Air in versus air out, How many holes?

[FlyFishnElker]

Hi Yall,

This is my first time posting so bare with me...

I'm building a UDS and am kinda a nerd when it comes to put things together. My plan is to have a UDS that I can smoke around 225-250 then have the option to open er' up to cook at 350-400 (I'm thinking like for tailgating burgers, brats, chicken that kinda thing.)

So far I have two 55gal drums. One that will be the cooker and the second I have cut the bottom 1/3 off at the bevel to make a lid. The lid sits rather nicely on the top of the cooker drum and seems to have a great seal. I also made the charcoal basket it is 12" deep by 18" in dia. and sits 2" off the bottom. I will use some scrap metal to guard the coals from grease that drips off. My total UDS is about 46" tall. I have three trays and possible at time be smoking/cooking a lot of meat!! I'll post pics once I figure out how haha.

BUT NOW THE QUESTION,
I need to know the number of holes, size, and pattern to drill in order to smoke at 200 then ripe er' up to 400.

I was think 4- 1" holes at the bottom which allows for 3.16 sqin of area which air can flow in. Then 8- 1/2" holes on the top which allows for 1.6 sqin of air to escape.

Is this enough exhaust? Any recommendation for intake/ exhaust combos?

 

[Pigeater]

Welcome FlyFishnElker!

When I built my first UDS, I got most of the info from here:

https://www.bbq-brethren.com/forum/showthread.php?t=23436

It covers everything from material sourcing, cleaning, construction, seasoning, and usage.

There is some debate over the best location/diameter/quantity of intake and exhaust holes.
I can say i've had great success using 3 each 1"Ø intake holes (ID of pipe nipple is less than 1") spaced evenly around the base of my drum, and 1 each 6" tall riser pipe exhaust screwed into the lid bung hole.
I cap two of the intakes with a pipe cap, and have a ball valve on the third. I don't restrict the exhaust in any way.
My UDS cruises at 225º with only the ball valve intake wide open (and the other two intakes capped), and I can achieve 450º-500º with everything wide open.

Good luck with your build. You will probably enjoy smoking with it!

 

[frankenfab]

Set yourself up with more intake and exhaust than you think you need in square inches, and have the ability to dampen it.

 

[SmittyJonz]

I've made several -first ones I did 3 1" intakes with a 2.5" center exhaust - last cpl I put a single 2" pipe intake and single 2.5" exhaust in lid center with dampers.......I used auto exhaust pipe but these are nice:

https://udsparts.com/dampers/air-inlets.html

https://udsparts.com/dampers/exhaust-dampers.html

 

[pharp]

Hi Yall,

This is my first time posting so bare with me...

I'm building a UDS and am kinda a nerd when it comes to put things together. My plan is to have a UDS that I can smoke around 225-250 then have the option to open er' up to cook at 350-400 (I'm thinking like for tailgating burgers, brats, chicken that kinda thing.)

So far I have two 55gal drums. One that will be the cooker and the second I have cut the bottom 1/3 off at the bevel to make a lid. The lid sits rather nicely on the top of the cooker drum and seems to have a great seal. I also made the charcoal basket it is 12" deep by 18" in dia. and sits 2" off the bottom. I will use some scrap metal to guard the coals from grease that drips off. My total UDS is about 46" tall. I have three trays and possible at time be smoking/cooking a lot of meat!! I'll post pics once I figure out how haha.

BUT NOW THE QUESTION,
I need to know the number of holes, size, and pattern to drill in order to smoke at 200 then ripe er' up to 400.

I was think 4- 1" holes at the bottom which allows for 3.16 sqin of area which air can flow in. Then 8- 1/2" holes on the top which allows for 1.6 sqin of air to escape.

Is this enough exhaust? Any recommendation for intake/ exhaust combos?

Drill a two inch hole in the top and put a damper. I used a flat metal disc I found in the HVAC section at lowes for $2.

 

[SmittyJonz]