cabinet style smokers.

From what I have read, you can control the smoker temp better by using the top vent.

I will be following to see what you come up with.

Ever consider a gravity fed Stump clone?

 

[JC in GB]

Could you change the color of the human model's pants to purple?

 

[anstissk]

Wow. That is quite a project. I am interested in following your progress.

As far as the design goes, I am no expert but from what I have gathered, the top vent size is more important than the bottom for cabinet style smokers.

From what I have read, you can control the smoker temp better by using the top vent.

I will be following to see what you come up with.

Ever consider a gravity fed Stump clone?

I have not considered a stump clone, as I like a little bit of hands on work with feeding the fire and stoking once in a while. I run a WSM currently, the offset I built that is my avatar is no longer in service. Do you have any feedback on the other numbers?

 

[anstissk]

Could you change the color of the human model's pants to purple?

Yes, I can change the pants to whatever color/pattern I choose lol. Im modeling this in Creo as I have access to it for work. I model tooling and such a lot in my career, so whenever I want to design something personal, I just take the laptop home a few nights. I am about to start on prints for the smoker, but I was hoping to get some feedback on the calculations. I still need to finish the interior of the doors to allow for replaceable fire gasket, add a drip blocker on the interior of the door, and finish the interior of the firebox.

 

[JC in GB]

I wish I could help you with this but my strong point is electronics. I am terrible at mechanical engineering.

When you want to add a PID, I can help you.

 

[anstissk]

I wish I could help you with this but my strong point is electronics. I am terrible at mechanical engineering.

When you want to add a PID, I can help you.

Nice, I home brew too so that would be helpful in my set up.

 

[anstissk]

Tonight I got the grates, firebox, valves, water pan drain, deflector plate and handles in. I also did a drip guard on the door interior to protect the door gasket and modeled in a bung for the thermometer. If anyone gets to it, please leave me some feedback on the design as well as the numbers I posted earlier. Im going back and forth between adding a second ball valve for more air inlet sq. inches, but since Pitmaker gets away with one, I would like to keep it clean with a single inlet.

 

[drunkenmeatfist]

I would suggest getting rid of the nerd in the design. I don't like that guy.

 

[JC in GB]

I would suggest getting rid of the nerd in the design. I don't like that guy.

He would be okay if he had purple pants.

 

[JC in GB]

Why not make the ball valve a bit oversized? You can always close it down for less air. All the big cabinet smokers seem to use this ball valve setup.

 

[anstissk]

In my research, all of those smokers utilize a 2" ball valve. According to the calculations, that seems overly small, but theyre still getting away with it.

 

[daveomak]

Smaller valves have a more sensitive air flow control...
The upper valve, is that for secondary air inlet ??? If so, great choice to be able to move air from the firebox to the cook chamber without adding air to the fire....

 

[anstissk]

Smaller valves have a more sensitive air flow control...
The upper valve, is that for secondary air inlet ??? If so, great choice to be able to move air from the firebox to the cook chamber without adding air to the fire....

Sorry I haven’t checked this in a couple weeks, I’m still waiting on the material quote to get back to me. The thought on the upper valve is for a 1” drain from the water pan (304 SS) to outside of the unit to create an easier clean up.