DIY Double Butt Strap Hood

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Deadalus

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Title probably got your attention! This is a double butt strap riveted hood. When I was looking to get back into brewing several years ago I bought a set of three kegs to set up a three vessel system. I didn’t do anything with them for a while. Then I really became committed to getting back in and I picked up a two burner three vessel system from a guy getting out of the hobby. He had 3 keggles and also two extra kegs that I picked up in the deal. I started out on propane with that system but then converted (and polished) the keggles to electric. I thought about tinkering around and assembling a gas system with the leftover kegs but somewhere along the way I decided I could make a hood out of them. So I did!
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Originally I was planning on strapping the pieces together as they are now and using bolts and nuts. I don’t have a welder and I haven’t welded since jr. high. I got to wondering however about the different ways to attach metal plates together and that’s when I hit on rivets as an option. I also hadn’t riveted anything since jr. high either but I figured it would be easier than welding it. Maybe not once I got to figuring out spacing and rivet sizes but it worked out for the most part.

Part One-Main body build.
This build required two kegs. I first polished the kegs but l left off the final polish. I have a pvc stand I use to polish them and it seemed like that would be easier to do than after they were cut. I picked the best keg for the left and right pieces and the other keg for the middle and straps. Straps aren’t usually the same thickness of the main body of the piece but I felt that having the curvature present in the straps would help. Kegs were polished used an angle grinder, 3 different grit flap wheels, and flat felt polishing discs with black and green polishing compound. I only used the first two flap wheels on the worst nicks and scratches and did a full pass with the last one. Then black polish followed by green. I cleaned the edges up with a grinding wheel and a Dremel as best I could but hey, that’s what the straps and edging is for!
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After the second to last polish, I cut one keg in half top to bottom. The second keg I cut the top and bottom almost all the way off and then cut it lengthwise. I left some tabs to finish it all at once. Then I cut the straps from the last half, leaving everything but a few tabs connected then I finished cutting each strap out. The one area I didn’t get deep into was calculating the loads on the parts. I was going to go with four in a row hoping that would be really strong but this would have required keeping the ribs in the straps so I reevaluated and cut them narrower. This left two rivets to a row (and ½ as many holes to drill). I was able to lay out four straps sans ribs on the second half of the second keg. Kegs were cut with a cutoff wheel on a 4.5” angle grinder.
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I laid out the rivet spacing on the two top straps then drilled the correct size holes (#21 drill) for the 4mm stainless steel rivets. I bought a cheap set of ten bits thinking that would get me through. It did not. I had to order another set, this time from Drill America which were surprisingly good bits. I did use a punch and pilot holes before moving up to the #21 bit.
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The first double strap gave me some trouble riveting which only shows on the underside. I suppose a plasma torch would have cut real nice but the cutoff wheel and my not exactly clamping the keg down led to a slightly wavy strap on the top of the joint. The underside strap was also a little thinner in width. I wasn’t able to effectively clamp the two straps and left and right pieces together well towards the middle of the joint as I only have basic woodworking clamps. I tried duct tape but the straps were slightly off and on the bottom (inside of the hood) I missed a few rivets into the second stap. Not noticeable and still riveted fine from the top but I can live with it. I took a different approach with the second double but strap. I left off one side of the hood and clamped the two butt straps to the one side. Then I completed the drilling through the one side of the body and the bottom strap. I riveted those parts together, then slid the other side into the slot, drilled the remaining holes and riveted. I suspect that violated riveting procedures but it’s not a boiler holding pressure. All in all, the two joints came out strong, I can lift the hood from one end and no problems.
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I cut the holes for the lights’ electrical and mounting posts using a knockout punch and step bit. I was a bit annoyed that I needed the step bit after buying the punches as the pilot hole needed for the punches is large. I got both from Harbor Freight though and so not particularly expensive. The exhaust hole was cut using a sawzall. I tried using a jigsaw with a metal bit but no go I gave up quick. I drew the line at buying a 6” hole saw, although it would have been helpful on cutting the exhaust hole in the garage.
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The edges I trimmed with a wider rubber trim. There were a few spots were I had trouble with the cutting wheel, particularly cutting through the top of the keg, and the trim covers those up nicely! I went with gorilla glue to get the trim to lay flat but I had to clamp it overnight and that was just lengthy as I don’t have enough clamps for the length of the perimeter.
Hood is mounted on 1” stainless steel tees and 1” NPT stainless steel flanges. I tapered the 1” going into the inside of the hood.
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Part 2 –Electrical
A weatherproof circular junction box is connected using a ¾” x 1” nipple at the bottom of the tee. I used a ¾” conduit ring to tighten up the tee to the hood on the inside, then attached the box. There are two vapor proof cage lights holding one regular bulb each. I spray painted the lights to match the inside, roughly, they were white to start with. Power comes in from a small junction box in the ceiling, which the flange covers. I used a flexible liquid tight conduit between the tees to bring power to the second light. I installed two Govee color changing bulbs. These are wireless/bluetooth and work off their app. They do scenes and can change with nearby music. I have a wall switch as well to turn them on.
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I was going to add in a junction box in the ceiling for the fan but instead I added a duplex to the receptacle I branched off from as the cord is long on the fan and I need the switch that comes with the fan to set the speed anyway. So I can’t get away from a cord.

