My ongoing battle with Masterbuilt 2 door smoker and AMNPS

Discussion in 'Propane Smokers' started by hollowpoint1911, Jul 20, 2015.

  1. I picked up a Masterbuilt Dual Fuel propane 2 door smoker at the beginning of July and after the first few smokes running apple wood chunks in a cast iron pan, I decided to try out a AMNPS pellet tray. The goal was to try and get a longer duration of "unattended" time where I wouldn't have to reload wood chunks since they only last for anywhere from 1 to 1.5 hours.

    After some research, I learned that it isn't recommended to run the AMNPS tray inside the Masterbuilt cook chamber, so I went the "mailbox mod" route which keeps the AMNPS pellet tray in a secondary container and pipes the wood smoke into the cook chamber. Most guys on here use an actual mailbox, but I had a old charcoal grill (Smokey Joe knockoff) that I decided to repurpose for this mod. With some parts from Home Depot, ducting was run from the mini charcoal grill to the Masterbuilt smoker without issue.

    Looks good right? Not turns out that smoke from the AMNPS tray gets sucked down into the propane burner when it's turned on, instead of flowing up through the cooking racks. This means you might see a whiff of "thin blue smoke" out of the top exhaust, but it's maybe 10% of the smoke that's getting piped in from the AMNPS tray. I smoked a Boston butt with this setup and the meat hardly picked up any smoke flavor.

    The next challenge... how do I prevent the propane burner from sucking the wood smoke downward? I tried a bunch of things along the way, and to save you the details I'm currently using a inverted veggie grill basket (full stainless steel piece from Weber) over the propane burner, and a hacked up stainless steel baking skeet sitting on top of the veggie basket acting as a baffle. I'd say 90% of the burner is now blocked off from the cook chamber. I thought that was going to do the trick, so I fired up the AMNPS again to test. Somehow, the smoke still manages to get sucked down or dissipates with this setup, so I start thinking that maybe I need to install another exhaust at the top of the cook chamber to create a stronger draw of air that will suck the smoke up. With this in mind, a 3.5" hole was cut in the top of the box and unfortunately things didn't get better.

    I thought maybe I needed a smoke I threw a extra piece of A/C ducting reducer I had from when I plumbed the charcoal grill "mailbox mod" into the smoker. The reducer was about 8 inches tall...and that did nothing. I thought maybe a taller smoke stack was needed, so I purchased a 2ft long stove pipe. Things seemed to get a little better, but the smoke coming out of the smoker was really thin. Being beyond frustrated at this point, I decided to light the AMNPS tray from both ends for maximum smoke output. Things looked a little better, so I ordered another AMNPS tray from Todd so that I could burn 2 of them at the same time. The charcoal grill needed to be modded a bit to fit 2 AMNPS trays, but that wasn't a huge issue.

    Even though I don't have the 2nd AMNPS tray yet, I decided to test things out yesterday by doing a "quick" smoke with some spare ribs. The AMNPS tray was lit from both ends, spare ribs were cooked at 225F using a 3-2-1 method. The result? Ribs that were hardly smokey... I had "TBS" pouring out of the smoker the whole time, I have no idea why the food isn't getting good smoke flavor! In addition to the ribs, I also threw on a batch of ABTs and those didn't really pick up a smokey flavor either.

    I'm now at a loss of where to go from here. I have a few hundred bucks in modifications poured into this smoker (with a 2nd AMNPS tray and 20lbs of pellets incoming from Todd, to join 20lbs I already have), and it seems like trying to get a pellet tray to work with this propane smoker for hot smoke is a huge bust. I'm pretty much out of ideas at this point on other things I could try to do to remedy the problem.
  2. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    You must REALLY like a strong smokey flavor! [​IMG]  I use an AMNPS inside both my MES 40's and get 1/4 the output of smoke in that last picture and the Pimaster's Choice is up front. I have had the same setup since 2011 and was BANNED from using Hickory Pellets by...[​IMG]...Way too strong, for Her that is. [​IMG]  What flavor Pellet are you using? That really is more than enough smoke to get the job done...JJ
  3. Nope, I don't have a preference for heavy smoke flavor...I'm just not getting very much smoke flavor with the AMNPS! The first few runs I've used Todd's applewood pellets.Over the weekend, I went with a 50/50 split of applewood and Pitmaster's Choice (lit from both ends). I guess the one thing left to try is 100% Pitmaster's Choice (when I ordered the 2nd AMNPS tray, I ordered 20lbs of Pitmaster's Choice to go with the 20lbs of applewood I already have).

