AMNPS and smokehouse mods!

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pops6927

Gone but not forgotten. RIP
Original poster
OTBS Member
SMF Premier Member
Jul 23, 2008
7,245
1,219
Fort Worth, Tx.
I've done quite a few smokes with both the AMNS and the AMNPS and have had great success, but 2 things pop up:  1) during hot smoking, how do I keep the product from flaming, and 2) providing enough draft (airflow) to keep it burning.  

I wondered about an external application:

Went to Home Depot, looked at all the vent stuff and nothing clicked.  Walking out,  I noticed a display... it clicked... what if.....

I exterior mount the unit inside a Metal Mailbox!



Mount it, drill holes in bottom, screw and seal box to smokehouse, use a 2" hole drill through the box and plywood, then seal around it and in the hole between the box and plywood.  Adjust your draft by opening the door a little at a time, plus the holes already in the bottom of the box.  Enclosed, metal, adjustable draft, exterior, no flame-up worries!  If it's 110° outside, you probably ought to reconsider "cold" smoking anyways, lol.  But,for either cold or hot smoking, not a problem!  Just run the propane burner inside if you want to hot smoke without fear of catching the pellets on fire. No propane for cold smoking.  If you want, toss a chunk in the iron frying pan too for extra goodness, or fruitwood sticks, etc.





Fits perfect!

Hmmm... maybe a 2" hole in the bottom, with a flap to open or close with.... like an electric circle box cover plate with 1 screw it to swivel on...

Now, do I want a mailbox on the outside of my smokehouse?  ABSOLUTELY!

Mad Scientist Smokaholic Pops over and out for now, until I test it out!
 
Well, first step, mod the mailbox.  Drilled a 2½" hole with a holesaw in the back of the box, then a 1¾" hole in the front.  I attached the cutout from the back to the vent hole in front with a nut and  bolt after tracing the outline of the smaller hole on the cutout so I could center it properly, then simply bent up the edge a little to provide a grip to swivel it.  It was weird drilling everything with the opposite hand!

From the front:



From the back:



The two little holes I tried mounting a piece of plywood inside to aid the holesaw but it was too rickety, so I just went at it with the holesaw through the metal and it worked fine!  I'll cover those holes with a little caulk, no problem.

Of course, I'm just guessing for the input and output draft holes; may be to much (but have an adjustable flap on the front to cut it down) or, too little.  If so, I can open the door a bit too, just don't want it to draft out instead of in!  But, pushing the unit all the way to the back should direct the draft to where I want it to go.  Have to stop and go to dinner with the older son and grandkids!  Will continue tomorow and hopefully complete it and test it, have a date with some buckboard bacon Saturday!

Think I might put a piece of ceramic tile under the unit so it won't heat up the metal box that much; non-conductive.
 
Alrighty by crikey...! lol...

Got the mailbox mounted; I cut 6" long pieces of 1x4 (7/8" x 3½") to put in the bottom of the mailbox, covering up all holes to control the draft, screwing them in on the sides, and lining up the boards to get at least one screw in on each side, plus to get proper spacing for the mounting holes underneath so there was solid wood to mount to (a bit of planning, eh?, lol, plus keeping the back of the bracket flush w/box:



Then, test fitted the unit to the smokehouse, lining up where I wanted the draft hole to be (figured just above the drip pans, where I'd set it when inside), then drilled the hole in the side, centering it.

Then, re-align the hole with the mailbox and mark where the screws will go into the bottom of the bracket (held the mailbox with a 1x1 length inside it, lining up the two holes while marking the screw holes with a Sharpie[emoji]174[/emoji]).  

Brought it inside and caulked the back of it:



Then brought it out and mounted it.  Took about 4 tries, kept dropping the drill, the screw off the drillbit, moving the box, etc.  Should use two people, believe me, or at least one with two good hands, lol!  But, got it mounted!



from the back:

"YOU GOT MAIL!"



From inside the box:



Inside the smokehouse:



Of course, light it up and test  it!  (drum roll..)

It's Smokin'!



Pouring out!



and out the top vent!



So, Cold Smoking is a success!  YAY!  Now, how about hot smoking?

Well, that took some experimenting with!  I'd had the draft on the bottom of the smokehouse where I normally had it.  The Cold Smoking entered the smokehouse from the side with no problem, no more adjusting needed.  But, Hot Smoking... different story.  Tried different positions, putting lit end in first nearest the entrance hole, or the reverse, in the middle of the mailbox,  cutting the 1x1 in half lengthwise to raise the unit for more draft underneath, and so on.  It was like with the heat on, the hot air rising did not pull the smoke into the smokehouse box, which I thought it would even moreso.  Wrong!  I fiddled and faddled with this and that, then suddenly realized, it didn't have a reason to pull the air in, the bottom draft was doing that!  So, **click** - close the bottom draft.  Now where is the flame from the propane burner going to get air from to keep burning...??? You guessed it, through the mailbox, creating the draft through there and likewise pull the smoke in with it!  I'm checking it as it is going, I'll report further on what it's doing, plus on Saturday when I'm smoking meat with it!  Stay tuned!
 
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 Well, I figured it needed more area to pull the smoke in, so I drilled from inside the smokehouse two more holes:



then replaced my makeshift props with a better one:



Hopefully that will allow more airflow up from the bottom plus through it too; if not, I'll have to put the two verticals on some metal strips or something and eliminate the horizontal board.

