Building a Smoker Pit - EVERYTHING You Need to Know!

With numerous designs out there, tackling your first smoker pit project can be a bit daunting. Through a quick search online you'll find an array of options and features to choose from. In this Instructable, I'll focus on a "backyard" size smoker pit that I built in my personal shop. I will cover all of the traditional do's & don'ts, the myths & methods, unique features to consider, and ultimately what has worked successfully for my own smoker builds.

Step 1: Smoker Pit Basics

Before tackling your own smoker build, it's good to have a basic understanding of how they work.

Types of Smokers

There are several different styles out there. One of the most common is a log burning offset smoker (also known as a horizontal smoker). This style utilizes a firebox mounted to the side of the main cooking chamber - see attached diagram. These typically come in two different operating methods:

Traditional - The heat and smoke generated in the firebox travels into the cooking chamber and across the meat before exiting out of the exhaust stack.
Reverse flow - The heat and smoke generated in the firebox travels into a segregated lower portion of the cooking chamber before making a turn and "reversing flow" over your meat and out the exhaust stack. Note that the location of the stack differs compared to the traditional style.

Other common smoker types include vertical, drum, electric, pellet, and kettle style.

Smokers also come in a wide variety of sizes from full trailers to smaller single brisket versions. The most common is the "backyard" size smoker that you'll find at your local hardware store.

Operation

An ideal temperature for your cooking chamber is a steady 200 to 250 degrees F. Once you have a good fire burning, you want to let the cooking chamber level out to a steady temperature before placing your meat inside. Maintaining a consistent temperature is key and requires periodic adjustment of the fire. You can dial in your temperature by adjusting the airflow via the firebox air intake.

Smoking meat is a low and slow process. In the case of a brisket, it's an all day (or all night!) affair. One of the best methods to monitor internal temperature of your meat is with a temperature probe that does not require you to open the smoker lid. Opening the lid is a quick way to release stored heat - something you want to avoid during a cook.

Composition

When it comes to smoker efficiency, material thickness definitely plays role. A smoker stamped from thin gauge sheet metal versus one built from 1/4in thick steel will perform drastically different. A thin walled smoker will require much more intervention to maintain the desired temperature for cooking not to mention a lot more wood as well. A thicker shell will hold a steadier temperature and retain heat better all while using less fire wood.

Overall, there are a lot of variables involved when operating any style of smoker pit. Even with a thin gauge smoker, you can produce great results with the right attention and intervention throughout the cook. Electric and pellet smokers require much less attention as these styles use automated means to maintain the desired cooking temperature. For me, I'm a fan of the traditional wood burning versions.

Step 2: Planning and Design

A few initial questions should be answered:

What style of pit do you want to build? - Purely dependent on preference and sometimes space limitations. You can't go wrong with a basic offset/horizontal smoker.

How large of a pit should you build? - I like to consider how many briskets I foresee needing to cook at once. A 36 inch long cooking chamber on a horizontal smoker is usually plenty of space for a home smoker pit.

What equipment and tools do you have available? - Keep in mind that these pits can get very heavy especially when using thicker materials. You'll want to ensure you have the right equipment to weld and handle the thickness and weight chosen. You'll need to plan your build carefully and consider how you will turn and maneuver the pit during manufacturing.

CAD Modeling:

A great way to plan your build is through the use of CAD software such as Fusion360. This will allow you to play with all of the design parameters and ultimately facilitate a smoother physical build process. Attached are some images of the CAD model for my backyard smoker.

Other factors to consider:

Portable or stationary - Weight adds up quickly on these pits so a good set of wheels is a common feature. The wheels are typically placed near the center of the length of the pit making it easier to pick up and maneuver from a weight distribution standpoint.

Reverse or traditional flow (in the case of offset smokers) - I've built and used both styles with success. With a reverse flow smoker, your meat stays a bit more isolated from the open flame which reduces the chances of overheating your meat during uncontrolled flare ups. Reverse flows can be a bit more difficult to clean depending on how you build in your baffle plate. In the end, either style will work just fine. I generally prefer to stick with traditional style smokers.

