barbecue smoker

[robbie]

I've been feeling like I must be some kind of idiot to have pigs but no smoker, so I finally built one.

I went to the scrap yard and found a 50 gallon propane tank for the oven (that's about the size of a barrel, in case you're wondering), and a freon tank for the fire box. I used a piece of six inch heavy pipe as a duct between the two, and a piece of 4 inch light gauge pipe for the chimney. The chimney used to be a mounting pole for a TV satellite antenna left by the guy I bought my property from. I built the grills from 1/4" rod that I found a big pile of at the scrap yard last year. When you build one of these, the way to build the door is to cut one side, then weld the hinges across this cut, then cut the other three sides. These hinges are pieces of motorcycle chain. Inside there is a heat deflector made from a segment of a barrel. The smoke comes up under it and has to travel to the ends before it comes up into the main chamber, then it goes out the chimney in the middle. This prevents a big hot spot where the smoke comes up. Notice that the chimney is mounted low so the oven will retain heat in the top. The whole thing is mounted on a wagon frame and completed with a barbecue thermometer purchased on ebay and sent all the way from Hong Kong for around ten dollars.

The air inlet on the fire box door has provisions for a sliding draft damper, but I never use it because the hole happens to be exactly the right size to keep it the right temperature. It's easy to use because you stick a piece of meat on the rack, build a fire, then come back and add fuel every 15 minutes until the meat is done. The thermometer allows you to use it just like an oven.

 

[Doc Sprocket]

Nicely done, and thanks for posting it. I have a curiosity about these, and have contemplated building one for some time now.

 

[robbie]

Thanks for the compliment. It looks pretty cool in the photos, but up close it looks a little bit scrappy. I have learned a thing or two about them by building one, so if you're curious don't hesitate to ask questions.

I get the impression that most people who are serious enough to build a smoker tend to start with a 250 gallon tank. I didn't want anything that has to be moved with a truck, so I went with the small tank instead. As it turns out it's big enough for anything I need to do. I can cook two or three briskets at once, or 4 regular size racks of ribs. Last week I cooked 10 pounds of chicken and 15 brats and still had room to spare. In case you're curious, we weren't having a party or anything. I just figured I would use the fire while it was there, and I put the leftovers away.

I have a cousin who occasionally does catering jobs. Years ago I helped him fetch a 500 gallon tank out of a cotton field for a grill. We carried it back to town on a too-small trailer, using his little Toyota truck. That was hilarious. Next time I saw it, he had cut several feet out of the middle, and it had lots of doors for food and separate ones for fire. The fires were built on grates that would go up and down on chains. It had one end for hot grilling and the other for smoking. It was great. He had to sell it several years later when he needed money. That was an awesome grill, but I wouldn't want to build anything that complicated. I like the little one better.

I've been eating a lot more barbecue lately. It's too hot to cook indoors this summer anyway. Now I've become a connoisseur of different types of wood. I have a list of important design tips that I will pass on if you are interested in building a smoker. Just let me know.

 

[OzFab]

That DIY to perfection, everything used to be something else, good job

 

[souperman000]

Are inviting us for a DIYGK Barbeque?

That's pretty cool. Did you have plans or some guidelines or something or was it all from your head?

 

[robbie]

I did a bit of web research first, including some good youtube videos. Most of what I saw was for big tanks, so I just adapted the design principles to my small tank.

The most important thing I learned was the cross-flow principle. A duct is welded into the bottom of the tank from one end to the other, and the fire box is attached to the bottom of the tank at one end. The hot smoke enters the duct at that end and comes out at the other end of the tank. Then it has to turn around and go the full length of the tank again to get to the chimney, which is above the fire box. This design distributes the heat evenly and prevents hot spots.

I could have built my smoker that way, but I figured a smaller unit would be OK with a simplified design. I get the same effect with the fire duct in the middle and a removable heat deflector. Distributing the heat is one of the two major points, and placing the chimney inlet at about the midline of the chamber rather than at the top is the other major thing. As long as you get that right, your smoker should work pretty well.

