First run on new reverse flow

Discussion in 'Reverse Flow' started by hickorybutt, Jan 5, 2014.

  1. hickorybutt

    hickorybutt Smoking Fanatic

    I joined SMF yesterday (and did Roll Call).  I just bought a new reverse flow last week for a guy who builds custom smokers.  Paid $600 (which is cheaper than most brand names) for a 1/4" steel offset barrel with reverse flow plates.  I'm happy to report that I maintained temps across the entire cooking chamber within 5 degrees.  Since the steel is so thick, it took a LONG time to get up to temp, but boy once it got there it was there to stay.  I upgraded from a CharBroil American Gourmet.  So this is a big step up.  I gave it an opening run yesterday with lamb shanks and chicken.

    Meat just put in:

    Since I am still learning on this smoker, I built a charcoal basket and tried to do a 'U' pattern for a long burn time.  I couldn't really get the smoker past 200 degrees with regular briquettes in a charcoal basket.  Granted I was fighting 20mph winds and 30 degree weather.

    So after an hour of fighting low temps, I went to straight firewood sticks (mix of oak and hickory) and the thing held 240 degrees like a champ.  Nothing more beautiful than blue smoke spilling out the chimney exhaust.

    Here is a picture of the cooked meat ready to come out.  4 hour smoke.  Lamb shanks were bare in smoker for 3 hours, and the 4th hour in a pan with red wine sauce.

    Dinner is served.  Chicken was pulled and frozen.

  2. buda q

    buda q Smoke Blower

    Welcome! That's a nice looking rig, and good looking Q as well!
  3. radioguy

    radioguy Smoking Fanatic


    Welcome to SMF. This is the place to read and get answers. You may want to try lump charcoal... Burns really hot compared to briquettes. Start a small notebook to annotate your cooks. Times temps weather and so on. It'll become a good reference.

  4. hickorybutt

    hickorybutt Smoking Fanatic

    Thanks for the suggestion. I considered using lump, but had a bunch of Kingsford from the July 4 sale. I'll likely try to start a base with lump next time and then just keep adding sticks.
    Last edited: Jan 5, 2014
  5. buda q

    buda q Smoke Blower

    I use briquettes on the bottom, pile on split wood, then torch it up with a propane torch to start it. I only use wood after that. Don't use lighter fluid if you can help it.

  6. alaska

    alaska Meat Mopper

    Nice very nice....
  7. abaralnek

    abaralnek Fire Starter

    nice looking pit!! i have to ass though that it looks like the stack is smaller than what would be needed?
  8. hickorybutt

    hickorybutt Smoking Fanatic

    The stack is the same size as what was on my CharBroil. And the cooking chamber is the same size too. So proportion-wise they are the same. I know a CharBroil isn't a good measuring stick, but they are a common brand.

    When could this be an issue if the stack isn't big enough? I'm asking because I'm not that knowledgable on it. I was able to get good airflow and maintain temps when I got there.

  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    If you FB gets too hot, say 100 deg. hotter than the CC (or something like that), there may not be enough draft to suck the heat out..... Or your FB could use another inlet across from the FB/CC opening to help move the heat into the CC... Or you could make the stack taller to add more suck....

    Last edited: Jan 7, 2014
    hickorybutt likes this.
  10. Congrats on the new smoker, for peace of mind you can check your stack size using the Feldon's Pit Calculator. Now in saying that when you put in your CC size you may have to play with the FB size to get it to come out at 100% even though your fire box may be larger, this should give you opening sizes and stack height to check yours against. That way you can see pretty quick if you need more stack, additional openings in FB etc. I know Dave O has helped to many people to count with their pit calculations.

    hickorybutt likes this.
  11. hickorybutt

    hickorybutt Smoking Fanatic

    Thanks guys.  I'll look into all of this in a couple of days and see where it nets out.
  12. I have smoked on several kinds of smokers in my 30+ years but I don't think I have liked any of the smokers better than I do my RF. You will have many years of fun and enjoyment ahead. Again this is a great forum and super nice folks.

  13. hickorybutt

    hickorybutt Smoking Fanatic

    Thanks Gary.  So I am going to plug my smoker dimensions into the Calculator probably this weekend.  I get home from work after dark every day and won't have a chance to measure and take any good pictures until Saturday.