Thickness of material - This will be driven by your budget and your fabrication capabilities. Thinner materials will be cheaper and easier to work with (especially if you only have some basic metalworking tools). However, thicker materials will retain heat better. If you're going to go through the trouble of making your own pit, I recommend using at least 3/16in thick materials which will yield a long lasting and efficient final product.

Types of materials - Often times large diameter pipes (around 18 to 24in in diameter and at least 3/16in thick) are used to build backyard smokers. Other options included used air compressor tanks or even used propane tanks. In the case of propane tanks, be sure to evacuate all gas using a water purge before cutting into the tank. Some individuals even opt to build their pits by bending plate steel. In the end, any of the previously mentioned materials will work. Much of the decision relies on what you have at your disposal. If using older materials, you'll want to ensure they aren't heavily corroded as this can affect the overall lifespan of your pit. If available and if you have the right fabrication equipment, some folks even build their pits out of stainless steel.

Overall, you want to ensure your CAD model accounts for each and every detail of your pit. Taking some time during the design stage can save you a lot of time and effort later on.

Step 3: Commencing Fabrication

With your CAD model established, you can now begin the build process. I personally prefer to have all of my parts and materials on hand before beginning a project. This means everything from the raw steel to the hinges for the doors.

I have the luxury of a CNC plasma cutter in my personal shop which allowed me to get a bit more creative and efficient in the design and fabrication of my pit. If you don't have access to a CNC, you can easily accomplish the job with basic fabrication tools.

I designed my pit such that a large majority of the components would cut out from a single sheet of 1/4 inch thick steel. I used an 18 inch diameter 1/4 inch thick pipe for the cooking chamber. I fabricated the firebox from raw plate. Attached are some photos of the CNC cut parts and the raw pipe.

Step 4: Fabrication Continued - Leg Assemblies

I approached my build by first fabricating sub-components as follows:

The leg assemblies
The cooking chamber
The firebox

For this step, I'll focus in on the leg assemblies.

Cut from 1/4 inch thick plate, the legs were designed with integral pipe end caps. Using some right angle guides, the CNC cut parts were mated up and welded with ease. Round pipe or square tubing can also be used to create simple leg assemblies or base structures without the need for a CNC machine.

You'll notice that one of my leg assemblies is shorter than the other. The shorter assembly accounts for the height of the wheels that I planned to add later.

Step 5: Fabrication Continued - Cooking Chamber

For the cooking chamber, I began by cutting the pipe section to about a 36in length and mapped out the door location.

Cutting out the cooking chamber door:

Often times, cutting the door can be a bit tricky due to residual stresses present within the steel. If you directly cut out the door from the pipe, the door section may spring out into a flatter shape (a larger radius) resulting in poor fitment when closed. This doesn't always happen but is a risk to keep in mind. There are a few methods to combat and or resolve this:

You can directly cut out the door and take your chances. If the door does spring flatter, some folks have successfully heated and bent it back into shape. This can be difficult though and I do not recommend it.
You can heat the steel pipe using an oxy-fuel torch in an effort to relieve the residual stresses before cutting out the door.
You can weld some temporary brace bars to the interior of the door, cut it out, weld on your door trim pieces, attach your hinges, and then cut the temporary brace bars out. The idea here is that the heat input from welding on the trim and the hinges will help to relieve the stresses in the steel and prevent spring back in the door.
You can partially cut out the door by leaving certain sections connected to the main pipe in order to hold the door shape. You can then weld on your trim and hinges and then cut out the remainder of the door.
You can add permanent bracing to the inside of the door before fully cutting it out.

I have used methods 3 through 5 above with success. For this particular pit, I decided to use method 5 and weld in some permanent bracing. There are theories out there that the bracing can negatively affect the flow of heat through the cooking chamber. After using pits with and without door bracing, I can say that I've never noticed a difference in cooking quality. I did however try to minimize the height of my braces in an effort to make them less intrusive.