There are some other general points I learned from my mistakes. I have been heating with wood for over ten years, so I should have known how to build my duct connections. When you put stove pipe together you always put the top piece into the bottom one rather than the other way around, so if you get dripping condensation and creosote it will drip inside the pipe and end up back in the fire. Likewise on a smoker you should always build it so that grease and sludge drips into the fire. Unfortunately I didn't think of that at first, so I cut a hole in the bottom of my tank and put the fire duct into it, rather than welding the duct to the bottom of the tank and cutting a hole in the middle of it. As a result, I get dripping grease around my duct where there are defects in my welds.

My fire box is mounted at one end rather than in the middle, just because I thought it looked cool and I wanted to tend the fire at the end rather than in the middle. I should have built a fire box right in the middle so the sludge would drip right into the fire. Also, on my smoker the end above the fire is always a bit hotter than the other. This isn't really a bad thing because I can put the bigger pieces of chicken at the hotter end, but if you want consistency put your fire in the middle, right under the duct. Also, it will draw better if it's vertical. My fire really never gets going until the tank heats up enough to start drawing hard. For that reason alone I'm going to cut the fire box off and build a new one in the middle. When I do that I'll also build a new duct with a slightly bigger pipe if I can find one, and completely cover the hole in the bottom of the tank to eliminate external dripping.

I have a similar issue with my chimney. I built a 90 degree joint in the pipe and welded it to a round hole that happened to already be in the tank and was exactly the right size. There's a short horizontal segment of pipe about 6 inches long that collects black oil. A better design would have an oval hole in the back of the tank with the chimney pipe inserted and extending down to the mid line of the tank. This way no sludge could collect in the pipe.

My sister and brother in law visited and had smoked chicken with us last month. They were impressed enough that I decided to build one for them. I found another tank at the scrap yard, but this one is 39 gallons instead of 50. You can't really tell by looking at it. The dimensions are all within an inch or two. But there are tons of brackets and doohickeys on the new tank. I want to make theirs look nicer because they have a lovely home, unlike mine, so I'll have to cut all that junk off and grind everything until it's pretty. I'll post photos when I get that project going. It will have all of the improvements I mentioned.

 

[robbie]

By the way, if you come to Missouri I will definitely make you something good for dinner.

 

[OzFab]

Are inviting us for a DIYGK Barbeque?

That's pretty cool. Did you have plans or some guidelines or something or was it all from your head?

By the way, if you come to Missouri I will definitely make you something good for dinner.

I'm afraid I must decline; I can't really warrant $2500 in airfares to attend a barbecue

 

[souperman000]

I'm afraid I must decline; I can't really warrant $2500 in airfares to attend a barbecue

That's fine...More for me!

 

[ChrisT]

Interesting build.
Do you just burn wood and what's the best type to use on these things then?
Kind of curious as I built a double barrel wood burner at work, it's got a hot plate on the fire box and now I'm thinking I could convert the top one into a smoker....

 

[robbie]

That looks promising. It looks like you could add a door and a grill to the top one. You should be able to figure out how to cook something right just by watching it, but a thermometer is even more helpful. The only problem is that whoever built that thing for heating may not appreciate all the grease that collects in the chimney.

There are a few different kinds of traditional barbecue woods. In Texas they use mesquite in the south, pecan in the east, and oak in the north. Here in the midwest oak and hickory are popular, although excessive hickory makes everything taste like smoked bacon. A lot of folks like to add apple wood, which tastes really good. My wife picked up a big chunk of it at the orchard near our house. Smart guy, selling his tree trimmings now. I've started noticing the difference between the different kinds of oak. I heard that walnut is really good for sausage, so I tried it. It's a strong flavor but very good. It's overpowering if you use it on something mild like chicken.

Anyway, my favorite now is oak with about 5 to 10% apple wood.

 

[Doc Sprocket]

I have come to really like hickory and mesquite smoke for flavouring. I have a little cast iron box I put the chips into, over the coals on my charcoal grill.

As far as building a smoker goes, I have been thinking of using a steel 55-gallon drum as the basis.

 

[robbie]

That would work. I think most smokers are built with propane tanks because they last forever. If you make the firebox out of something more robust and vent it into the barrel, it should last a long time.

