gasser mod for AMNPS......

Discussion in 'Propane Smokers' started by chefrob, May 4, 2012.

  1. chefrob

    chefrob Master of the Pit OTBS Member

    az
    there seems to be a lot of questions about mods for a gasser using the AMNPS for smoke durring a hot smoke. i normally don't use one for a hot smoke in my gasser but that is mostly since the flame eats up all the oxygen and doesn't let the AMNPS do it's killer job like when cold smoking in a gasser.

    after seeing pops mail box idea:

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    and NWDave's SFB mod:

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    these 2 great ideas got me to thinkin' 'bout the best way is to some how get the AMNPS out side the smoke chamber where there is more oxygen to feed the AMNPS so it can do just as good hot smoking as it does cold smoking in a gasser unit. i am looking for a CHEAP way to do this with as little metal fab as possible so that others like me who don't have mad skills like some here do and still keep it affordable too. i will post my failures as well as what works in an effort to help all who can use it. i am also open to any ideas but don't get bent if i don't use them. i really like dave's solution but it is a bit bulky and i don't have a lot of room and it ain't CHEAP like me. as for POP's solution the same thing since his is mounted from the back of the mail box to the smoker and sometmes i use 2 AMNPS at the same time. remember these mods are for MY smoker and may or may not work on yours......my goal here is to maybe give you some ideas like Pop's and Dave gave me....hell, i still might end up using one of their ides when all is said and done.

    well here is the first stage where i was just thinking to get the AMNPS's outside the smoker, my idea was to use 2 L brackets for shelves @ around $1.50 each / 2 per side:

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    so that part was easy and only cost a little over $5 and can be reversed if it don't work.
     
  2. chefrob

    chefrob Master of the Pit OTBS Member

    az
    the next step is to figure out a way to get the smoke into the chamber. i searched all over  home depot in the roofing andheating and coolong/duct work areas and came up empty handed. at this point i did not want to buy some flashing and build 2 vents since a roll of flashing ain't as cheap as me and i didn't want to try my hand a metal fab just yet. i did see one of those orange buckets and came up with an idea that was a fail but does have potential so here it is:

    i had smaller buckets from work and thought this might work so i figgured what the hell:

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    i figured this was not a bad idea since almost any one could get a plastic bucket for CHEAP and cut it i 1/2 and zip t with a couple of screws and have a pretty good seal. after testing this out the biggest problem i saw with this is the fact that the buckets are plastic and it did heat up with the propane on after only 10 min. another thing is this bucket has too small of a radius. i did drape some sheets of foil over it to go past the bottom of the AMNPS and then smoke did go into the smoker at a pretty good rate, however some did manage to blow out from the bucket when a breeze came by. in my book this is a fail but it brought out airflow dynamics with the flame on and practical challenges like wind and such to consider.
     
  3. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

  4. nwdave

    nwdave Master of the Pit SMF Premier Member

    NOW, there's a thought.  Vent Duct Pipe.  Galvinized though.  Makes me wonder at what temperature point does heat generate a fume reaction?  Does the AMNPS generate enough heat, when smoldering (the point at which we get the smoke) to cause this fume reaction.  I bring this point up because of our almost paranoid reaction to the introduction of anything related to the construction of a smoker that involves a part that is galvinized.  I know I certainly don't have the knowledge skills to know this piece of information so consequently I pretty much discard anything galvinized out of hand.  The Vent Duct Pipe could be perfectly safe, I just don't know for sure.

    I'm with you chefrob on experimenting and adapting to make something work.  Many times it's a unique adaptation that may or may not work with someone elses smoker.  Plus, when you bring into the "project" your own skills in fabbing something, your fabbing approach will be different, perhaps.  I don't have any welding skills for example, so the way you look at construction would naturally be different. 
     
  5. dutch

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

    Dave, I've read on some welding forum that zinc begins to burn at 785°. I think that the dryer vent would be ok to use since it wouldn't be making direct contact with the AMNPS-but then YMMV!
     
  6. chefrob

    chefrob Master of the Pit OTBS Member

    az
    JJ, i was looking at those but they are just not big enough.

    i wondered about the zinc issue since most ductwork is galvanized......i think the majority of the heat was coming from the burner itself but i don't see it getting much over 200-400 deg. maybe i'll run it on high for 30 min to see what temp i can pull off of it.
     
  7. chef jimmyj

    chef jimmyj Smoking Guru Staff Member Moderator Group Lead OTBS Member

    I just thought I'd throw it out there. I can't imagine much of an issue since it is duct pipe and if you ever put your hand against the trunk line coming off a Gas fired forced hot air furnace it has to be hotter than what an AMNPS will generate. But, Food I know, Zinc...Not so much...JJ
     
    Last edited: May 4, 2012
  8. donr

    donr Smoking Fanatic

    How much air will enter the smoker from underneath the burner from the bottom?  If this area pulls in a lot of air, just attach two rails to the underside so you can slide the Amnps underneath.  If wind is a consideration, like on my Inlaw's Charbroil model, make a skirt that attaches to the sides of the smoker box that will help close the gap to the ground.  This would help direct more smoke upwards & also stop the flame from being blown out by a wind gust.

    You could test this by setting the AMNPS on a couple of bricks under the smoker.

    Can you cut a hole out of the back of Pop's mailbox & screw it to the side of the smoker like you have with the bucket.  You could remount the air meter from the side of the smoker to the bottom of the mail box, so you don't have to smoke with the door open, and rivet on a small stack to help with wind gusts.

    Just a few ideas.

    Don
     
  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    [​IMG]........   I'm in ...... 
     
