Dedicated Cold Smoker Build

Discussion in 'Other Builds' started by jckdanls 07, Sep 11, 2011.

  1. jckdanls 07

    jckdanls 07 Master of the Pit Group Lead OTBS Member

    OK...  Looking for opinions and thoughts for a cold smoker I want to make.

        Have been thinking about this for a month or so. My plan Is to build a cold smoker with 1" thick insulation board that has the "tin foil" (don't know what else to call it) siding on both sides. The smokeing chamber will be somewhere around 2'x4'x2'. All corners will be taped together with A/C foil tape. The door should be snug enuff to just close it. Will cut some dado's in the side walls and insert aluminum U channel (siliconed in) to slide the racks into and out of. It will have a 3" exuast duct out the back at the top.

              Should I build a seperate little "Side Fire Box" for the AMNPS with a 4" dryer duct connecting the 2 together and use a little P/C fan ? My thinking for this would be to keep any heat generated from the AMNPS out of the smoke chamber to keep temps down. Maybe the "Side Fire Box" will have enuff air flow with just a 3 or 4 inch intake vent ?

           Please let me know what y'all think..  Good, Bad, Or Indifferent

  2. smokinal

    smokinal Smoking Guru Staff Member Moderator OTBS Member ★ Lifetime Premier ★

    It sounds like a great plan.

    I like the side firebox with the pc fan.
  3. tjohnson

    tjohnson Smoking Guru Staff Member Moderator Insider OTBS Member SMF Premier Member

    I would try it without the sidebox first.

    The AMNPS will raise the heat inside the box about 15° on cooler days to 20° on hot days.  The only time you really have to worry about it, is when you smoke cheese.  At 100° cheese starts to sweat and can melt.  Smoke during cooler nights or mornings, and you're OK.  Other stuff like bacon can smoke above 100°.

    I like the idea of the foam smoker.  It may be light enough for the wind to take off with it, so you may have to weight down the bottom.  Reminds me of smoking in a cardboard box.

    Take lots of pics and keep us posted!!

  4. roller

    roller Smoking Guru SMF Premier Member

    A true cold smoke has the fire box about 10 to 12 feet away from the smoking chamber with a duct connecting the 2. When the smoke reaches the smoking chamber it is cold.
  5. jckdanls 07

    jckdanls 07 Master of the Pit Group Lead OTBS Member

    Thanks y'all

       I need to finish the wifes project first, brick column light post at the end of the drive way. When thats done (couple of weeks) I'll get started on MY project...

  6. turn4fun

    turn4fun Fire Starter

    I built exactly what you are describing several years ago.  I used a 4'x8' sheet of 3/4" Celotex (rigid orange colored foam with shiny foil on one side and dull foil on the other side).  1 sheet will make a 2' x 2' x 3' tall smoker (including top and bottom) with zero waste. 

    The build couldn't get more simple, all you need is a straight edge and a razor blade.  I cut all of my pieces with a 45º bevel on the edges.  Then I laid them all side by side (bevels and shiny sides down) and taped them all together with foil HVAC tape.  Then it was just a matter of folding the box together and taping in the top and bottom.  The beveled edges allowed everything to lock together very well and kept things square.  For good measure I taped all of the seams on the inside as well.  

    I cut a large door in one of the side panels, again with a 45º bevel around the parameter. This allowed the door to seal well when closed.  I taped all of the exposed edges of foam around the door and the opening.  A single piece of tape along one edge served as the door hinge and I used one or two small pieces of tape to hold the door closed each time I used it. 

    For a vent I used a 3" chimney cap that I fit a damper into.  I just cut a hole and taped it in.  It worked great but in hindsight I think a drop in floor register would have been easier and just as effective.  Thermo probes were simply poked through the sides.

    My intended use for this smoker was for cold smoking sausages.  The sausages were hung from metal rods that were merely poked through one side of the smoker and out the other near the top.  I dug a fire pit in my back yard and buried 6' of 4" pipe.  I cut a hole in the bottom of the smoker and simply placed it over the pipe where it exited the ground.  It worked fantastic.