Attached are some photos of the cutting and bracing process I employed.

Step 6: Fabrication Continued - the Firebox

I built my firebox using 1/4in thick steel plate. Another option is to use a section of pipe. Either method will work just fine. I added a top lid and grilling surface to the inside of my firebox for added functionality.

Some folks choose to insulate their fireboxes. Having built and used both insulated and non-insulated versions, I can certainly attest that insulation does have advantages. With insulation, you'll retain heat better, use less wood, and have an easier time maintaining your desired temp. However, you can still yield just as good results with a regular un-insulated box and the right level of attention throughout the cook. For this build, I opted to forego the insulation.

One additional aspect to keep in mind is the size of your firebox. Firewood typically comes in a 16in length. Ensuring your firebox can handle standard lengths of wood will make operating your pit a bit simpler.

Step 7: Fabrication Continued - Assembly

Now that your legs, cook chamber, and firebox are substantially complete you can begin assembling these components. This is when your pit really starts to take shape.

As previously mentioned, these parts can get heavy so you'll want to take some care during this stage. I used my forklift to assist. However, with the right planning you can easily assemble your pit alone by hand, with an engine hoist, or with the help of some friends.

For now, I recommend tacking your components together just enough so they hold securely. You can perform final welding during later stages.

While mating your firebox to the cooking chamber, be sure to use a level to keep both components aligned and true.

Step 8: Fabrication Continued - Final Details and Unique Features

With the main structure of your pit assembled and standing, you can begin work on all of the auxiliary components and features. These include the doors, hinges, exhaust stack, door stops, trim work, cooking grates, wheels, handles, thermometers, air vents, and more.

For this pit, I included a few unique features:

Stainless steel cooking grates - For the main cook chamber as well as the firebox, I opted to build my cooking grates out of 304 stainless steel. This ensures a lifetime of use and prevents any corrosion on the surface that the meat directly contacts. Plain steel grates will work just fine as well but you do run the risk of them corroding especially if you infrequently use your pit.

Solid rubber wheels - These can be a bit pricier than pneumatic versions but will never go flat and don't require any air pressure.

Smoke control baffle - Between my firebox and cooking chamber, I included a rotating baffle that you can control from an external handle. This baffle can increase or reduce the size of the opening between the firebox and cook chamber. This is simply an added means to control the temperature. I added this feature as more of an experiment than a necessity.

Extended length handle - To make the pit as easy as possible to move, I built an extended length handle for maximum leverage. To keep the handle out of the way, I designed it to fold down.

Adjustable height grill - 4 slotted mounting rails allow for an adjustable height grate within the firebox. This provides added flexibility when using the pit as a grill only.

Stay cool handles - I mounted my handles using round rod with hitch pins. This allows me to replace the handle with a variety of different materials. I used some round aluminum pipe to start with.

Easy access exhaust cap - Using round rod, I created an extended control rod for the cap on top of the exhaust stack. This brought the control handle down to a more comfortable level. I also included a latch for locking the cap closed.

See attached photos of all the features mentioned above.

Step 9: The Finished Product

After some clean up and coating, my pit was ready for final inspection and testing.

Since the inside of your pit remains as raw steel, you'll want to use a wire brush to clean off any corrosion or mill scale on the interior and blow it out well with compressed air.

The exterior should be coated in a high heat paint (readily available at your local hardware store). Traditional paints will not hold up to the heat exposure.

Step 10: Burning and Testing

One of the first things you'll want to do to any brand new pit is a good hot burnout. I like to build a large fire inside the firebox (and sometimes inside the cooking chamber as well) and let the pit get as hot as possible. This will help burn off any debris inside or any chemicals that may be on the raw steel from the factory.

After my burnout, I was ready to throw on some meat. Attached are a few photos of the first trial runs. Works flawlessly!

Hope this was helpful and many thanks for checking out my build!