Intro: No-weld Double Barrel Smoker V1.1
If by some chance, you searched this site looking to build an UDS, an offset smoker, or a double drum smoker, and found this post before Javin007's "The No-Weld Double-Barrel Smoker (and How to Use It)" go there and read his first. From beginning to end. It's a great read; informative and funny, and the foundation for this 'ible. I built my NWDBS about 3 years ago based on his instructions, with some minor differences from his after thoughts, and some suggestions in the comments section. I used Grapho-Glass rope to seal the doors, a 6" stove pipe to connect the 2 chambers which I then coated with furnace cement, and I used angle iron instead of aluminum tubing for the frame. I also put an axle on one side with four 10" wheels - like a dually. I followed Javin007's firebrick (number and placement), flue, air intake, and exhaust placement design to a T.
It's been a little over 2 years since completion of the build, and I'd estimate I've used it 20-30 times. At least a couple of those cooks were scheduled on days that took last minute weather turns, necessitating a pop-up canopy for cover. I've cooked chicken a couple times on here - breast and wings, but I still haven't put any beef in it yet. Boston butts are most typical. As few as one 6lber, and as many as six - about 40lbs. I use jessyratfink's Dry Rub and cook til I reach an internal temp of 198-200. Most of the time it takes 9-10hrs to reach that temp.
At the end of last fall, I noticed a couple things that I thought needed touching up. I found gaps in both of my doors preventing a good seal in either chamber. Even with a welding blanket draped over the cook chamber, the temperature varied quite drastically. Paint was flaking off the rear of the fire chamber. No matter how much I tightened the bolt for the air intake vent, once it reached temperature, it expanded causing the vent to fall. Even with my air intake completely closed, I saw temperatures rise. Using a stick to prop the firebox door as forcefully closed as possible, didn't fix this problem either.
After my first use this spring, I saw cooking chamber temps vary from 205-275 degrees. My pig pinwheel allows me to see the speed and direction of the wind from inside my house, and the wheels on one end allow me to easily rotate the smoker during a cook. This helps, but still 70 degrees is too much variance. I decided it was time for an overhaul.
My goal is to stabilize the cooking chamber temperature. I think the instability is caused by air leaks in both chambers. To address this I plan on changing the doors and the air intake. I was inspired by purplewg's The Wild Pig Smoker design. I think having a metal door seals, that are attached to the inside of the chamber, allowing the door to sit flush with the chamber will help eliminate some of the air leaks. In the interest (aka requirement) of keeping the "No Weld" design, I decided to use some high temp sealant and pop rivets. I really wish I had saved the old doors, as they would've made perfectly aligned door seals. For some reason, I threw them away the day I started this rebuild. The plan is to use 2" wide strips of steel that span the lengths of all 4 sides of both door openings. The 3rd barrel I bought when I started this project was used up to make the replacement doors - sized to fit inside the existing door holes. I tried to find the guy on CL that sold me the 3 barrels 3 years ago…but yeah, good luck finding the same person on Craigslist 3 years later. I found a sheet of 2'x3' 22 gauge steel from a big box hardware store in town. Cutting of these 2"xN" as well as the replacement doors was all done with a Dremel and thin Metal Cutting discs. These are not cheap or fast. A pack of five cost over $10 and I went through 2-3 packs for the rebuild. They do cut the cleanest and straightest. My other options were a 4" angle grinder a hacksaw or a Sawzall with metal cutting blades. (I also have a jig saw, but no metal cutting blades). The angle grinder is big and rowdy, and was very hard to make slow precise cuts. The Sawzall bounces up and down misshaping the metal as it cuts it. The hacksaw laughed at me. The only way I could cut 20 gauge (the barrel) or 22 gauge (the sheet) in a straight line was with the smaller Dremel tool and its metal cutting discs. It takes anywhere from 5-10 seconds per inch to cut…so this was by far the most time consuming part of the project. When I built this the first time, I think we used the Sawzall and settled for ugly cuts, because of time. This project really made me wish I had one of these.
