Lets Build a Smoker

Discussion in 'Propane Smokers' started by hog warden, Nov 3, 2009.

  1. hog warden

    hog warden Smoking Fanatic

    Working on a concept for building an LP gas smoker out of a 55 gallon drum. The intended smokee is a variety of smoked sausages but could escalate into using it for ribs, birds, etc.

    The sausage smoking process is to start with temps in range of 120* to 130* for an hour or so and draft and dampers wide open to dry the sausage. Then medium to heavy smoke is added for a couple hours, at the same temps.....and when the smoke is completed, closing down the draft and dampers and cranking temps up to 160 to 170 degrees until the internal temp of the sausage is 152 degrees. This can take 4 to 6 hours or more, depending on the size of the sausage. During this whole time, smoker temps shouldn't exceed 170 for more than a few minutes. Essentially, what you need is a very precise, low temp oven with potential to add smoke.

    This started with an idea to use my UDS for this, but quickly found out that keeping steady temps in the range of 160* to 170* for hours on end wasn't going to be easy using charcoal or wood. Most small commercial smokers use electric hot plates or gas burners and are relatively small in size. What I should do is chuck the idea of building one and buy a GOSM......but where is the fun in that?

    So here is the plan:

    55 gallon drum (with option to upgrade to an 85 gallon drum).

    LP gas burner (more on this later).

    Racks for hanging sticks or grill.

    Draft/damper control.

    Here is the first prototype:

    Most UDS smokers don't fit the billing of ugly. This one does! It's been burned out, but nothing more. Paint will come later if it works. No loss really, the barrel was free.

    I started out with the small camp stove burner on a 2# bottle, set under the middle of the barrel. Early tests showed it would get the temps up, but that was on a 70 degree day. But during a test smoke when it was 40* F out and the wind blowing, temps maxed out at 120*. I also went through 2 plus bottles on this smoke, so this was not going to work. Damper control might change this. More on this later.

    So I replaced the small burner, which probably has 8,000 BTU max output, with a Bayou Classic cooker, max 160,000 BTU. Supposedly, it will throttle down low enough to simmer a cup of coffee, but not for me. Get that low enough and the wind blows it out.

    But it goes together like this:

    Hole in the bottom of the barrel......note the bricks for the heat baffle to rest on:

    The distance of the baffle to the burner is about 8 inches, so the baffle plate....the lid off a 30 gallon drum......doesn't get hot enough to cause wood chips to smoke at initial smoking temps (less than 130*). So I have considered using a trashed out dutch oven.....the kind without legs:

    A load of chips in this will smolder about 2 to 3 hours. Concern is that grease might get on them, but at these low temps, should not flare up. May if I was smoking a butt or something, with grease and higher temps. The smoke pan needs to be under the baffle for doing this.

    For low tech, I hang sausages on these sticks, which also prop up the lid:

    There is probably a ratio of draft or damper area to box size, but I don't know what that is. Most commercial smokers seem to use a 4 inch plus damper on a small box. The two inch bung hole is roughly 25% the area as a 4 inch hole, which has about 12.5 square inches of area. My method left a gap of 1 inch between the barrel and lid, with a 22 inch diameter......and 69 inch circumference.......or 69 square inches of draft area. All my heat is escaping, yet with the cooker throttled down, I have trouble getting temps down to 125*. Somewhere in there is also the problem of too much heat and air moving through, drying out the sausage too much. So the next step is to devise some internal racks so I can drop the lid a little. Or stick with my first smoke solution, which was a emergency "blanket" draft.....a nasty old wet beach towel:

    What I think I need is a smaller burner. I can buy a 40,000 BTU burner, perhaps mounting it on the same cooker frame?


