New build first reverse flow

[phathead69]

First and foremost no making fun of my lack of welding and fabrication skills. I built a vertical offset that I current use.

I wanted a smaller offset for smaller smokes and taking camping so I came across an expansion tank and started. Let me know if anything is too far off. CC is fairly thin and FB is little thicker than 16th but not quite an 1/8th. I know it light stuff but trying to keep it " loadable " in to truck. Any thoughts on build so far. It'll be week or so before I get back to it.

CC 16 diameter x 23 long. FB 11.75x12x12.25. Fresh air 3 x 7 with lid I can vary closed to open. Door 8 x 8.


Chimney 3x3x16


FB to CC 3x11

 

[SmokinAl]

Did you run the numbers thru this calculator?
https://www.smokingmeatforums.com/t...moker-how-to-calculate-build-tutorial.268692/
Al

 

[phathead69]

Yes. I'm pretty much on those numbers. One three me was FB to CC. So I made it big knowing I can close it down. Chimney is close. I used the felnors

 

[1215]

Cool. What are you welding with? I'm doing a UDS now and it's a total pain dealing with 10, 16, 18 and 20 gauge all on same cooker. Are you keeping your arcs on the thicker metal? (I assume the angle iron is thicker than the firebox sidewalls)

 

[phathead69]

1215 yep the angle iron is thicker and I roll from it to the thin. It's a millermatic 211. It welds better than my skills. Sometimes with a blood sacrifice to the welding gods and proper moon alignment I produce a good bead.

 

[1215]

I had a blue mm 211 for a bit. That's a really solid machine. The 211 is at or above my skills too :) Only reason why I have a MM 350 is because I sold/flipped the 211 for good money and picked up the 350 for stupid cheap. Also have a red Precision 225. That's a great machine too --and wayyyy over my skills.


Are the angle irons bed frames by chance? Bed frames are spring steel and weld like sh*t (pardon my French). If you are all mild steel you'll be good. You are pushing the puddle right? Push the gun/wire, don't pull/drag it. Just kind of keep your heat dialed in for the thicker stuff and as you swirl the ark, try to push the puddle over just enough to catch the thin stuff. Almost like you want the puddle to be on the edge of the angle iron and roll or push it over onto the thin stuff. Push don't pull.


Is the metal clean? No paint, everything completely stripped and wiped down with acetone? (acetone really makes a difference with splatter) Do you have an auto-dimming helmet with grinding mode? Halfway decent gloves help too. You wouldn't think it would but it does.


If it makes you feel any better I'm trying to extend a 34" 55-gal drum to be 40" long with my red Precision 225. I haven't TIG welded in a while and god I'm basterdizing this smoker... I feel like a 5yo with a glue gun could do better.

 

[phathead69]

Yep clean metal and all. Just one of those things. Most of time looks like bubble gum. I just keep at it. One day I might lay 2 beads in a row.

 

[1215]

I broke out my red Precision 225 tonight. I'm making a clone drum. Pretty cool --double walled, fully insulated, blah blah.. Just easy metal work (which I really like). Something most people don't realize is that the brand name (expensive) drums are TALLER than a standard 55-gal drum... So yeah. I accumulated several (5 or 6) free drums and I'm trying to lengthen a drum. You know how a 55-gal drum has two crimp rings? I cut a section out of another drum and I'm trying to splice that into a drum (that I like the paint/logo on so I don't want to F it up) so the drum looks like it was made that way --just longer/taller with three rings and four sections, not two rings and three sections.


I basterdized those TIG welds so bad tonight I had to get up and walk away. Absolutely terrible. IDK what was going on but I couldn't do it. I think I had the heat/arc right but my hand was cramping up so I was a mess feeding the wire. Was a disaster like I had never welded before. I guess I'll practice a little bit tomorrow and try again. If not I'll GMAW and grinder and paint make me the welder I 'aint...


What are you going to put that thing on? A grill stand? And how are you going to paint it? I have a couple transitions in my drum that go from the inner metal to outside so very hot to ambient air temps. not sure what to do with paint in those places.

 

[phathead69]

Well made some progress this weekend. Got it on its feet.

Got the RF plates in and test run. Initial had +15 to 20 F hotter on the FB end. Found addition of a water tray on that end and temps with in 6F ends and middle. Holds temp pretty good but need to make a few more test runs to dial in my method and timing. Believe my chimney is little on small side and may have to do it over. Been interesting and heck of learning curve. Paint and touch ups next weekend.

 

[phathead69]

Can someone check these numbers. I see I'm a little small on the FB to CC but is it to much. I ran it and it draws but I think it's a little restricted and not sure if it is the opening or exhaust.

 

[phathead69]

 

[1215]

I ran through it and got the same numbers you have. I think you are a little small. For reference, 2x10=20... 2/18.5= 10.8% so your FB to CC opening is roughly 11% smaller than the calcs say to build it.

I think it's better to have too much and dial it back than not have enough. Your chimney is easy. Pick a side --front or back. (pick whichever side has the worst welds :) Use the grinder and grind off one side then reuse that same piece of metal just move it forward (or push it back) and cut out a little more off the rounded CC end. May not be perfect but a grinder and paint goes a long way to hide your sins.

I was thinking you had a round FB so initially I was thinking you could almost "extend" the RF plate over the round firebox to almost square off the top which would get you the extra couple square inches on either side... But you already have a square FB.

What if you took something like a piece of 3/16" x 1-1/2" flat stock, use a torch to heat & bend it then wrap it on a 45 around the bottom of the CC, between the CC and FB. I have no clue how you'd do that math to make it exact but looks like your RF plate to CC numbers are fine so all you really need is about 2" (square inches) more between FB and CC. That would let you grind/cut down a little bit more on the FB side and over a hair on the CC side and should get you at least (guess) the 2" you need. If you can get in the CC and FB, you can weld both sides so no big deal and it'll probably look intentional. Just a suggestion for fairly easy fixes... But yes, I think you are a little small. If anything I'd go big and dial it back.


Also what did you do inside your FB? Are you running a fire basket with an ash tray/pan or are you building a fire/coals directly on the bottom of the FB? Raising up the fire so air can get under might help a bunch too.


Good luck!

 

[phathead69]

Sorry for delay been on vac. So I came up with this to increase FB to CC opening. Gussets and plate.


So I'm going to try a test run soon. I'll chk and see if flow improves. If not then I'll go at the chimney .
Yep I've got it raised. I'll get picks next time.