Also, there are barrels of varying quality. We have fun shooting holes into new trash barrels with a .22. Sometimes the bullet goes in one side and comes out the other. I got some heavy barrels last year, and when we set one of them up for burning trash the bullets went in one side and only dented the other. The smashed bullets that we found in the bottom of the barrel were kind of fun.

 

[robbie]

Chris, you're a pretty smart guy, so give this some thought. Sometimes I think the meat is a little bit over-smoked by the time it's cooked properly. Also, I think a Canadian smoking meat in a barrel in the winter would be a really busy guy. I wonder how much wood you would have to burn to keep the barrel from cooling off. Both of these problems could be overcome by building an insulated smoker.

I've seen smokers online built from giant terra cotta pots, but even a giant pot isn't very big. What about a barrel in a barrel with an air gap for insulation? You could keep something like that at 300 degrees pretty easily even in January.

 

[souperman000]

Out west Oak is the prime wood for some Tri-Tip.

 

[Doc Sprocket]

Well- there's really some food for thought here, thanks Robbie. It's will take some time to set this in motion, as I have a project list longer than my arm, and thanks to this little health glitch, have lost an entire month of possible build time before the weather turns to crap...

 

[frodo]

i have builta couple of smokers...that said...here is a tasty recipe for your smoker
i call it "smoken a fatty"
2 lbs bulk sausage...put into a 1 gallon zip lock, lay flat and flatten out the sausage in the bag. [bag is used to just form patty] chill in fridge to make meat firm
place on a peice of tin foil. cut the zip lock bag leaving a nicely formed slab of sausage
place on the sausage...anything you want.. i use bacon roll up the bacon in the sausage like a roll. seal with the foil. place in smoker....2 hrs. cut and serve on a bun or bisket....
buffalo farts....jalapinos stuffred with scallions and cream cheese.
scoop out the seeds. discard or use , as you perfer. i use. i like hot
mix chopped scallions and cheesed with seeds split jalapino stuff secure with tooth pick. put on smoker beside your meat. munch on em while waitiung on brisket
....
gravy....if you use a water smoker. dip 2 cups of your smoker water out
1/4 cup butter 1/4 flour into a castiron skillet. mix and stir constantly for 5 minutes. if dry add a little smoker water...cook
add smoker water to cooked flour [rue] stir constantly and cook for 15 minutes..

 

[robbie]

The jalapenos sound delicious. My wife saw some really nice ones at the store and had to buy them, even though she doesn't eat them. She also brought home a bunch of cream cheese. I'll have to try this.

I made 110 pounds of bulk sausage this spring when we butchered a 500 pound boar. I stored it in zip bags at 2 pounds each. My favorite thing to do is take this right out of the freezer and put it on the grill frozen. 2 hours later, smoked sausage meatloaf.

 

[robbie]

Out west Oak is the prime wood for some Tri-Tip.

What exactly is Tri-Tip?

 

[robbie]

Well- there's really some food for thought here, thanks Robbie. It's will take some time to set this in motion, as I have a project list longer than my arm, and thanks to this little health glitch, have lost an entire month of possible build time before the weather turns to crap...

I did some eyeball measuring, and it looks as if the 50 gallon propane tank would fit into a barrel but wouldn't have much of an air gap. The 39 gallon propane tank would fit nicely with a useful air gap. Keep your eyes open for one about that size. These are very old propane tanks that mount horizontally on the ground just like the modern ones and are proportioned nicely. The newer vertical mount tanks seem too long and skinny. I think a guy with your welding skills would be able to build an oven that floats inside a barrel, with a door that has the inner and outer skin moving as one.

One other design improvement that I'm going to make on my smoker is a double chimney. It currently has just the right amount of draft to keep the fire going perfectly, but it takes a while to heat up. While its warming up it pulses instead of drafting nicely and there is so much thick smoke you can hardly see anything. More air would fix everything.

The chimney is a 4 inch pipe. I want to change that to two 4 inch pipes mounted about 6 inches apart. The fire box will have a large vent as well, so the whole thing can be opened up for lighting and warming up. Then one chimney will be capped and the inlet will be set for cooking. If it works well I'll use the same design on my sister's smoker.

The original chimney is built from an old TV antenna mount, and I have just enough for two of them. For the second smoker I have a piece of 4 inch truck exhaust pipe, which is pretty much the same thing.