    A different option was to ditch the cooker and insert the burner inside the barrel. For that, you need a burner and here was an option:


    This is a burner and intake venturi, connected by a variable length of black steel pipe, which could be stuck through the side of the barrel near the bottom. But this is also a 160,000 BTU burner.....too hot. And now you have gas inside the barrel with smoldering wood chips. If the flame goes out and gas continues to flow, you have the makings for a pretty spectacular gas explosion. So one of these designs now has to have a thermocouple with gas shutoff.

    If I (we) get this figured out, maybe I can adapt the design to this barrel:

    That is an 85 gallon heavy steel haz mat drum. Lots of options with this.
  2. evo 9 guy

    evo 9 guy Smoke Blower

    Very interested to see how this thing turns out. Out of curiosity, what is the internal distance from side to side on the 85 gallon drum?
  3. mballi3011

    mballi3011 Smoking Guru OTBS Member SMF Premier Member

    Man when you get this thing figured out your gonna have a great smoker fr sausage and anything at low temps for sure.
  4. dutch

    dutch Smoking Guru Staff Member Administrator Group Lead OTBS Member SMF Premier Member

    An easier solution would be to go with an electric hot plate and a cold smoke generator. That way, propane doesn't have to be used and no risk of having the smoker go BOOM!
  5. hog warden

    hog warden Smoking Fanatic

    ID is 26 inches. Sides are 38 inches. Internal volume BC (Before Contraptions) is roughly 10.8 Cu. Ft. Round.

    By comparison, this smoker by Sausage Mania has about 5.3 Cu. Ft.


    Since this is the basic end product I'm trying to duplicate, you can study it a bit for "rule of thumb" ideas.

    It has a 20,000 BTU burner or 3,750 BTU per Cu. Ft. Round that up to 4,000 BTU / Cu Ft. I'm roughly in the ball park with a 40,000 BTU burner for the big barrel. More than enough for a 55 gallon drum and way overkill with my current 160,000 BTU blaster, unless I can find a way to throttle it back or reject heat. Perhaps just move it off to the side to bleed heat? Could it be that simple?

    The SM smoker has the square shape (as most of these do), which looks to me like they are better able to utilize the internal volume, but I don't know if the square corners cook as even as a round smoker with "smokees" all hung in the middle. Looks like they have two dampers on the sides, level with the burner and smoke pan and a draft on top. Simple dial type. Probably 4 inches.

    My current drum has all the draft it needs with that big hole in the bottom. The damper on top needs some work.

    BTW, the cooker burner designs with venturi don't need outside combustion air. That comes from mixing the air with gas in the venturi. The single burner design I started with is straight propane out of the bottle. It needs an outside combustion air source. And having the bottle that close to stuff inside the barrel means that 2# bottle heats up too much, which is a safety issue. Aside from that, an 8,000 BTU capacity burner heating nearly 7 Cu Ft is a bit small. That little burner been rejected as a heat source.
  6. hog warden

    hog warden Smoking Fanatic

    No BOOM? Where's the fun in that? (From a guy who has played with dynamite......literally).

    Where does one get the hot plate? I can buy replacement heating elements for cookstoves at the local ACE, and the block to wire it, but then I need a rheostat to control it.

    I found an El Cheapo apartment sized hot plate at WalMart, but I don't think it had the ooomph to run this.
  7. waysideranch

    waysideranch Master of the Pit OTBS Member SMF Premier Member

    Cool build. Good luck.
  8. alx

    alx Master of the Pit OTBS Member

    Hog Man I am very interested in same thing.Figured i would have to salvage and customize a electric oven style deal.

    As you said-lets build together.I have been thinking similiar.
  9. hog warden

    hog warden Smoking Fanatic

    For you gassers........or hot plate guys for that matter.......when in use, how much smoke does your smoker smoke?

    I've been playing with various burner options, setups, etc for my ugly drum and finally got it to hold steady temp of 125 for well over an hour, while smoking, but was getting what I considered to be heavy smoke:

    Curious is this is normal. Seems excessive to me. What may be distorting things is that is a 2 inch vent stack. The lid doesn't fit tight so that is leaking too. It's getting less damper than it might seem.

