Smoker/Pit rebuild

admin

Ok. So customer of mine has this pit They bought it from somewhere around Dallas I believe Anyway. The thing burn super hot and uncontrollable. I believe the issue to be the fire box design just doesn't make much sense. The fire box is 24" diameter by 24" long and leaks everywhere. Which is why I believe it is burning so hot. I plan to build a little larger fire box with bigger opening at the back of the pit. When I open the back if the pit we are going to install a baffle plate to spread the heat out and all the vents, doors and openings will be sealed with the Kevlar seals. So what would you all say is the biggest flaw seen in the pictures. Also do you believe that a valve is needed on the exhaust of the pit or is there a ratio I should be looking to achieve for inlet and exhaust volumes? All your help is greatly appreciated as usual!  Sent from my iPhone using Tapatalk
Reply:Being able to control exhaust is crucial to maintaining pit temperature.
Reply:I would look into adding dampers for the air intake and exhaust. This would give more control over the heat of the fire You have the option then of having the outlet partly or fully open/closed, same with the intakes. Maybe make the intake control operable from inside the trailer, so as not to have to go outside to adjust it. A rod extended into the interior could be used to do this. Also, if it were mine, I would have some sort of cover over the stacks to keep out rain water when not in use.What does it look like from the inside? How many racks are in it? Is there any provisions for making the cooking chamber lid easy to open?
Reply:The lid has a counter weight and opens very easily. The interior has one rack on about the middle of the vessel.  The. Another removable rack atop that which is about 24"x18" The middle rack is getting removed and replaced with a sectional one this will also allow me access to install a water boxThen the top rack is going to get bigger I didn't think that exhaust dampers where that crucial to pit temps I was going under the assumption of your only getting out what you are putting in through the fire box. So I suppose I need to come up with a damper that will work with the stacks still being in place. The stacks are getting changed over to bull hauler style that should keep a majority of the rain out. Do you guys think this fire box should be replaced or should we try dampers at the exhaust first? Sent from my iPhone using Tapatalk
Reply:joe,If it were me I think I'd start with getting some good dampers on the exhaust stacks.   I think you'll be surprised at just how much that will help regulate that pit temperature.   After that I think the next best thing you could do to improve on it is put in that baffle plate in to spread the heat that you mentioned.
Reply:Thanks guys that's where I will start then. Exhaust and then baffle thank youSent from my iPhone using Tapatalk
Reply:Definitely control the exhaust and the intake. on my smoker I control the intake into the fire box, the exhaust/intake from the fire box to the cooking chamber, and the exhaust stacks out of the cooking chamber. If you block smoke from leaving, you can't bring in the air to make the fire hot. that's why many smokers use exhaust dampers over intake dampers. the dampers between the fire box and the cook box are used to regulate and direct heat to help balance the temp in the cook box. heat baffles in the cook box over the exhaust help with this as well. and finally, the control of the intake of the heat box is how you increase and decrease the heat of the fire. and the amount of smoke the fire puts off.go on to "www.thesmokering.com" to get a better idea of the ratios for fire box to cook box and for intake/exhaust sizes.There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:Does the tubes from the fire box extend into the cook chamber, or are they flush with the inside? They look to be 4"x4". On mine I added a piece of 4x4 tubing from the firebox all the way across the cook chamber, with holes on both front and back to distribute heat evenly across the whole cooking area. My air intake and exhaust is also 4"x4" tubing. On top of that I made angle iron racks to hold two water pans. With you having the three tubes, you will need a larger tube to serve this purpose, maybe like 10"x10". Doing this will act as the baffle mentioned above, and serve to hold the water pans on top of it. Make the pans removable so they can be taken out for cleaning or replacement, or left out if not needed/wanted for the cooking at hand.I made the dampers for the intake and exhaust like butterfly valves, and they close off pretty tight when shut. I have had times when I had a good fire still going when the cooking was done and shut off both inlet and outlet, and it choked down the fire to where there was still usable wood left in the firebox after the fire went out. For you to add dampers like this to this pit, you could drill a hole all the way through the stack the size of the shaft you want to use. Then cut the stack off at the holes, install the damper, and weld the stack back on. That way you can put them where you need them for easy adjustment, instead of just where you can get to them NOW for easy installation.This pit appears to be built on a livestock trailer. What do they do, haul the cows/hogs in on the hoof in the front, and butcher them on site for the cook out? Can't get the meat any fresher than that if they do.Last edited by Bistineau; 08-26-2014 at 06:18 PM.