    I also used it for hot smoking as well.  Over the years I fired it with a small charcoal pan, an electric hot plate and a small propane stove.  All methods worked quite well and it held temp like a dream, even in the winter.  I smoked hundreds of pounds of deer sausage, dozens of trout, a few wild turkeys and a handful of ribs and butts.  Fish and sausage were hung from the rods while other items were placed on a free standing wire rack that I had that fit perfectly inside.

    It lasted about 6 years outdoors, unprotected and survived many storms including a big ice storm and a few tree limbs falling on it.  The best part of it was whenever it got damaged it was super easy to repair with HVAC tape.  I've done other builds since then including a freezer build and an awesome reverse flow, but that little Celotex smoker is still one of my favorites.  One of these days I may have to build another one and run it with an AMNS. 

    I think I am in agreement that the side box is probably not needed.  If the AMNS does get it warmer than you want, you can always put a cake pan full of ice and rock salt inside. 
  7. roller

    roller Smoking Guru SMF Premier Member

    Sounds like a winner !!!!
  8. jckdanls 07

    jckdanls 07 Master of the Pit Group Lead OTBS Member

    Turn, thats exactly the way I was thinking with the 45` cuts and all. I've read the part over and over again about the fire pit with the 4" pipe try'n to figure that out.

    Was the pipe under the pit or just to the edge ? How deep was the pipe buried ? Was it to draw the heat or just the smoke ?  I take it that the draw worked ok or did you use a fan on the exuast side of the smoker to create the draw ? Really appreciate your response to my post, got the wheels turning.


  9. turn4fun

    turn4fun Fire Starter

    Here's a rough sketch of how I set it up.  The drawing is obviously not to scale.

    I only used the in ground pit to do cold smoking in cooler weather, so not much heat transferred.   But, if I really put the wood to it, it would transfer enough heat to run 175º.  My yard has a slope and I dug the pit right on the break.  The pit was about 18" deep and probably 18" square.  I used the lid from a Weber grill to cover it.  The pipe was buried just a few inches under the surface.  There was a 90º elbow on one end with a chimney cap on it and that is all that protruded from the ground. 

    I put a cast iron fire grate from a wood stove on the bottom of the pit, and after the first couple of smokes I ran a second pipe into the bottom of the pit for airflow.   It drafted quite well so I never felt the need to add a fan.  A fan probably would have made it run hotter anyway which would have defeated to purpose of putting the fire pit so far away to begin with.  The nice thing about using the Weber grill lid was if the smoker got a little warmer than I wanted, I could use the vents on the lid to quickly bleed off a little heat without completely killing the draft through the pipe.  

    It's funny, I built it as a disposable unit to smoke a few batches of deer sausage one winter since I was in between "real" smokers at the time.  I never expected that it would work as well or last as long as it did.  I'm a little embarrassed  to tell about it's ultimate demise, but I think it's worth mentioning.  Like I said earlier, I kept it out in the elements for 6 years, so it got beat up and had to be repaired occasionally.  Toward the end of it's life, the bottom had gotten torn up pretty bad in a storm and had to be cut out.  I had to reinforced the bottom edge below the door with a thin strip of wood.  The last time I used it I knew it would be the last smoke, but didn't expect it to end the way it did.  I had it loaded with 20 rainbow trout and was running on a small propane burner.  The smoke went well but I noticed that the strip of wood I put in had started smoldering after a few hours.  When the trout were done I opened the door to shut off the burner.  I closed the door and went in the house to grab a platter to put the fish on.  Apparently, when I opened the door that last time I introduced enough oxygen to allow the wood strip to flash after I closed the door and the little smoker burned to the ground in seconds.  I'm only telling the story to caution you that Celotex is highly flammable.  I'd still feel comfortable running a burner inside of it,  just be careful not to allow an open flame to have direct contact with the material. 
    Last edited: Sep 15, 2011
  10. jckdanls 07

    jckdanls 07 Master of the Pit Group Lead OTBS Member

    Thanks Turn. Thats very interesting, but it seems like a lil more than I wanna mess with. Think I'm just gonna go with the AMNS. Thanks for taking the time and explaining it with a very good drawing to boot. But I will keep it in mind tho for the future.

    Last edited: Sep 15, 2011

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