    From what I can tell most electrics, and gassers for that matter, generate smoke by putting a pan of chips or sawdust directly onto the heat source. As in pan directly on the burner, or by using something else really hot like an electric charcoal lighter directly in contact with the wood. That's like red hot. That's pretty much what I was doing but this was the result.

    Look normal to you?
  10. mgnorcal

    mgnorcal Meat Mopper SMF Premier Member

    What was the ambient temp at the time?

    Keep in mind that in cool winter weather you'll be seeing some steam/condensation. That will make the exhaust look different.

    Also, I tend to get TBS only when cooking at higher temp than that.
  11. hog warden

    hog warden Smoking Fanatic

    I'm guessing it was around 60 degrees. The thing that occurred to me is getting smoke by putting wood in contact with hot metal is forcing it. But there is hot enough to smoke and too hot.....about to flame up. I'm seeing the benefits of a fully enclosed, insulated smoker.

    Curious if other smokers using hot plates or gas end up with charcoal or white ash after the smoke? White ash would imply the thing burnt.....the question would be how hot and how fast.

    Shortly after that photo was taken, I snuffed the gas burner, but the chips in the pan kept smoldering at their own pace. I had an additional hour or two of blue smoke, not not thin but heavy because it was captive in the barrel. I don't view that as bad, as this is sausage and not BBQ. Different product and process.

    With this setup, there are a lot of moving parts to balance out. Ambient temps.....low requires more heat and if the burner is the heat source, that means moving the pan farther away to keep get the right temps......warmer means enough heat to get smoke means too much heat from the gas burner. Keeping the burner outside the barrel also causes problems with wind. At these low temps, any wind at all can snuff your flame. Turning out to be harder than I thought it would be. A whole lot more art than science.

    Although it would violate everything that is holy, I'm wondering what would happen if I were to cold smoke my summer sausage over night and cook it the next day? It was 36 this morning. During this time of year, a guy could hang sausage at night with cold smoke and likely be alright.

    The generally accepted practice is to use heat to dry out the casings, but cold smoke isn't entirely cold. It's generated by smoldering chips.......read burning.......which generates some heat. It's not uncommon for the temps to be 10 degrees or more warmer inside the barrel than out. The higher temps lower the relative humidity, which would aid in drying. The process would be to get 3 to 4 hours of cold smoke applied overnight, then cook the following morning. I can regulate temps pretty easy if I don't have to generate smoke in the process.
  12. zapper

    zapper Smoking Fanatic OTBS Member


    Just some thoughts to kick around.

    If the cook chamber was sealed off at the bottom so that no propane flame or gasses could enter the chamber and the bottom of the drum or a reinforced area of the drum bottom was the "Hot spot" for making smoke....maybe reduced risk of BOOM!

    Put a 55 gal drum inside the hazmat drum and insulate the space with formeculite or some kind of high temp insulation

    Make an offset heat exchanger

    Make an offset smoke generator

    The tighter the seal the easier it is to control the temps

    keep us posted
  13. hog warden

    hog warden Smoking Fanatic

    Latest iteration is close to working. Fired it yesterday for a test, and managed to maintain steady temps of 125*, with smoke for over 2 hours. Getting it throttled down that low, with smoke, has been the problem. Looks very similar as before, with subtle changes:

    Same ugly drum. What's changed is the base, which is now a full enclosure so the lip of the drum sits on block all the way around. The only major source of air into the system is through that small opening. Before, with cracks, a puff of wind would snuff my flame.

    Second, bricks holding up the baffle plate are gone, replaced by 1/2" angle iron, which leaves a very small opening through the 8 inch hole in the bottom. Slows down the heat a lot. Getting the heat throttled down has been a problem. But that 40,000 btu burner still has the ooomph to bring it on up to finish the job.

