Venting the Banjo with heat shield

user 246304 · Oct 10, 2017

I thought rather than taking another member's thread up with this issue, I'd post it here. Basically the issue is of solving venting issues with a system using the Banjo burner and a wind/heat shield; too close to the vessel bottom without a means to vent you get exhaust pooling and interference with the flame; you also get the potential for flame wrap around, and so heating your valves, thermos, etc.

One solution I've seen, as triggered in a conversation with day_trippr, is to have the back horizontal member dropped 2" to allow the split-screen capability and mounting on the back dropped member, as shown on Brewershardware.com's site:

Seems obvious that it's a great solution. Pity the soul who stands in back of the rig!

However, I'm nervous about losing that back member as a support for my 20 gallon vessels. In my design, I actually employ corner gussets as well (excuse the drafting and writing):

Inviting thoughts on venting, while keeping that back support member - or on why that support member is unnecessary. Because the split screen emptying out the back is a very elegant solution.

brick_haus · Oct 10, 2017

I built the BH version stand to my specs. I mentioned it in another one of your many threads. My stand carries two 20g and one 30g kettles with no problem. Easily boils 23+ gallons of wort using repurposed blichmann burners (propane) that I removed from the original floor burner stands.
I am convinced that the dropped rear support(not really a support!) is superior to any other design, just dont put the stand too close to anything that cant take the heat. My heat shields are flush with the top of the supports.
As is evidenced by the pictures, I have many,many batches on this stand. View attachment IMG_1507676178.820432.jpg

user 246304 · Oct 10, 2017

"Many, many threads." Yeah, I guess so, Brick. I do have a way of dribbling out words - and threads, apparently. No, in all sincerity, you and everyone else - I apologize if I've been less than efficient with bandwidth. Admin and users. (BTW - let me say it perhaps for the last time, I hope enough read it to understand - I have a central nervous system disease that hits my entire body with neurological pain, constant, and nails my ability to concentrate, and my memory, to hell. So if I forget something, don't think I take your contributions lightly. I don't - I really, really appreciate them all. I just may not remember them the same day, much less the next, or more).

But thanks, Brick, that's pretty comforting. It turns out my welder has been busy as hell and my friend said so. He did flake on communication but I understand he's in high demand. At any rate, as much as I want to weld myself, he's a seriously talented and experienced guy. All in, he quoted me $1210 + tax for SS and $850 + tax for mild. That's materials and labor, and I think it's reasonable at $65/hr.

Since I've been made aware, this back venting looks great and I confirm my heat shields from Brewershardware are split and ready. I'd appreciate the thoughts coming but again, Brick, thanks - lends a level of confidence in the idea.

day_trippr · Oct 10, 2017

Meh....Thread proliferation for useful causes is fine with me.
You've single-handedly brought a lot of life to the various forums.
A Good Thing, imnsfho

Anyway...as I said in another thread, I think this build technique - particularly on a stainless frame - is an elegant solution to the exhaust problem while totally avoiding the scorched paint issue that is pretty much endemic to "kettle directly on frame" designs.

Certainly worth serious consideration...

Cheers!

user 246304 · Oct 10, 2017

Thank you trippr. I really do appreciate it. As it turns out my welder is a good guy, busy as all get out, and will work well with me on anything. Takes the thunder out of my learning to weld, maybe, but I'll have to do that maybe after a couple hundred gallons of bitter down me gullet. Not at the same time.

Very close to going with the dropped back member. MUCH appreciation guys.

