I'll try to answer a few of your questions for you. Your counter weight will be determined by the size of your door and the angle you want it to open, so you'll have to figure that out when you get to that point. I would think that you'd want two doors on a rig this size but I'm not sure what you plan on cooking on it. I would install the baffle plate level and tilt my trailer. Try not to recess the FB into the CC anymore than you have to, this will help avoid a hot spot on that end. The BP is normally an extension of the top of your FB, some guys raise the BP an inch higher than the FB. The BP opening on my pit is the same as the throat from the CC to the FB, some are built to be adjustable and then tuned to your liking. There are a lot of pits on here that are similar to what you're wanting to build so I would suggest looking through here and getting some ideas. Once you come up with a rough sketch of what you're going to do just put a picture on here and the guys will help out when ever you need it. This is just my opinion and I'm sure others will come along and help you out better than what I can.
Hi and welcome. My own personal thoughts are that you have found the right place. You'll probably have all of your answers within a few days. I believe that your chimney stack thickness is fine. I am using similar 6" tubing but thanks to the encouragement of Gizmo, a founder here,I am using an elbow that allows the stack to be removed for transport. And guess what....if it totally disintegrates in a few years, it's a simple straight piece that is easily just cut and slipped on..and the measurement is the vertical portion only. So that's one point.
From what I have come to understand, Big T is correct... you are better off keeping the baffle plate level and adjusting your trailer tongue up or down for the angle.
Your firebox will be best made from 1/4" or better so your 2/5" is great. I did not use any support frame in my FB just edge to edge welding contact and it is coming out great. It is heavy however. As for your trailer weight, I am using a 3500# spring but my 275 tank and trailer only seem to weigh in around 950 lbs so far. It's not finished yet but would have never thought the weight would add up this high. It was the guidance I got right here that brought me to the bigger capacity and I am SO happy it worked out this way. I don't see your creating something with an additional 500 lbs, although possible. The folks here know what the plan should be and give the greatest advice so ask away
Make no mistake, there ain't no powder in this Puff ! And... I'm not really a crazy person but I play one in real life
First things first.
Hello and Welcome to the site - we're glad you brought your project here and I'm sure you will find the right advice to 'get 'er done'! … always nice to hear from across the pond.
I'm right-handed so I like the FB on the left end of the tank as you approach the CC door since there is always a table sitting at 90 degrees to the tank at the other end for holding meat, tools, etc. - make that decision now.
Pick a top-dead-centre on the tank (maybe opposite the hole you're patching to put it at the bottom?) then roll the tank on the ground against a piece of angle iron to act as a straightedge and mark the tank lengthwise at that point. (A sharpie works well)
Using a dressmaker's tape measure, determine the circumference and measure from this line 1/4 of the way around for your door height. I agree that 2 doors would certainly be easier to manage for nearly all cooks except whole hog. If it's 2 then leave a center post about 4 inches (10cm?) when you draw the doors on. Using this gauge steel I wouldn't worry about vertical support much if you go with a single door though.
2 ways to control the hot spot and you need to make that decision right now…..
1) cut into the tank end to allow your FB to mount INTO the tank volume and leave the top on the FB all the way to the throat opening and put the BP an inch above that. The top of the FB that's inside the CC will act as a 'shadow plate' forcing the radiant heat in the FB roof to re-radiate to the BP. ….. slightly warmer - yes ….. a true hot spot - not likely.
2) cut the end off the tank just inside the end bell seam. Cut a new flat end plate with the throat opening already removed (see Earl's build thread). Butt the FB throat opening against that opening. You just moved your hot spot outside the CC where it won't be a tribble at all (Star Trek reference) This method is obviously more expensive since you have to buy new end plate steel.
Either way - hang onto the drop offs because you can cut a piece from them to patch that hole you mentioned.
Stack opening is another early decision….
If you go the first method it's easier to just go out the top of the tank at the end so it will move your door opening back some from the FB end to allow room for the stack exit hole.
If you go the new end plate method then build a simple elbow (see Earl's build thread) and come out the new end plate. Advantages to this method are that your door can be larger (longer) and drippings from inside the stack (typically high creosote content) fall into this elbow and can't fall onto what you're cooking.
Talk to your helper and get his take on fabricating these methods - you'll find a good compromise and be moving forward in no time.
If you get frustrated repeat after me; "It's a HOBBY"…. remember that there are stiff penalties for not posting pics and having fun …. just sayin'
And on the eighth day God created barbecue …. because he DOES love us and he wants us to be happy.
Current smokers: Egor (trailered RF) and Easybake (tabletop pellet drive)
You have come to a good place for advice. It is good to look at several of the builds here and then use the designs that will work for you in your build.
Thanks for all the great advice, especially that tip for marking the door, never would've thought of that myself
My tank is actually 25.6" in diameter, probably a typo on my part previously. I checked the reverse flow plate by drawing it in Sketchup, the width seems to put it at the correct height. Here's a rough idea what I'm thinking.
As you can see, there's just barely space for a second rack.
What do you think about the rack spacing? I'm going to be mostly cooking pork necks (similar to butts but smaller), brisket packers and brisket flats. If I need to cook something taller, I'll just use the bottom rack and remove the upper one.