    So in operation, the burner is lit and is running hot enough to stay lit inside that protected area below the drum. It's slightly offset from the hole, heating the drum as much as the air running through the drum, which it also does. In Rytek's book on sausage, he has a section on building smokers where he mentions that all commercial smokers run on gas, and gas pushes a large volume of air through the smoker, helping dry things (offset by the water vapor generated by the burning gas). Heating that entire area below the drum and letting the heated air rise through the drum (vs pumping still burning gas into the drum) gives a better burn. Before, I noticed the odor of unburnt gas coming through the vent stack.

    There is a very fine line between the gas required to heat the drum to 125* vs what it takes to bring it on up to 165*. Less than you would think, and that burner has the ooomph to go to 225* if I want it to.

    Generating the smoke has been another problem. Originally, I thought I could put a burning smudge inside the drum. Not enough oxygen left, so the smoldering chips I like to use for cold smoking kept going out. I tried putting chips on the baffle plate, but to get them hot enough to smoke brought the temps in the barrel up too high (might work for larger pig parts like butts and ribs). Tried putting the plate on the burner, as is done with almost all smokers, but found the difference between hot enough to generate smoke and so hot I got a blast of white smoke, was too close to count on reliably.

    I've tried several versions of the hot plate option......wood smoking from touching hot metal, and I always seem to get a belch of white smoke, or not much at all. It's the charcoal process. Get it too hot and you get a runaway fire going.

    What I settled on so far, and this is not good either, is a one quart paint can with three 5/16" holes drilled in the side about 3/4" from the bottom. Start a few pieces of charcoal, let them get going good and dump enough smoking pellets on top to cover the coals about 3 inches. Less than that and you get a fire. More and it slows the smoke down. But that draws air into the can, the pellets hot smolder, generate a lot of blue smoke from burning and runs about 2 to 3 hours. If I want more smoke, less chips in the can to let it burn faster and fill it up now and then. You need the holes in the bottom of the can for two reasons. First is to control the burn. Second, the burning propane gas creates an oxygen free layer under the barrel that will snuff the coals of a top burning can. There is fresh air along the bottom and all the air being drawn into and through the barrel passes through the opening. Fresh air passing the can will keep it going well.

    The bad part is the can with burning chips is also sitting below the barrel, next to the propane burner. If the flame from my propane burner were to be snuffed, it holds the potential for the big bang. It may be the burn can needs to be isolated off to the side and fed into the opening through a tunnel of bricks, or revert to a hot plate or other smoker generator off to the side. Commercial gas smokers have an offset smoke generator that pumps the smoke into the smoker. So much for simple. [​IMG]

    But as is, I'm not far from giving this inexpensive barrel smoker a shot at the real thing.[​IMG]
  14. jjmrascal

    jjmrascal Smoke Blower

    I am very interested in how this turns out b/c I built a new sausage smoker last year like you did. I cut a second drum in half and use that as a base/fire location. It has a hinged door to close it off and provide access for the fire pan. I have an adjustable intake on it. I, too, found that my hot plate was good for the old smoker but is too small now. I have been using charcoal as a heat source and it works well but maintaining temp is a bear.
    I have been reading up on making it a gasser like you are doing. I plan on it but your posts have made me know about the oxygen free layer and smoking problem. I never thought of that. I will keep reading your results but as it is, your correct burner is 40,000 BTU? I will have to look for one.
  15. hog warden

    hog warden Smoking Fanatic

    Size of burner may actually be more like 55,000 BTU. It's the burner and 10 psi, low pressure regulator (with needle valve) off this guy:


    There is also a 15,000 BTU single burner camp stove option, with similar head design. They sell for under $20. I don't have one, but that's something to consider for doing this with 50* plus ambient temps. The one I have above is still on the margin of being too large.

    As now ready to test, it goes together like this:

    Note the foot long pieces of 1/2" angle iron to hold the baffle plate up.

    Baffle plate, which is the lid off a 30 gallon drum. It has a rim to catch drippings. Not shown is a large stainless steel bowl for a drip pan. It's nearly as big around as the lid.