Edit: Forgot to mention the quotes were based on 11 gauge. Not sure why he got these to me, because I looked back and saw I did pitch 16 gauge, but no matter. So they'll come down some but regardless, they seem reasonable to me. If anything sticks out as weird about the welder's quote, as always, much appreciated guys.

brick_haus · Oct 10, 2017

Please dont think that my mention of your many threads is derogatory. Honestly, they turn out to be very interesting and informative. Inspiring if you will. Some of the best reading on the forum.
A couple notes, (Im a superintendent for a welding company...) welders are quirky people, but if you are patient they will usually do great work for you. And $65/hr is a fair rate.
Please continue sharing your thoughts.

day_trippr · Oct 10, 2017

A real welder could do the rig with 1.5" 16 gauge and save you a little $$$
I went with 1.5" but 14 gauge as burn-through insurance because aside from practice on scraps it was literally the first thing I had ever put a MiG to

Cheers!

user 246304 · Oct 11, 2017

brick_haus said:
Please dont think that my mention of your many threads is derogatory. Honestly, they turn out to be very interesting and informative. Inspiring if you will. Some of the best reading on the forum.
A couple notes, (Im a superintendent for a welding company...) welders are quirky people, but if you are patient they will usually do great work for you. And $65/hr is a fair rate.
Please continue sharing your thoughts.

Brick, I'm sorry, I didn't mean to convey that - it was a sincere lookback like, man, I've created a lot of threads! And - that I'm aware bandwidth is precious, just hope they're worthwhile to people. Thanks for the kind words, buddy. And for the welding guidance. Without anything to compare it to, just my gut told me his price was very fair, so I was heartened to get his quote. I'm not sure how much will come down in materials when he quotes for the 16 v. 11, but either way, I think he's a good guy and I know he does good work. Close to or some over $1K for a ss rig all in, seems very much worth it, to me....

To say I'm itching to get brewing is an understatement. :tank:

user 246304 · Oct 11, 2017

day_trippr said:
A real welder could do the rig with 1.5" 16 gauge and save you a little $$$
I went with 1.5" but 14 gauge as burn-through insurance because aside from practice on scraps it was literally the first thing I had ever put a MiG to

Cheers!

That was your first rig you welded? Man, nice job, trippr! I am a bit bummed to be handing this over to another, but also glad that's one thing I can tick off my plate, in a way. My local welding supply place lets you rent gas, but only 300#, at 1$ per day, for the tank. The gas, however, a He trimix, is $346. I'd either blow through that by screwing up my CFH, or doing a lot of learning, lol. Locally, anyway, it doesn't seem like renting a mig for ss is done...at least I couldn't find any. Closest was an Airgas rep, but it was Chicago - for me, close to 3 hours each way.

Anyway, for more than one reason, seems fated this welder will do his thing.

I did think to actually drop down in dimension, but if your using 14 gauge was your redundancy factor (How I lived on my first rig, I'll never know - 1st mig, mild steel, 1x1, 16 gauge), I think I wanted to keep it at 2" square, just, well, so I can stir with confidence.

user 246304 · Nov 14, 2017

brick_haus said:
I built the BH version stand to my specs. I mentioned it in another one of your many threads. My stand carries two 20g and one 30g kettles with no problem. Easily boils 23+ gallons of wort using repurposed blichmann burners (propane) that I removed from the original floor burner stands.
I am convinced that the dropped rear support(not really a support!) is superior to any other design, just dont put the stand too close to anything that cant take the heat. My heat shields are flush with the top of the supports.
As is evidenced by the pictures, I have many,many batches on this stand. View attachment 416842

Just re-reading this thread guys, thinking.

Firstly, just want to say, thanks for your kindness. It's one of the things I love about communities like this. Generous folks, and the two of you are among the most. Thank you again.

Secondly, Brick, sorry if I spaced this somewhere, but would you mind telling me what gauge you have there?

Finally, one thought that came to me - with the BH style stand, as Brick, you have - do either of you have any concern about losing heating, to your vessels - that a lot of it is lost out the back and not to your vessel bottoms?

