Opa's Recirculating Smoker

Discussion in 'DIY / Self Sufficiency' started by Opa, Nov 4, 2012.

  1. Opa

    Opa Opa-wan Chickenobi

    May 11, 2008
    Howell Michigan
    One of the oldest methods for preserving meat, fish, and fowl is smoking. Learning how to properly brine and having the proper equipment can greatly improve your success in bring a properly cured and smoked product to your table.
    I’ve been smoking various food items for over 40 years and have used just about every type of smoker available and one common fault I observed with all of them is that the temperature is hotter the closer you are to the heat source.
    Even commercially available smokers costing over $4000 still work on the same principle as a $100 Little Chief smoker, heat and smoke from below rises up and around the meat, then out the top vent. I think that this lends itself to uneven cooking; which would explain why a long sausage hung in a smoker will be drier at one end.

    A few years ago I decided to build a new smoker using an upright freezer and while removing all of the plastic panels and pieces I realized the solution. Most of today’s freezers are frost free. This is accomplished with a re-circulating fan and an internal chamber that allows air to be moved from the top to the bottom of the box. By using that same principle I could re-circulate both the heat and the smoke in the box thereby making the entire box the same temperature, not unlike a convection oven.

    After removing all of the plastic from the freezer, I took careful measurements of the freezer;s interior then went to a local heating contractor and had him bend sheet metal to completely reline the box. I also picked up a piece of sheet metal for the door interior side. This cost me approximately $120.

    Before installing the new liner I drilled a small whole thru the back wall of the freezer at the bottom of the re-circulation chamber which was about 18” from the bottom of the cabinet. The location of the top of the re-circulation chamber was careful noted and it’s location marked on the new liner. A hole was then made in the liner to match the hole at the top of the re-circulation chamber. Next I installed the 3 walls, ceiling, floor, and door panel.

    Obviously you will need a smokestack and a damper to control the rate with which smoke and heat are allowed to escape and a 4” Smoke stack and damper will cost $13

     So a 4” hole was drilled in the top and the damper/stack was installed. To facilitate opening and closing of the damper I replaced the wing nut with a connecting nut, a thread rod, and a new handle. 

    The door will need a seal to keep the heat and smoke in your cabinet. I found that a D shaped heat resistant gasket with a pressure sensitive tape on it to be the best bet.
    Enough gasket to seal the door is about $15

    A good temperature control & sensor is a must and will cost you about $125. 
    You will also need a temperature probe and gauge to monitor the inside temperature of the box. Cost $60 

    An Indicator lamp to tell you when unit is heating will run an additional $3 

    Housing for control and gauge 

    Cost $45.99 Not a must but it certainly makes for a more professional looking unit and much easier to install and protect parts. The total cost of purchasing the controls is $235.


    A pre-assembled control box, heat control & sensor, control indicator light, temperature gauge & probe can be purchased for $265.99 but is $36 that could be used towards the other parts and wiring the controls was quite simple.

    I would also recommend an additional temperature gauge with a 12” probe to monitor the inside temperature and to cross check the temperature probe in the control box cost $20


    Having a separate box for your smoke chamber allows you to add sawdust or wood chips without ever having to open the smoker. I had an old aluminum mailbox but I’m sure if you were to check at a scrap metal yard you would be able to find something comparable for $10
    You’ll need a hot plate to heat the sawdust $10 

    A electric dryer element to provide the heat source for the oven will cost $80

    This is attached to the back wall of the cabinet approximately 6” from the floor and is braced to the sides of the cabinet. The end with the electrical connections is considered to be the back. I bent and installed a piece of sheet metal over the top to act as a drip shield. A large cookie sheet is placed on the floor to catch drippings. Shield and pan are lined with aluminum foil before use.

    A 90 degree elbow is attached to the front.
    A thru hole is drilled in the back wall of the cabinet located at the center of the dryer heating element. A 90 degree elbow, sized to match the outflow side of the blower motor dictates the size of this hole. The elbow is then installed on the outside of the cabinet.
    At previously drilled hole, at the bottom of the re-circulation chamber on the back of the smoker, you enlarge the hole to match the intake side of one of the blower motors and attach it to the smoker. One end of a Flex pipe is connected to the outflow side of the blower and the other end is attached to installed elbow. This will draw air from the top of the cabinet, thru the internal re-circulation chamber, and then push it back into the cabinet, blowing across the dryer heating element.

    Oft time you can get this motors from a heating contractor salavaged from an old furnace.


    This photo show the fan motor installed at bottom of recirculation chamber with pipe connecting to opening for dryer heating element. Fan draws heat and smoke from chamber and redirects it across heating element. A metal shroud covers motor for weather proofing. Ten guage power cord, garden hose holder, junction box for electrical connections.

    A second blower motor is installed in the smoke box to draw smoke from the smoke box and push it into the smoker cabinet.

    Pipe from smoke box entering cabinet near floor
    Two electric blower motors will cost $156 

    You will need some type of latch to hold the door closed and you should be able to get something for $10 for the pair.


    I built a simple frame to place the freezer and smoke box on and installed two fixed wheels and two swivel wheels so that I could move the smoker. Lumber will cost about $10 and the wheels about $30.
    After a strong wind blew the entire unit across my driveway I decided to add 4 hinged blocks of scrap 2x4 that could be folded down to lift the wheels off the ground. 

    The assembled unit is quite heavy so I made a simple lifting lever to make that task easier.


    You simply place under edge, push down, and frame is lifted high enough to flip down hinged blocks.

    The finished smoker 

    Total approximate cost $700

    Or you could just say the heck with it and buy a commercial built unit for $4800 but it wouldn’t work as effectively since in wouldn’t re-circulate the heat and smoke
    Last edited: Nov 4, 2012
  2. 1muttsfan

    1muttsfan Free Ranging

    Mar 26, 2011
    Upper Peninsula Michigan
    Thank you Opa! What a work of culinary art.
  3. punk-a-doodle

    punk-a-doodle Songster

    Apr 15, 2011
    So neat, thanks for sharing!
  4. Snowypinesridge

    Snowypinesridge In the Brooder

    Sep 24, 2012
    Newport, WA
    My Coop
    Very Nice!
  5. leghornfarm

    leghornfarm In the Brooder

    Mar 9, 2012
    This is nice, may give it a try.
  6. wyoDreamer

    wyoDreamer Crowing

    Nov 10, 2010
    NE Wisconsin
    Just printed this out for the Hubby. He is so dicouraged trying to find the right smoker, maybe this will inspire him to make one he likes.

    Thanks for the post.

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