For the air intake, I decided that any vent cover design using the existing axis is going to be subject to gravity and heat. To combat this, I moved the axis of the door to the center, and changed the shape to a circle. I cut 1 big opening that would expose all the holes when opened to the max. Then I lined that hole, and all the metal surrounding it with 8' of that Grapho glass rope. Instead of using that (miserable) adhesive that comes in the kit, I used some of my more user friendly high temp sealant to adhere it to the new cover. With some adjustment to the number of washers I used as spacers (on the bolt between the cover and the firebox) I think I've created a pretty good seal.
Lastly I'm changing how I keep the doors closed. A bungee cord with 5lb of barbell weights hanging had been my trick for the cooking chamber door. The firebox door had a small metal tab of scrap metal, connected with a bolt, and offset by some washers. As heat, time and wear went on, I had to use the stick I mentioned above. Clicking around on Amazon one day led me to these, I bought 2 pair - a set for each door.
After all these changes, I'm going to load it up with wood and simulate a good 6-8 hr cook. I'll start without the welding blanket and see how it does. If temperatures still fluctuate wildly even with the blanket, I'll move on to revision 2.0 - insulation. Reading about Rocket Stoves led me to a homemade insulating concrete recipe that should absolutely stabilize my temps, but will make it so heavy, welding will almost certainly be required. If I go that route, I may start over with new barrels. The rocket stove I built with this mix weighs every bit of 60lbs and that's for a 7.5 gallon ash can. Green Egg smokers have the mass and insulation properties that I'm after, but I want to keep the indirect heat/smoke factor, the ability to fit whole logs in my firebox, as well as NOT opening the cook chamber to add fuel to the firebox.
I noticed early in my test burn - about the time I started seeing smoke rolling out the chimney, that smoke was escaping from small gaps a couple places in the cook chamber doors. Trying to bend a curved piece of 19"x30" piece of a steel drum - to match another curve is no easy task. When I set my new cooking chamber door on the updated opening, I saw the curvature didn't match on the lower right side. No problem, I'll just bend it by hand…not so fast. Yes, you can bend steel of this gauge and size by hand, but finding that precise axis and applying the right angle eluded me. Each bend seemed to make it worse. Once I had the handle and door latches mounted, downward pressure on the handle allowed me to nearly match the curve once the latch is closed. The gap went from about a 1/4" before the handle and latch, to maybe a 1/16" - visible, but maybe not noticeable by a casual observer. I hoped I'd minimized the gap enough that it wouldn't matter. Once I saw the smoke, and knew it did, I used some clines to bend my door rests outward, hoping to further close the air gaps. There is another spot near the top of the cook chamber door - among the barrel ridges that also showed a smoke leak. I didn't even try to bend the doors here, I just bent the door rest outward. I worried that I'd need to add more Grapho glass to line the door rests, but draping the welding blanket over the door stabilized temps much better. For the test burn, I was able to keep the cooking chamber temp at a stable 225-230 degrees. With very small adjustments I was able to raise or lower the temperature. I was happy enough with these results to do a cook a few days later.
My burn basket is now too large, since adding the door rests closed that opening down by an inch on all sides. It still fits, but I have to tilt it to get it in. I used to be able to fit my charcoal chimney inside it, so I could dump glowing charcoal on top of the contents of the burn basket. Since that was no longer an option, I bent up a piece of barrel scrap to make this half funnel type of charcoal slide.
I learned on my last cook - before the rebuild, not to include any expensive (flavored) wood chunks in my first fill of the burn basket. I used to line the outside edges of the basket with Apple wood chunks, fill the rest of the basket with charcoal, then dump the glowing coals on the top center when they're ready. I'd wait until the cooking chamber hit about 300 before putting the meat on. I've found that a considerable amount of that expensive wood is burnt up while bringing it to temp. For this burn, I soaked those big Apple wood chunks in a bucket of water the night before (probably doesn't do a whole lot to slow their combustion), I put one log on the flue side of the basket (opposite the air intake), filled the middle with charcoal, and left a gap for the glowing charcoal to be added near the air intake. In theory, this would burn from left to right, hitting the log last and making a nice slow burn. It worked pretty well I guess, next time I may reverse it, to see if the intake air direction speeds up the burning of the fuels. The longer I can get out of the fuel the better. I opened the cook chamber and added the meat (6.5lb Boston Butt) when the temp was about 230. I always try to work quickly when I put the meat in (GIGGITY!) so I don't lose too much temp. The amount of time with the door wide open, while I place the butt, position the cooking chamber thermometer and the insert meat probe into the butt allowed for the temp to drop to 175. After closing the cooking chamber door, I knew I couldn't waste any Apple wood smoke. Opening the smoke chamber door fed the fire more oxygen, I also added some of the soaking wet wood chunks. I think this may be the way to get the most out of a $9 bag of wood chunks. I always get the biggest chunks I can find, that mulch sized stuff burns up way too quick for me.