  10. s2k9k

    s2k9k AMNPS Test Group

    I'm working on something similar to the mailbox idea, I started another thread about it and will post more as it progresses. I have gained some ideas from this thread and others on here. Thanks everyone for all the input for making this work!
     
  11. chefrob

    chefrob Master of the Pit OTBS Member

    az
    don, some good ideas.......never thought about under the smoker. after cruzin' the isle of home depot i pretty much have 3 ideas.....

    pops mailbox - i like this one since it protects the AMNPS from the wind and funnels amost al the smoke into the chamber cost $12 for the mail box and $5 for the flange

    fabricated metal hood - this is the sleekest but most difficult to get it right....i made a pattern out of cardboard but need to get some metal  and some sort of gasket- cost $15-$30

    duct work - not bad but pretty damn bulky and it ain't cheap

    will work on it this week
     
  12. jrod62

    jrod62 Smoking Guru Group Lead OTBS Member

    I was thinking about how to hook up the AMNPS to the outside
    of my UDS. was thinking about making metal box but a mailbox
    would work and wont have to build it. Having a pipe between the mailbox
    and my UDS and the shutoff valve on the other side of the mailbox ? Might work.
    Will just have to try and see.
     
    Last edited: May 8, 2012
  13. nwdave

    nwdave Master of the Pit SMF Premier Member

    Like DaveOmak, I'm in too.  What can be done with a UDS should be able to be adapted to a WSM.  I discovered in my tests with the AMNPS and a GOSM that you must have a reasonable draft from air intake, across the AMNPS and then into the chamber.  We also discovered that heat in the main chamber "devoured" to a great extent, the viewable smoke.  BUT, the smoking of the meat still occurred.  Eric, forluvofsmoke, and Todd know the science behind this, I must claim STML.  The other indicator, the smell of the smoke from the pellets was also present, as you'd expect if you were pursuing the tbs. 

    S2K9K also has a good thought process going with the tool box idea and this also bears consideration because I like the idea of being able to open the top lid and placing the AMNPS inside then closing and hopefully having a tight enough seal, to not loose smoke around the edges.

    ~Dave
     
  14. s2k9k

    s2k9k AMNPS Test Group

    Last edited: May 8, 2012
  15. I went with your idea and tested from underneath the burner on my Master Forge.

    I originally raised the AMNPS to get it as close to the bottom as possible, but didn't like it being so close to LP hose, and ignition wire. So..... I headed to Home Depot and picked up some galvanized aluminum step flashing to create a skirt on three sides.  

    The results were great and it's a super cheap mod!  Under $3 for five pieces of flashing.

    Link to flashing:

    http://www.homedepot.com/Building-M...0053&langId=-1&keyword=aluminum&storeId=10051

    My plan is to attach the flashing to the bottom of the smoker, which will create a shelf to slide the AMNPS into. Cover the rear air intake holes (if that is what they are?) with additional flashing and paint it all black with grill paint.  

    This was just a test, but I provided pictures below......... 

    View from the front:

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    View from the side:

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    Front view with the smoker tilted back:

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    View from the inside (camera doesn't show it, but the flame was on and there was lots of smoke coming up from the bottom):

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  16. tjohnson

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

    WOW!!!

    I Mean FREAKING WOW!!!

    How simple can this get!!!

    All great ideas, and incredible simple to make

    Todd
     
  17. nwdave

    nwdave Master of the Pit SMF Premier Member

    Gotta agree 110%.  Definitely an answer to using the AMNPS  with the Master Forge and other small footprint gassers.  Now you got me thinking about adding one to my GOSM to see how it works.  In fact, I know where two Master Forge's are that need this mod.  In your attachment, is the only air to the AMNPS coming in from the front?  How well does it work in the long haul, like a really long smoke?  Your picture shows just a small handful of smoldering pellets.  Do you get enough oxygen to take the pellet burn around the corners of the row troughs?
     
  18. Air to the AMNPS did not seem to be an issue.  The pellets in my test lasted about 1.5 hours.  The smoker has air intake holes (for the burner?) on each side and the rear (side picture shows the holes), which are about four inches above the AMNPS.  I needed to cover up the back holes, because a lot of smoke was escaping. 

    My next test will be attaching the flashing to the smoker.  I also plan on covering up the the holes mentioned above and drill 1/4 holes, in the base of the flashing, every half inch on all three sides. This should allow for plenty of oxygen to enter .  My only concerns is the smoke moving up through the burner.  Can the smoke in any way damage the burner? 

    Here's a quick drawing of what i'm thinking of doing.

    (Left side view of flashing shelf, attached below the burner of the smoker)

    [​IMG]
     
  19. tjohnson

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

    I don't think the smoke will hurt the burner, but the flame may burn up some of the smoke during combustion

    TJ
     
  20. Another update ........

    Should I be starting a new thread for this project?

    Anyway,  I built the shelf to mount under the smoker.  Total cost was $4.13.  The whole thing took about 30 min to put together.  It's probably a good idea to use work gloves, as there's lots of sharp edges, but very easy to construct.  It will be mounted to the bottom of the burner area and tested this weekend. 

    Any suggestions or ideas, to help me along, would be great!

    Parts List:
    • Aluminum step flashing - 4 @ $.54 each = $2.16
             http://www.homedepot.com/h_d1/N-25e...Id=-1&keyword=aluminum+flashing&storeId=10051
    • Aluminum window cap - 1 @ $.99 = $.99
             http://www.homedepot.com/Building-M...splay?catalogId=10053&langId=-1&storeId=10051
    • bag of sheet metal screws (8 ct) - 1 @ $.98 = $.98
             http://www.lowes.com/pd_57686-37672...screws&page=1&Ns=p_product_price|0&facetInfo=

    Total = $4.13 +tx

    Pictures:

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