Thanks.

brick_haus · Nov 14, 2017

Mine is 16g 2" stainless. Stick welded by none other than the infamous Francisco (The senior welder at the welding company that I work for)!
I have no scientific evidence regarding the heat loss issue, but my high gravity brews get to boil pretty quick, even with 22.5g starting volume. I get almost four of these batches(90 min. boil) out of one 5gallon propane tank.
That seems very efficient to me.
I think there may be more heat loss out the back, but more overall generated heat resulting in a net (significant) gain in efficiency.

user 246304 · Nov 15, 2017

Great, thanks, Brick. Stick on your stainless - you mean, arc, SMAW? That's pretty compelling evidence stick can do just fine on stainless, if so!!!

user 246304 · Jan 12, 2018

day_trippr said:
A real welder could do the rig with 1.5" 16 gauge and save you a little $$$
I went with 1.5" but 14 gauge as burn-through insurance because aside from practice on scraps it was literally the first thing I had ever put a MiG to

Cheers!

Searching for heat shield stuff I came back to ... my own thread.

First, apparently my insurance lapsed, because I've got a mine field of burnthroughs on my 14 gauge mild! :rock:

Secondly, looking for a proper self-drilling screw to mount the heat shield (Home Depot doesn't have any; Amazon has modified truss head #10's-16, with #3 drill point, 3/4". I don't there there will ever be a point where the screw will have to drill through both the heat shield's stainless and the tubing so suspect this screw is overkill, but early looking brought this up. Will it serve?

Finally, can't recall where, but someone brought up an interesting point not to use screws to mount the heat shield - that the constant intense heating and cooling will eventually weaken the screw's hold in the tubing metal. They recommended GMAW. Problem is, as most know, I only have flux core. Suggestions in light of this info?

day_trippr · Jan 12, 2018

I always drill suitable holes for sheet metal screws. Trying to get any screw to actually drill its way into 14ga doesn't seem practical, and you'd still need a clearance hole through the shield.

I doubt there'd be a practical problem over time using screws - you're just mounting screens, not pot rests, yes? Any decent sheet metal screw size 10 or so should work fine.
But I also don't see a problem tacking the shields to the frame.
Whichever feels good, go for it...

Cheers!

user 246304 · Jan 13, 2018

day_trippr said:
I always drill suitable holes for sheet metal screws. Trying to get any screw to actually drill its way into 14ga doesn't seem practical, and you'd still need a clearance hole through the shield.

I doubt there'd be a practical problem over time using screws - you're just mounting screens, not pot rests, yes? Any decent sheet metal screw size 10 or so should work fine.
But I also don't see a problem tacking the shields to the frame.
Whichever feels good, go for it...

Cheers!

Thanks trippr. Just so I understand - the only holes I was going to drill on the shield itself are on the "legs," as there are 3 already (I'm sure you know this - I just want to make sure I'm on the same page with you). So, you're just saying, drill pilot holes first, everywhere, right?

I was worried about doing the flux core on the shield, if the only thing I was doing was to do tack welds - given that it's flux core and not a stainless weld, I expected I'd induce corrosion over time and a tack wouldn't be sufficient given how heavy the banjos are. But I'd prefer to weld everything, to be honest. How do you feel about just running a tack in each of the three holes already on the shield, then a small stitch or two along the legs, out to the ends? Would this hold up?

day_trippr · Jan 13, 2018

The thing is the ss shields will be no worse off than the mild frame if you were to weld them together.
Basically depassivated SS = mild steel in that regard, but if you maintain the frame the welded shield spots should go along for the ride.

Yes, I'm all in on pilot holes regardless of material. If I'm doing cabinetry, there are pilot holes. If I'm sticking screws in steel, there are pilot holes. Might even be threaded machine screw holes, depending - there are some of those on my rig for mounting the electric system.

Even if the burners are attached to the screens (I missed that earlier) the dead weight is actually not much at all and it's all on shear regardless of which technique you use to attach them...

Cheers!

user 246304 · Jan 13, 2018

OK, awesome. Many thanks, trippr - very helpful, as usual.

Venting the Banjo with heat shield

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