I had the meat on at about 730a, and by 5pm, the meat temp was still only 185. For the last hour or two, I kept seeing my cooking temp drop to about 208, despite rotating the whole smoker so that the intake was facing the wind. I figured it out when I opened the cooking chamber - either the meat, or the cooking thermometer had shifted while moving it at some point, and the meat was touching the end of that thermometer - so I was more likely getting a meat surface temp than a cooking chamber air temp. I took it out of the smoker and finished it for 60-90mins in the oven at 400 degrees until internal temp hit 200. Once it did, I took it out, wrapped it in foil and let it rest an hour. It was about 730pm when I was pulling it off the bone. It came out perfect by my standards. 12hrs from the time it went in, until it was ready to eat (with the assistance of a 400 degree oven).
I've found that with the size of this contraption, it's capacity, and the amount of fuel it requires, you may be best suited to cook a lot at one time. I use almost an entire 18lb of charcoal, a whole $9 bag of wood chunks, and 6-8 logs throughout this cook. I'd use the same amount to cook a single 6lb butt as I would for 6 of these. In the future I'll probably cook at least 2 at a time.
After this cook, I'm very happy with these mods. It was so much fun designing, building, and testing this project I may make another smaller version. I'd like to incorporate my insulation cement recipe into a single drum aka Ugly Drum Smoker - in a way that would allow me to add fuel without removing the lid.
Step 1: Here Are Some Minor Changes When I Built This a Few Years Ago
Pic 1 shows the Grapho glass used instead for the Sealant. The curing time is much shorter, but the adhesive included with the kit was a nightmare. We followed the instructions placing it in warm water, but it still had the consistency of almost-set Quik Steel. And it was very messy.
Pic 2 shows my air intake - pretty similar to the original design. Notice how it didn't sit flat against the barrel. None of the "flat" surfaces of the barrels were really flat.
Pic 3 - based on Javin's recommendation, I removed some of the paint I knew would be impossible to reach once I'd added the furnace cement to adjoin the flue to the 2 barrels.
Pic 4 is what turned out to be the best tool to remove paint from the barrels. A drill with a locking trigger made it easier to position my hands to apply pressure in all the little nooks and crannies. If I were to make this all over again, I would absolutely strip 100% of the paint from both barrels before I made the first cut.
Pic 5 is after initial assembly was complete. It was recommended that we try to get the Grapho Glass adhesive to...IDK, 500 degrees for 30 minutes for it to completely cure. We had fires in both boxes and maybe saw 400 something in surface temps per an infrared laser thermometer. (Another reason not to use that miserable adhesive, you don't have to do that with the red High Temp stuff I mentioned in the intro)
Pic 6 is after the initial firing. We scraped off the red paint that had bubbled off (with that Quick-Strip disc) - a very-not-fun part of the project, then hit it with 2 coats of High Temp grill paint.
Pic 7 is the last change I made to Javin's design, regarding the flue. I went with a one foot section of 6" stove pipe. I cut a 6" hole in the top barrel, jammed the pipe through it, then traced where it hit the bottom barrel. We got both holes lined up well enough so that the pipe would link them. Since the pipe was a foot long and the gap was only a couple inches, there was a plenty of pipe extending into each barrel. I cut vertical slats on each end and bent them down in kind of a sunburst fashion, in an attempt to improve the fit. With the tools we had available, these cuts resulted in a fit that was nowhere close to air tight. I bought 2 tubs of this furnace cement and used it on both ends of the pipe, all that I could reach on the exposed area of the flue, and also on the chimney pipe. I'm pretty happy with this material, although I found it did eventually leak grease - when I cooked 40lbs at once.