I'm going to cut into the tank and notch the FB. I may have a CNC controlled plasma at my disposal, so I'm thinking I'll cut the FB plates with it and make all the openings at the same time (half-moon, intakes, etc). And of course all the other parts I can
The hole I need to patch up is pretty huge, I would say it's at least 12-15" in diameter.
Just though of something, since I need to buy and modify an existing trailer, it's probably made out of galvanized steel. Could I burn off the galvanization from a few spots from the frame in well ventilated area wearing a half-mask respirator and then weld my smoker frame to these bare spots...?
The reason I need to buy an existing trailer is that it's very difficult to make a trailer road-legal here in Finland, it's much easier to buy one that already has all the required paperwork done and is approved for traffic.
Your sketch is almost identical to my 25'' smoker so I would say it will work just fine. I have used a grinder to remove the galvanized coating on a lot of boat trailers and weld mild steel beams in place so I don't think you'll have any problems with that.
What if you made 2 smaller cookers out of this 1 tank and sold one of them? Would that pay for the other one? Would it be a large enough cooker for your plans? Should I go back and sit down in the corner?
jm2cw
And on the eighth day God created barbecue …. because he DOES love us and he wants us to be happy.
Current smokers: Egor (trailered RF) and Easybake (tabletop pellet drive)
Is there any disadvantage to cutting my CC door bigger than 1/4 of the circumference? I'm thinking I want my first rack exactly at the center, so I'd either need to make my door bigger or make it further down than 3 o'clock position.
That would leave me around 3" to reverse flow plate, so that's probably ok.
Also, I just had an idea for the racks. I was going to buy a sheet of flat expanded, but it's a bit expensive here.
How 'bout if I use the CNC plasma to cut a lot of holes into 1/8" steel? I probably could even cut diamond pattern, if there's any advantage over round holes...
A lot of guys have gone an inch past noon and 3 o'clock just for rain run-off on top and to allow the bottom grate to be exactly at 3 o'clock.
If you're gonna use a CNC plasma to cut your grate out of sheet-metal at least cut out your initials or flame shapes instead of just diamonds …. just sayin'
And on the eighth day God created barbecue …. because he DOES love us and he wants us to be happy.
Current smokers: Egor (trailered RF) and Easybake (tabletop pellet drive)
Yeah that's true, I'm just concerned how a "wild" cut-out would affect cooking. Or am I fine just by cutting out something almost uniform with around 50% open area...? I guess it's not so important in indirect...
I marked my doors today, used existing welding seams on tank to measure straight lines, I think they are straight enough.
Also decided to go with two doors, fantasized a while about doing only one door, but realised it would be really impractical.
Am I fine with 102% firebox size if I want my smoker to run at 350 F sometimes...?
Still haven't made a single cut, I know I'm overanalyzing a bit, but...
What are the advantages of mounting my firebox lower and extending the baffle plate all the way to the end over the FB versus mounting my firebox higher and welding the baffle plate to my firebox?
I already decided to mount my firebox higher and weld my baffle plate to it, but then started thinking (too much) once again
And also, in what order should I proceed with the build? I'm thinking I should first patch the huge hole even before cutting doors, so that the heat from patching the hole won't warp anything...? Or could I cut the doors out first? Can't find a "hand-held" regular plasma anywhere, so I'll have to cut them out with angle grinder
I have seen some guys have an extreme hot spot when they tucked their FB too far into their CC. If I was going to tuck the FB into the CC I would do it a little lower and run my BP over the top of the FB and leave at least an inch of clearance between the FB and BP, maybe a little more if it didn't interfere with my throat. JM2CW.
And on the eighth day God created barbecue …. because he DOES love us and he wants us to be happy.
Current smokers: Egor (trailered RF) and Easybake (tabletop pellet drive)
Damn, that's gonna make it a lot harder to weld in... I'm thinking the BP is going to have a drain in the middle and both plates sloped a little bit towards the drain.
Do you think I would get a hotspot if I tucked my FB just to the edge of my CC so that no food would be on top of the FB part?
That's how I've been planning to do it, tuck the FB to the outmost weld seam and stop my racks about and inch before the inner weld seam.
I'm going to cut the doors next week (getting to use plasma then). What's the minimum you would leave between the doors? I have now around 3.15" drawn.
What's the best way to cut the vertical door cuts with plasma? Just freehanding or bending some flat bar for guide? I though of making a circular guide out of plywood that slips on the tank, but that's a lot of work for a guide... The guide would need to be at least 0.5" thick from the tank due to the plasma torch design. It's a PT-31XL torch.
Going to get some steel for the build, what's your opinion on food grates, angle vs square tubing? The lower grates are roughly 30" x 25". I've seen both, but the main difference seems to be that with angle you have two options how to mount the expanded. I remember reading that the grates are easier to clean if the expanded is attached so that the angle is other way around, just can't remember which way. The most common design seems to be that the welding is hidden under the angle, which I think looks best.
One culprit is that I can't find 1" angle thicker than 1/8" here. Would that sag with 30" wide racks? Middle support?
Sorry, nothing to show for yet, it's freezing here (0 F) and I don't have a warm shop.
rikum did you decide to go with the tucked-in FB or a flat end plate?
You might have some wasted height there that you could use for cooking but it depends on which method you are attaching the FB.
And on the eighth day God created barbecue …. because he DOES love us and he wants us to be happy.
Current smokers: Egor (trailered RF) and Easybake (tabletop pellet drive)