Part 3-Exhaust

Exhaust fan is a 6” Cloudline inline fan, it has 8 speeds, no humidity control. It’s quiet up to about level 6. By quiet, I mean it’s no louder than my March pump. It’s fine at high speed, it’s up in the joists. When I finish the garage I will build a box around the duct with a cover. At that point, I could soundproof it if needed but I doubt it would be necessary. I haven’t brewed yet but I was using my HLT to heat up some PBW to clean my jockey box and then went to dinner. I didn’t hook up the pump and the fan was on 2. Well I came back to a steamy mess but I was able to clear it out upon turning up the fan. I think max is 402 cfm and that works fine.

The duct work is 6”. I had to cut a saddle connection from the straight first section by hand. You can get a custom saddle connection, say 6” x 16” (could be 18” diameter for the keg?) but it would cost > $50. I traced the curves with a sharpie then cut with snips. The cloudline has male ends on both sides. I wasn’t thinking fully and cut the saddle for the hood connection on the male end of the straight piece of duct. I needed a short straight piece after the elbow which I cut from the first straight piece, so it didn’t have a crimped end. I used needle nose to crimp that since a crimper tool is expensive. It came out good, but if you need one, maybe borrow that tool from a friend if possible.

I cut the exhaust hole with a sawzall. I had to go through aluminum siding then wood siding then sheathing and the band joist. It was about 4” of wood! Luckily I had a big blade, the extra big one that comes in the blade multipacks. I thought I had the hole well situated but I noticed once I had most of the whole cut that the inline fan bulges at the main body and might potentially bump against the floor over the garage. So I had to work the hole down a little. Also, with the big sawzall blade, I had cut at a slight angle which is exaggerated with a longer blade. My whole was more conical at the back than cylindrical. A little foam will fix that, plus I have insulated the band joist with panel foam in the garage. There is a damper on the exhaust vent too to keep cold air out.

Eventually, I will sheetrock the garage. I’ve covered a lot of the build but if there are any questions feel free to ask.
 
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Deadalus

Deadalus

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I had to move a water line when I installed the hood. I have always been jealous of people having a pot filler near their rig. Since I have an RO system, I dropped a line and installed a spigot when I reconnected the water line. I have a garden hose adapter attached to the RO water supply in and I will be running the waste water over to a sink. Eventually, I am going to run that line to my rain water tank for use in the garden. I finally put that new site glass on and fixed that top ball valve that was weeping too.
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I had to move a water line when I installed the hood. I have always been jealous of people having a pot filler near their rig. Since I have an RO system, I dropped a line and installed a spigot when I reconnected the water line. I have a garden hose adapter attached to the RO water supply in and I will be running the waste water over to a sink. Eventually, I am going to run that line to my rain water tank for use in the garden. I finally put that new site glass on and fixed that top ball valve that was weeping too. View attachment 763323
Man those kettles are pretty...
 
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