Step 2: A Few Years and Many Cooks Later, Time for an Overhaul.
Like a dummy, I removed the old doors, and threw them away the day I moved this into my workshop.
Tackling the air intake first, I measured the distance from the center of the drum, out to the furthest hole I had drilled, then added 1" to that. That would be the radius of the new circular cover. Since I saved the 3rd drum I bought for the original build, I still had one good end to source that piece. I stripped all the paint before I cut out the circle. Once I had it cut, I drilled a hole in the center and hung it in position with the machine screws I used throughout the build. With the circle in place, I marked the exterior holes with a marker shown in Pics 2 and 3 .
I estimated about an inch gap around all these holes and drew my cut line you see in pic 4. Pic 5 is how I typically cut the metal - using bar clamps a scrap piece of 1x2, being held down onto an old door - aka my second workshop table. Pic 6 is post-cut.
Pic 7 shows the Grapho Glass and sealant I used.
Pic 8 and 9 show how I put them on the intake cover.
Pic 10 is the new intake handle - just some gate latch I found in between the gate/fence and drawer hardware section of my local big box hardware supply store. Pic 11 shows where the mounting screws for the latch would have come through - in the middle of rope - had I mounted the handle straddling the center axis.
Step 3: Air Intake Vent Continued.
I went a little picture heavy on the Air Intake Vent, I think more than am allowed to add to a single step. Here are some more images and explanations to them.
Pic 1 shows my first guess at the number washers needed between the lid and the smoke box. Pic 2 shows how it looked reduced to 6, and Pic 3 shows the better fit.
Pics 4, 5 and 6 show the various positions - fully opened, partially opened and , and fully closed.
Step 4: Vertical Door Seals
Taking measurements for the top chamber, I wanted the 2 horizontal pieces to go at least an inch farther than the opening, to allow plenty of overlap for the rivets to secure to. I figured 2" was a good width for these seals, so that 1" could be exposed, and 1" should be plenty for the high temp sealant and rivets to hold on to. The exposed inch on each of the horizontal pieces meant that I needed to subtract 2" (17" in my case - Pic 1) from the vertical axis lengths. I measure with a tape measure, so that I could get the true length of the surface, accounting for the ridges in the barrel. A flat ruler would've given a shorter distance, since it's not traversing the waves of the design (Pic 2).
Pic 3 is the tool and my chosen cutting attachment. Not cheap or fast. Definitely use eye protection when cutting metal. As these discs cut, they deteriorate, sending mostly a fine dust, but occasionally a small chunk of the disc flying. I found that my face was routinely very close to the material I was cutting, so that I could see through the safety glasses. I often felt specs of material hitting my glasses and my face. Pic 4 is all of the pieces cut.
I knew the vertical pieces would be much easier, since I didn't need to form the metal to any bends or ridges, so I attached them first. To have a good clean (inner) surface to mount I used the paint remover to clean up the soot from the inside inch around all of both doors (Pic 5). Pic 6 shows the application of the high temp sealant. I think the instructions say it has a 15min work time, so I'd clamp it down (Pic 7) and let it sit at least 17mins before I started with the rivets. I left the clamps in place, and moved them around as I drilled and popped the rivets. I had 2 different sizes of rivets, both 1/8" diameter, and either 1/8" or 1/4" mounting depths. I used the shorter 1/8" mounting depth rivets for most of the lengths of the seals, and saved the 1/4" depth rivets for the corners, where I found the seals had a tendency to bend inward when I drilled the holes. I had never used a rivet gun before this project and was mildly intimidated by the thought of drilling all these holes in something I was trying to make airtight. The gun works awesome, and that combined with the sealant made me think (minus the strength factor) this was nearly as good as a weld. Pic 8 is the end result of that.