    Smoke sticks made from some scrap oak lumber. Ripped 1" x 3/4", then rounded over on top. Bottoms are still square so they don't roll around. Plenty of room remaining in the barrel to hang 24 inch summer sausages. Maybe 30 or 40 pounds worth? Brackets are simply 1/8" inch x 1 1/4" flat steel, bolted to the side by bending 1 inch tabs on the end. This bracket will hold smoke sticks or a grill for pork parts. Design was to keep at least 6 or 7 inches of head space at the top. A second set of brackets could be added for another layer for more sausage, butts, ribs, etc. or a big turkey.

    And finally.....I decided it warranted cleaning up, so I busted off the rust with an angle head grinder with wire brush then wiped it down with Crisco and seasoned it a couple times. This took all of 1/4 cup of Crisco and it now has a hard enamel like finish on it. Not nearly as ugly as advertised:
  16. jjmrascal

    jjmrascal Smoke Blower

    As I told you in my previous post, I have been reading up on this and agree that a safety valve / thermocouple is the way to go. I cannot find one anywhere for propane. I have not yet tried an appliance store. Would they sell a setup? I was going to play w/ the idea of a pipe burner set in the base of my smoker under a piece of 1/4" steel plate that I have left over from my tuning plate mod. That way the steel would heat up and act as a damper to temp swings (hopefully).[​IMG]
  17. rod guy

    rod guy Smoke Blower

    I have bought parts like that for my motorhome water heater. Check with an RV dealer.
  18. hog warden

    hog warden Smoking Fanatic

    The pipe burner idea may work. Outside, you have to have protection from the wind. A second barrel bottom may work for that. Sized right, it may even be possible to put it inside the barrel. But again, it's more than heat. Air moving through the system is needed to dry the sausage for smoking. Stagnant hot air and smoke is not the goal.

    These guys sell a number of burners, including the pipe burners (larger ones), but also have the air venturi casting that you screw your own length of black gas pipe into. Make one with fewer holes?


    The burner, pilot and controls from a propane hot water heater may also work. Then there are the burners and controls from a variety of old gas BBQ grills. Lots of options with those.

    Whatever you use, I found that the wind has to be accounted for. Snuffing the flame out on the bottom, and wind chill requiring more heat on cold days on the top (uninsulated barrel).
  19. hog warden

    hog warden Smoking Fanatic

    Finally got a chance to field test the smoker on some summer sausage. Write up for that is here:


    Thoughts? It worked well enough. Here is how it controlled the temps:

    Without a pilot and thermostat to control things, you have to keep an eye on it. Note the change in ambient throughout the day. What that doesn't show is what happened when I went from a dead calm at dawn (first hour of smoking) to a sunrise (solar gain on the black barrel), offset by changes in wind speed (flame was snuffed once at about hour 2.5). Taking those out, the temps stayed close to one temp +/- about 5 degree swings for short periods of time. For no apparent reason (I'm guessing it was caused by wind shifts), the temps would rise of fall for a few minutes, then come back.

    This was a stable, dry heat and smoking with the quart paint can worked well. I had to play with that, but not much on the smoker.

    In short, it's capable of doing what I wanted it to do, which was smoke sausage:
  20. jjmrascal

    jjmrascal Smoke Blower

    Great job! [​IMG]I have never made the cervelat but have looked into before. Glad to know the paint can idea worked out too. I have decided to go with an electric burner for my smoker. I just remember how I rarely had to mess with my old one and I did not have the explosion problem you mentioned with gas. Allied Kenco sells controls for a burner that come with a capilliary tube for feedback but I am going to talk to the local appliance repair place to see if I can make one out of parts more easily available. I will have to wire a 230 Vac outlet but that is no problem since I have an outdoor breaker panel right by where I smoke the sausage. Anyway, great job on the sausage, I can almost taste it from here!

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