But, got the AMNPS going with two rows lit and put it in the box, started the propane and shut the bottom vent and here's the result:



Thin blue is rolling and temp in climbing!  It is drafting great and coming out the output vent like it should!  But, no heat in the mailbox that will catch the pellets on fire, and plenty of draft to keep it from going out!  I think if I did it again I'd just remove the back of the mailbox and cut out a hole just a hair smaller than it to be able to seal it and it would work just fine!  The front vent it open all the way too.

This is the initial start; let's see what happens as it goes on!

Just took a pic of the money end, hopefully it shows the smoke going into the smokehouse:



It is drafting so much better, no buildup in the mailbox now, all being sucked into the smokehouse immediately!  Exactly what I wanted, and the draft keeps the pellet embers smoldering so no fear of it going out!  And, no heat buildup in the mailbox, no combustion on the pellets either, draft must not be that great to get them to ignite.   If it does, then I can close the small circle in front down some to adjust the draft.

I just sealed around the bottom vent on the smokehouse and it increased the draw through the mailbox and likewise the amount of smoke exiting through the top vent!  I'll do a few more smokes, but may just take out the bottom vent and board it and seal it up!

Temp reached 241° in the smokehouse and I got a flame in the pellets.  Very simple, pull the wood carriage out and snuff out the flames.  While at it I added more pellets and slid it back in, then turned down the propane a bit and now it's at 220° and nice smoke rolling and no flaming.  The best part is tending to it outside the smokehouse, makes it very simple and can see it flaming easily and only had to open the burner door to see to adjust the flame a bit lower.  Close it back up, draw starts immediately and smoke rolling out the output vent!  I think I'm getting to like this very much!
 
Smoke is rolling out, esp. since caulking the bottom vent!



Oh... and the aroma?  WOW!  Cannot wait to try it!
 
It has finished!:  I'm also using Todd Johnson's newest product, the Pitmaster's Choice Pellets, a combination of Hickory, Cherry and Maple - http://www.smokingmeatforums.com/t/119176/pitmasters-blend-pellets-now-available:



Isn't that just a beautiful color??  And the taste?  INDESCRIBABLE!  Absolutely delicious!  You can taste the subtle flavors of the mix of woods, yet they blend together beautifully!

The mailbox did GOOD!  Especially since we had 40 mph winds all day long!  Once getting the draft going thru the box, it was excellent!  We did ignite at 241°, but it was at the height of the wild winds, too; I'm sure that was part of it.  Otherwise it worked good!  I will need to redesign the bottom carraige of wood; it impeded the airlflow on the sides where the holes were, so starting it in the middle produced better results, but that's a fine-tuner to accomplish; possibly riveted-on rails instead.

Definitely a success!  And it kept the AMNPS from overheating, and provided enough oxygen, and directed the airflow, and did not interfere with dripping meats snuffing it out, etc.!  If I opened the door, the smoke would come whooshing out the mailbox as the draw was interrupted.  Bingo, as soon as the door closed it would be airtight again and the smoke would immediately dissipate and resume exiting out the top vent!  I think I'm gonna like this alot!
 
Pops--that's what I call ingenuity!

I would love to hear the neighbors when they look over the fence and see a mailbox attached to your smoke house.
icon_biggrin.gif
 
Heh heh heh... that's a killer... my neighbors are Vietnamese or Cambodian or something like that... they don't speak English at all, just nod their heads, and their 'back yard' has no grass but piles of junk everywhere, and they've constructed a shanty in the back yard, along with an old 10' satellite dish with stuff hanging off it.... they should not even notice a mailbox on my smoker, they're not tall enough to look over the fence anyways, lol!

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Pops--that's what I call ingenuity!

I would love to hear the neighbors when they look over the fence and see a mailbox attached to your smoke house.
icon_biggrin.gif
 
BTW, I caught heck from the wife; she and my youngest son helped me with this all along the way (except when I could try to do it myself and mess up).  She's re-read this and I never would ask for help, but now they get mad when I don't or mention that I didn't.  I apologize for not saying so.  pride makes you stupid.  I did hang the bacon on the hook though, was able to do it with the other hand!  She hung it in the smokehouse for me.  Sorry wife, you're too good to me!
 
Well, now that it's set up, I can do some smoking on my own!  Got a tray of Portabella sliced mushrooms in the smoker right now, covers w ¼ sheet pan w/grate on top!  These were a big hit at graduation so I can reproduce them here again and not have to spend any propane money!  I'll get pics when I check them in an hour or so, then when done!  
 
Here's a quick shot, the smoker is smoking just fine with the Pitmaster pellets and the inside temp is 74°, outside temperature 71°, so temp gradient is minor.  It smells good!

a363ef3a_001.jpg
 
The mailbox did GOOD!  Especially since we had 40 mph winds all day long!  Once getting the draft going thru the box, it was excellent!  We did ignite at 241°, but it was at the height of the wild winds, too; I'm sure that was part of it.  Otherwise it worked good!  I will need to redesign the bottom carraige of wood; it impeded the airlflow on the sides where the holes were, so starting it in the middle produced better results, but that's a fine-tuner to accomplish; possibly riveted-on rails instead.
A  thought that I had was to make a venturi. If the combustion air for the propane was necked down a bit the flow increases creating a bit if a vacuum.  Holes placed in the low pressure area would then suck in the smoke from the pellets.  My thinking is that giving the pellets a independent combustion air supply would lessen the chances of the pellets igniting.
 
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