Step 5: Horizontal Door Seals
The vertical seals were a cake walk compared to the horizontal seals. I set them in place and held it there with a single clamp so I could start marking the place to bend the metal. Pic 1 shows the difference in length measured with the tape measure accounting for the ridges vs measuring with a flat ruler (each of those lines marked will line up with the inside edges of the door). I didn't mark all the ridges at once because I was concerned that these distances could be off, once I started bending. At first, I just used a clamp and piece of board (Pic 3 and 4) to bend the metal, but I came up with a better way to repeatedly produce uniform bends. There were 2 different sized ridges in the barrels. Drill bits worked great as a guide, since they vary in size and are nice and rigid. To find the right size, I'd set the bits in the ridges on the barrel, and chose one slightly larger than the distance from the peak to the flat plane of the line...which probably doesn't make much sense in words.
Pic 5 is the horizontal door seal after the first 2 bends - using the clamp and wood block method. After those bends, you don't really have the room to keep going and make more bends in close proximity to the others. Pic 6 is the contraption/ method that I came up with to make repeated bends. Although it only shows 3 clamps in use, I did eventually use 4. Also, 2 of the clamps in that picture are quick hand clamps, and don't enable the anywhere near the amount of pressure I could apply with the C-clamps. When I started using 4 clamps, 2 were C-Clamps and the other 2 were Clutch Bar Clamps similar to these.
Pic 7 shows how the seal fits after a few bends.Pic 8 shows the finished piece with all the bends. After applying the sealant, positioning it so that it butts up against the two vertical pieces, clamping it in place for 17 minutes, then riveting it to the chamber - we have Pic 9.
I repeated those processes for the upper horizontal door seal of the cook chamber, then I moved onto the smoke chamber door seals. Same thing here. I did the vertical seals first, so that I didn't have to worry about there being a gap between the 2 seals.
Step 6: Installing the New Doors
If your barrels are anything like mine, they're not straight or regular in any sense of the words. Mine could've served as barrel race obstacles some time between their service as honey containers and pig smokers. Most surfaces were roundish and straight-like. Because of these irregularities, my assumptions that I could cut out a door shape from one barrel, and using the exact same dimensions cut out the same shape in another, and the resulting "door" would fit in the other hole. That assumption did what most of my other assumptions do - cause trouble. I placed the new cooking chamber door in position and found I had to do a good amount of grinding to get the door to fit. In addition to requisite eye protection when grinding metal, I highly recommend ear protection. The sound of 22 gauge steel being slowly reshaped by a coarse-particle aggregate spinning at about 3600 rpms is offensively loud. If I'm only using a bench grinder to sharpen a hatchet, I'll skip ear protection (prolly dumb). To get this big 19x30 inch door to fit, I had to leave it running and go back and forth for test fitting. The first time I did this, I didn't use ear protection and my ears rang the rest of the night. The next time, I re-purposed some over the near noise cancelling earphones for protection - much better.
I reused the same brass hinges since there was nothing wrong with them, and they allowed more than enough travel. Before they had some washers under them, to create space between them and the cooking chamber - to account for the offset created by the Grapho-Glass rope. Now they are mounted flush - Pic 1.
Pic 2 shows how the cooking chamber door sat in its new home. What this picture doesn't really capture is the gap along the right side of the door. On the right vertical side of the door, going down to the corner, the door sat about 1/4" off the door seals. Steel of this gauge and size is pliable enough to be bent by hand, however, I could not find the axis to achieve my desired results. It was weird, like you look at it, you can see how it needs to bend, so you try to bend it, it bends, but the new shape is worse. Like eyes were playing tricks on me. I got it back close enough to it's original shape and used some ratchet straps to secure it flush on the seals. With the ratchet straps in place. I came up with the mounting position for the lid clamps. I had these all mounted up when I notice Pic 3...zinc plated. No dice. A little bit of googling will find results on both sides of the "is zinc plated metal dangerous to use in a smoker" fence. Some say that poisonous zinc oxide gas isn't released until above 1600F, potentially a problem for welding, but if you keeping with the spirit of this 'ible - you're not. Metal fume fever isn't something I'm willing to risk, so back to the hardware store for some stainless steel (Pic 4).