    I feel like there's a huge difference between a MES and the MB gasser. On a MES, there's little chance of your heat source "eating" up the wood smoke. For my propane smoker, this is really what I feel is the source of all my problems.
  4. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    There is a difference and it is totally reasonable that the gasser eats smoke. Apple is among the most mild flavored smoke woods we use. The PM pellets are much stronger. There are a lot of members that use your's and other model Propane Smoker's, both with the Mailbox Mod and Todd's AMNTS Tube. This is just the first thread I have seen of this nature. Just judging from that last pic, it is surprising that there is such a mild flavor on the meat...[​IMG]...I hope all works out...JJ
  5. rons

    rons Smoking Fanatic

    That is cool looking, it looks like the big smoker is an alien robot sucking the life out of the little guy lol

    Seriously, very cool. and you have a 'smoke stack' on your smoker too, that's also really cool.

    I've had good luck using a cast iron smoker box balanced way off on the chip tray deal with pellets in it. Sometimes I use my amazen smoken tube in there, that took some trial arrangements to have that smoke, not catch on fire, or not go out.
  6. I went outside the other day and fired up the smoker (without food) and AMNPS tray to see if I could think of more solutions to the problem. Before I even plumbed the wood smoke from the AMNPS tray, my cook chamber was pouring smoke out of the stack and back vent. And it dawned on me...the reason that last picture has so much "thin blue smoke" coming out of it is because my fat drippings are being burnt off. When I was cooking spareribs this past weekend, I didn't have a water pan or drip tray under the ribs. The fat from the ribs was dripping right onto my hacked up stainless steel baking sheet that's acting as my propane burner baffle. Fat + close proximity to heat = tons of sustained smoke.

    The 2nd AMNPS tray arrived today, and I've thought of another mod to make to try and direct the wood smoke from the AMNPS up  into the cook chamber and away from the burner. Once that's done, I'll take some pictures of the interior of my smoker so you guys can see all the MacGyver crap going on in there...even if it works or not.
  7. Thanks! Right now it might be cool looking, but it's absolutely frustrating to figure it out. Nothing worse than running a smoker for hours and hours, and then you taste the final result and there's hardly a difference between smoking and cooking in a oven.

    Part of the reason I went with the A-Maze-N tray was because I liked the idea of having 8-9+ hours of smoke between wood refills. That would make long cooks for things like brisket a whole lot more manageable because when I run off large wood chunks, that only lasts anywhere from 1-1.5 hours before more wood needs to be tossed in.
  8. tropics

    tropics Smoking Guru SMF Premier Member ★ Lifetime Premier ★

    Have you been letting the meat dry to form a tacky surface?  
  9. cmayna

    cmayna Master of the Pit OTBS Member SMF Premier Member

    I was wondering the same.   I also agree with Jimmy J  that the last pic sure shows plenty of TBS coming out the stack and back vents.
  10. rons

    rons Smoking Fanatic

    Question, why can't a person run the smoker tray inside the smoker? I run my Amazen Tube inside. I had to play with it's setup, but it works actually too good in there. I end up usually with over smoke flavor. This weekend I did some jerky and it was a bit too smokey and was actually thinking next time, I'd only fill the tube 1/2 way for 2-3 hours of smoke, then let it finish smokeless after that.

    When I first got the smoker, I set the tube above the water pan (used water as I was smoking a beef roast). It kept going out from the water steam. So I switched places, put the tube below, water above. Then it caught on fire, had a giant Olympic Mesquite Torch lol. Then I found if I put the factory water pan in as directed but no water, just use it for a shield, set the smoking tube on that. Then if I wanted water for that particular smoke, put a big cake pan as a water pan on the bottom rack above the tube, it would smoke perfectly. For the jerky I just skipped the top water pan but had the tube above the empty factory water pan. The tube kept smoking perfect for 4.5 hours but wow, too much smokey flavor!
  11. cmayna

    cmayna Master of the Pit OTBS Member SMF Premier Member


    So you now have to AMNTS laying inside the stock water pan?  What if you are smoking pork or other possible fatty meats that drip?  Has the dripping fats caused an issue for the tube?
  12. rons

    rons Smoking Fanatic

    I set it like this, this way the tube runs perfect for 4-5 hours and I honestly myself, sometimes get too much smokey flavor, and I like smokey flavor!

    The upper cake pan not only catches drippings, or is a water pan, but also keeps the tube from beaming a direct line of smoke on the food.Without that, the tube sometimes will put a narrow stream of smoke and one of the meat pieces or part of a larger roast, will have a big smoke dot on the bottom, not tasty!

    Last edited: Jul 23, 2015
  13. rons

    rons Smoking Fanatic

    I used the above method to make the best jerky I've ever had, but used charcoal kinda minion method to keep around 170 average temps.

    Tritip roast, cut with the grain, cured and just seasoned, no marination or sugars.


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