    One quick question, and this would be for both yourself and Dave.  I saw in other forums where you guys were talking about the opening between FB and CC.  The picture below is of my opening that I took a few days ago.  It has a damper, and I currently have the damper at 45 degrees.  The builder said to set it there.  During my smoke on Saturday, I played around with the damper when the temps were having trouble climbing.  When I opened it all the way, rather than raising temps it just moved temps all to one side (on the far end of the CC) because of the RF plate.  When I moved the damper up, I think it just closed off the small opening on the RF plate firebox side and pushed heat to the opposite side.  When the damper was at 45 degrees it evened temps across the cooking chamber.

    Do you guys think that the damper is restricting total heat flow and impacting temps?  I'll measure the opening size, damper, smoke stack, etc. this Saturday to get a more accurate assessment of everything.  Thanks!

  14. radioguy

    radioguy Smoking Fanatic

    I'd remove that FB/CC damper, there is no need for it if you have properly sized air intakes\ openings on your FB.  Take your measurements and put them up here...someone will help you out.  Take some pictures of your air intakes and measure those as well.  You should have intakes at  or near the fire grate level and one located higher up on the FB.  

    Once dialed in you will be able to control your temps much better.

  15. I do not have a damper on mine FB to CC.  If you are getting a lot more heat on the opposite end of where your FB is, you may have a smoke stack issue. Once you check the calculations this weekend you will know. The opening size from the FB to the CC is important will be interesting to see how it calculates. And as Dave points out a lot of the time you may simply need a little more air flow in your FB door.

  16. After looking at your smoker picture again, I suspect the stack may be a little short. You will know this weekend when you do your calculations. If that is the case, easy fix.

  17. buda q

    buda q Smoke Blower

    I agree. And I think that Dave O will tell us that the 90 degree bend on the stack is a significant choke/friction point.
  18. hickorybutt

    hickorybutt Smoking Fanatic

    I was able to get a few pictures and measurements today and plugged them into the Feldon calculator.  As it appears, my stack is in fact too small. 

    Cooking Chamber:  36" x 20"

    Firebox: 20" x 20" x 20"

    Stack: 3" diameter x 11" height.  (The Feldon calculator suggests 56" height if the diameter is only 3")

    Opening from firebox to CC (half oval opening): 16" x 4" at middle point.  I estimated a total of around 40-45 square inches for the opening.  Feldon suggests 64 square inches at my current FB, CC, and stack dimensions.

    Opening on RF plate:  3.5" on side opposite FB.  0.5" on FB side.  It is an adjustable plate with a 4.0" gap.  Where it is currently set gave me an even temp.

    Didn't get a measurement on the FB inlet, but they appear plenty big.  The inlet is right at grate level.  No opening above or below.  Picture is below.

    What do you guys think?  Is my issue primarily the smoke stack?  Would taking the damper off the CC to FB opening help?  Would that affect the RF heat distribution at all?  I'm not equipped to add a new smoke stack, I don't have any metal working experience and don't really have tools to cut a new opening, patch existing opening, etc.

    I think one of my biggest issues on Saturday was that I didn't start with enough fuel.  I only added 80% of a charcoal chimney of briquettes to my basket, hoping for a long burn time by adding more unlit coals.  That didn't do the job to get up to temp.  Once I put a 12-15" log in there on top of the coals, it got up to 240 degrees no problem and one log would hold temp for about an hour or so.

    This is the FB-to-CC opening, damper fully open.  The angle is kind of bad, but the length is 16" and the height at the middle point is 4".  I estimate 40-45 square inches.

    Firebox inlet, fully open.  Right at grate level.  The FB is 20"x20"x20"

  19. hickorybutt

    hickorybutt Smoking Fanatic

    Also, the Feldon calculator says that my FB is twice as big as what is recommended.
  20. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    hickory, afternoon..... FB size is fine.... actually better for long smokes... Can you remove the damper in the FB/CC opening... that should make the FB/CC opening larger... 4" x 16" is about 44 sq in... 5" x 16" would be about 62 sq in... close to just right.. I would lengthen the stack to 30"... use a piece of 3" truck exhaust pipe... 30" x 3" ID is what MY calculator calls for in a 36 x 20 smoker CC.....

    Feldon's calculator has some inherent problems...

    hickorybutt and malin like this.

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