I just kinda eye-balled where I wanted the re-used door handles to go. With the lid clamps installed and the door handle reattached to the cooking chamber door, I was satisfied with the pit (Pic 5). Instead of redesigning the smoke box door handle so that the bracket could be attached to (reduced clearance) door opening, I just cut out some notches in the seals that you can see in Pic 6.
Prior to me taking Pic 6, I tested the bottom door fitment, again using the ratchet strap method to get that door as tightly closed and flush as I could, before mounting the smoke box's lid clamps (Pic 7).
There were some other random holes I found under the bottom hinges that I missed before. I plugged them up with QuickSteel and allowed it to cure. I then removed the doors and the lid clamps and applied 2 coats of some High Temp Grill paint.
Pics 8, 9 and 10 are the finished product.
Step 7: First Burn After My Changes.
I did my first burn as similar to an actual cook as possible but I didn't want to waste expensive wood chunks, and I didn't see the need to test longer than 6 hours. I figured any flaws should be revealed by then. I did use my BBQ probe to monitor cooking chamber temps. I found within a few minutes of dumping the hot coals into the fire basket, and smoke made it's way up out the chimney, some of it took a short cut out of some gaps in the upper door. I covered it with the welding blanket, which at least hid the escaping smoke to the naked eye. My early frustration had me considering more Grapho-Glass, to line my door seals...trying to think of any other way to retain heat without committing to my "2.0" design. The insulated concrete recipe would not only add at least 100lbs (making this bulky contraption less portable - and likely require the frame to be welded) but it takes about a month to cure. Over the next hour or so, I thought of other changes I could make that wouldn't have the smoker out of commission half the summer. Since I didn't add meat, I didn't open the cook chamber, so there was never a drop from 225F down to ~170F. As I thought of other ways to make it more air tight, I noticed that the temperature crept up to about 235F. I reduced the vent opening by about 50% and saw the temp drop down to about 215F. I raised it back up another 25% and got the temp to sit right at 225F. It sat between 225F and 230F until the fuel ran low. So despite the drop in form (leaking smoke), my function (temperature stability) was up in spades. If this were a store bought offset smoker that cost about what I spent to build it (I'd estimate around $500), I'd be a little perturbed about the leaking smoke. Since I built it myself and the end result is (in my opinion) perfect Pork, I pretend the smoke leak isn't a real thing.
Pic 2 shows a scrap of barrel metal that I formed into a half a funnel. After reducing the size of the smoke chamber's door opening, I could no longer fit my charcoal chimney inside to pour the hot coals on top of the basket. This little slide allows me to quickly and safely get the hot coals where I want them. There are a few different ways to burn coals. Before, when the chimney fit inside, I'd dump hot ones on a pile of unlit coals. As the hot coals burn down, they'd light the unlit ones. This happens slower than if the unlit briquettes are put on top of hot coals. Pic 3 shows how I put in my coals for my first cook after my changes. My intent was to force intake air across the hot coals, light the unlit coals that would eventually light the log - a variation of The Fuse method. Once the log was ignited, I then added my expensive (aka not free) Applewood chunks. The previous link also mentions an exterior method of insulation - using Reflectix Double Foil Insulation, that I'm going to consider as well. A trait you'll find in excellent offset smokers like this one, that a 55 gallon drum build will not be able to duplicate on its own is heat retention in the cooking chamber. 20 gauge steel used to make most drums has no where near the heat retaining properties of 1/4" thick piece of pipe. The welding blanket probably helps a lot (I haven't measured the difference), but this quest has me obsessing with heat retention. I have it in my head that the more heat I can retain, the less charcoal/wood chunks/logs I'll need to burn. Less fuel = less cost, less cost = more barbecue. More barbecue = Happy Jef!
In closing, I'd like to give due credit to the architect of this design - Javin007. His 'ible won the BBQ contest on this site, and is mostly responsible for my membership and following of the ideas shared here. Purplewg's Wild Pig Smoker inspired my changes to the design. I intentionally avoided the use of the word "upgrade" throughout this 'ible, out of respect to their designs. I made some changes that have improved my smoker. I was hesitant to create an 'ible that is just a revision of others' great ideas, but I've gotten so much from this website, that I wanted to give back. So I documented my changes and shared them here. Enjoy!