Reply:One question on the fire box are the tubes open direct to the cooker or is there a baffle in the top of the fire box. It looks like you could have flames going up the tubes into the cooker the way it is .just wondering.gxbxc
Reply:as a pit builder and smoker - everyone above is pointing you in correct direction. exhaust damper is ABSOLUTELY NECESSARY. also, an air input vent on the firebox will be required. these two items alone will allow for heat/temp control.you've got the right idea putting a baffle plate into the cook chamber as well, that will diffuse the heat a bit, make it more of an indirect heat, use 1/4" plate for that. then you have the option of using the water pans or not, which if you know what your doing, the water is irrelevant in smoking. the reason you have water in a 'vertical water smoker' is because the construction of those is with very thin metal, which does not retain heat. the water acts as the constant of the heat, where it both dampens the heat spikes off the fire, and also retains some of the heat from the times the fire gets a bit low. in a big heavy duty smoker like this, the construction material of it (along with the 1/4" baffle plate) will help retain the heat throughout the entire unit for more predictable and constant temps.1) exhaust vent2) firebox intake vent3) baffle plateand 4) seal up the leaks
Reply:Any pictures of the inside of the trailer?  Was this a competition cooker or ????
Reply:Bistineau- I love you butterfly damper idea. That will actually save me a spot of work. Gxbxc- and all others that asked. The heat risers die right inside the cook chamber no baffles of any sort. In fact right now they are not even fully welded. Kuzoneddie- not a comp cooker yet. But that's what they are looking for which Is why I am seeking guidance as I am no smoker guru myself. We are starting today with the cutting and material listing I'll let you all know how it goes. Thanks for the input!Sent from my iPhone using Tapatalk
Reply:Would you like to see the dampers that I made in my smoker?
Reply:Hell yes I wouldSent from my iPhone using Tapatalk
Reply:I build mine like this. A damper in the middle is a must. Attached ImagesLast edited by lugweld; 08-28-2014 at 10:55 PM.Esab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:Here's some more of the damper valve in construction.  Above you can see that I welded two pieces of flat stock on either side of the butterfly to give it a tight seal.  It does not significantly impede the flow of heat.  In one of the above you can see the heat plate being constructed.  The heat plate need not come out more than half way to adequately spread the heat and smoke.  I actually created baffles inside the heat plate to spread it evenly. It worked. Attached ImagesEsab Migmaster 250Lincoln SA 200Lincoln Ranger 8Smith Oxy Fuel setupEverlast PowerPlasma 80Everlast Power iMIG 160Everlast Power iMIG 205 Everlast Power iMIG 140EEverlast PowerARC 300Everlast PowerARC 140STEverlast PowerTIG 255EXT
Reply:I like that idea lugweld. I'll likely incorporate a baffle like that in this smoker.  Here is the progress as of yesterday. We had a long Labor Day weekend so not much prior too. The pit is outThis is a shot inside the pit. Not much to see there yetHere is the back I had to remove the fire vice to get the pit out. After our changes the pit will be powder coated and reinstalled. So the fire box is going to get closer to the cook box so the whole thing can come out as a unit. Reasoning for that is we are going to build a bigger badder pit for competitions as soon as this one is up and running. Removed the rear bumper from the trailer as it was pretty terrible. Along with the silly heart panels that were on the back. They will be getting replaced with some custom cut DP aluminumSo it's not much but it's a start Sent from my iPhone using Tapatalk
Reply:I'll attempt to avoid speaking engineer in this answer, but the ability to control inlet and outlet flow area is critical to temperature management. Hot coals generate substantial radiation, and in humid air cause mighty natural convection currents. If the exhaust is wide open those currents will accelerate air out very quickly, and that action will draw air in as fast as needed to not break physics. That generally forms a positive feedback loop in the presence of burning coal and temps climb until the coals can't put out any more energy. Now your brisket is ruined.The automated smoker/grill I designed relies on regulation of inlet opening but will only work if I set the exhaust restriction correctly for my desired temperature range. One day I'll add a control for the exhaust position as well, but for now I'm happy with the system response as it is.Tweco Fabricator 211i
Reply:I have to say I don't have anything to really add, but I do have a question. I have never seen a mobile smoker, why the need for mobility? I always just see stationary ones.
Reply:Competition brisket and ribs is the cause for mobility. Ajmartinez thank you sir for the explanation makes perfect sense as to why the temps are too hot on the grill. Sent from my iPhone using Tapatalk
Reply:Originally Posted by BistineauWould you like to see the dampers that I made in my smoker?
Reply:Originally Posted by Jeff000 I have never seen a mobile smoker, why the need for mobility?
Reply:Originally Posted by drillerjoeCompetition brisket and ribs is the cause for mobility. Ajmartinez thank you sir for the explanation makes perfect sense as to why the temps are too hot on the grill. Sent from my iPhone using Tapatalk
Reply:Originally Posted by Jeff000I have to say I don't have anything to really add, but I do have a question. I have never seen a mobile smoker, why the need for mobility? I always just see stationary ones.
Reply:Originally Posted by ajmartinezNo problem at all man. I wanted to design an automated brewery but my capstone prof said no. He approved the pit idea though and my senior year I learned way more about fluid mechanics, heat transfer, and control systems than I even knew existed. If you have any questions about the science of a BBQ pit just give me a shout!Originally Posted by lugweldScience of Barbecue pits?  It's more of an art form.  You can make good barbecue pit with a piece of grating, a few concrete blocks stacked up and old piece of tin.  If you don't know that or forget that, then you dont' know Que.
Reply:Originally Posted by ajmartinezThere is no "more of" as the two are inseparably linked. You can do a whole lot amazing BBQ without understanding an ounce of the science behind it. I just offered to explain the science if he cared to know it.
Reply:Some nice grills here guys! Got me looking for a propane tank !
Reply:Tackit that Brazilian pit is an awesome idea.  Thanks for sharing! Ok so we have some progress on the pit project. Yay! First off I removed the riser system and put the fire box right on the the cook chamber and opened the port for the heat to flow directly in through a 4" x 22" hole. Inside the cook chamber I added a baffle that forces the heat to the bottom center of the cook chamber. Then I installed a rail system inside the cook chamber to set the tuning plates on. I made the tuning plates out of 0.25 plate with a 4-1/4" hole in the center with a piece of 3/4" cold roll for a handle welded on the back. I have a few pics of the progress and will get some better ones tomorrow. Loving this project, and! I got an offer with investment to start building competition pit trailers full time. Sent from my iPhone using Tapatalk
Reply:Okay so I got the baffles installed or dampers for the exhaust keep in mind this is ruffed up we're going to burn on the pit tonight and see if we can control the heat like we wantDamper closedDamper openSent from my iPhone using Tapatalk
Reply:Coming along real nice Joe. How ya going to deal with the air intake for the firebox?
Reply:There is a vent there. We are burning the pit now. Sent from my iPhone using Tapatalk
Reply:So end result is the fire box needs better venting for certain. I am actually going to revamp the door on the fire box and give it a better seal and more effective ventilation. The pit was easy to tender. The dampers in the exhaust worked wonders for the temperature control. You can actually sent the exhaust and just keep the fire stoked and fed and it will easily maintain temperature Thanks for the help on that guys! They still want a water box in the pit I'll be tackling that next. Here is a peek inside The plates worked perfectly. You can see on the back side where the grill was previously. I am going to move it down just an inch or two to make a bit more room for a top rack as well. Sent from my iPhone using Tapatalk
Reply:Looking good!Tweco Fabricator 211i
Reply:Thanks AJ it's been a fun project thus far. Sent from my iPhone using Tapatalk
Reply:Originally Posted by drillerjoeThanks AJ it's been a fun project thus far. Sent from my iPhone using Tapatalk
Reply:No it is on going just been on hold I'll actually be working more on it this weekend after I do the frame fix on my truck. Sent from my iPhone using Tapatalk
Reply:Here's a little update. Floor is going in the trailer and building the wings for the rear sides now as well. Sent from my iPhone using Tapatalk
Reply:Sent from my iPhone using Tapatalk
Reply:Tail light assembly built and installedSent from my iPhone using Tapatalk
Reply:What happened here and how do I get rid of the stain on this aluminum? Never seen this before. Sent from my iPhone using Tapatalk