Shroud/Windscreen for KAB6 Banjo Burner

Here's what I cut out of a 16" metal duct for my windscreen/shroud.

I haven't done tests yet re: with/without shroud, but between a 2k heatstick to heat my mash/sparge water & to preheat my 1st runnings combined with this shroud, I think I used considerably less propane for my last brew..

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Here are results from boil tests:

NO SHROUD: 2 gallons of water @ 57.1F to rolling boil in 6 min, 51 seconds.
WITH SHROUD: 2 gallons of water @ 53.9F to rolling boil in 5 min, 30 seconds.

If someone with the ability to determine the efficiency can analyze these boil times & temps(BTU's etc), I'll add that data here as well. It is definately obvious that the shroud does keep the heat more on the pot resulting in faster boils.

Looks nice...I've been thinking about doing something similar. Did you buy the 16" duct or find it? Where would I be able to buy one?

I had the section of duct laying around at work. It was a stock edged 4' section, so I would assume this ducting can be bought in short lengths.

I'd try your local HVAC vendor - probably be able to hook you up.

It looks larger in the pic, but the gap between the pot and the edge of the duct is only about 1/2".

Have you tried any tests yet? Curious to hear the results...

Maybe could use a little more ventilation...? Don't want it to go boom

Probably a good idea to add some large holes near the bottom to allow fresh air to be drawn in.

Here are results from boil tests:

NO SHROUD: 2 gallons of water @ 57.1F to rolling boil in 6 min, 51 seconds.
WITH SHROUD: 2 gallons of water @ 53.9F to rolling boil in 5 min, 30 seconds.

If someone with the ability to determine the efficiency can analyze these boil times & temps(BTU's etc), I'll add that data here as well. It is definately obvious that the shroud does keep the heat more on the pot resulting in faster boils.

ReeseAllen said:

Probably a good idea to add some large holes near the bottom to allow fresh air to be drawn in.

Click to expand...

Why would fresh air need to be drawn in? The gas and air is mixing at the opening in the inlet.

As far as fumes and exhaust go that is coming out the top and has nothing to do with air being drawn into the bottom...

Am I missing something?

EDIT: as I look at it again I can see how the exhaust might get trapped in the shroud but the fumes would only be carbon monoxide and some hydrocarbons. Correct me if I'm wrong but this wouldnt make the thing go "boom."

SOB said:

Why would fresh air need to be drawn in? The gas and air is mixing at the opening in the inlet.

As far as fumes and exhaust go that is coming out the top and has nothing to do with air being drawn into the bottom...

Am I missing something?

EDIT: as I look at it again I can see how the exhaust might get trapped in the shroud but the fumes would only be carbon monoxide and some hydrocarbons. Correct me if I'm wrong but this wouldnt make the thing go "boom."

Click to expand...

"Sweet and sour like a tangerine. Fresh like a box of Krispy Kremes."

I may have been exaggerating a little with the whole "boom" thing. However, can't argue with safety. It may be unrelated, but check this thread out:

https://www.homebrewtalk.com/f11/warning-keggle-owners-please-read-41422/

That keggle warning has to do with trapped water in the bottom skirt of the kettle. It boils & builds pressure (since there are no drip holes to let out the water/steam) and it blew up. Totally different thing.

There is plenty of air entering the shroud. See the cutout around the air/fuel mixer - there is probably 8 square inches of inlet for air there. Also, I boil on an angled driveway - and wedge up the low side so the BK is level. This allows a lot more air in.

Anyone able to run the numbers on BTU's after I did the boil tests?

Durden said:

"Sweet and sour like a tangerine. Fresh like a box of Krispy Kremes."

Click to expand...

Nice...3 MCs and 1 DJ!

what is the best to make something like this out of? will the ducting sold at HD in a roll work?

I'm curious as to how this would work when it's windy. Will the wind be blocked enough to not affect the flame? You've proven that it is can heat water faster but I think that was more due to less heat loss out the sides of the stand. What about it working as a windscreen?

That's my biggest complaint with this burner is that it can't handle wind at all. I've had to move my brewing into the garage because my porch gets too much wind.

SOB said:

I'm curious as to how this would work when it's windy. Will the wind be blocked enough to not affect the flame? You've proven that it is can heat water faster but I think that was more due to less heat loss out the sides of the stand. What about it working as a windscreen?

That's my biggest complaint with this burner is that it can't handle wind at all. I've had to move my brewing into the garage because my porch gets too much wind.

Click to expand...

thats basically what i'm looking for because i really cant use my burner on my stand without something blocking the wind... i have no wind protection though at all

I should have noted that the boil tests were done on a relatively windless day.

You're right, the stock burner does seem to blow out easily in strong winds, but I speculate that this shroud will help with that issue as well. I wonder if the force of the exhaust/heat coming out of the 1/2" gap, since it is concentrated around the kettle bottom is enough to offset winds - but that is just a thought.

It hasn't blown out on me since I've added the shroud, but I recall it blowing out several times the first day I used the burner shroudless on a windy day. I can't say for sure if the shroud has helped with that issue, but think it has.

You just need to find round ducting that is 16" diameter - that will slip right down on the burner tightly. You could probably make your own with some sheet metal & a pop rivet gun pretty easily too.

Nice. What's the big black pipe sticking into the side?

Also, how about extending the shroud all the way up to the handles of your kettle? I wonder if this extra space would channel more heat to the pot or at least insulate the sides against heat loss?

That "pipe" is a cover that goes over the inlet to the burner where the air adjustment is and the line to the propane tank connects...

riromero said:

Also, how about extending the shroud all the way up to the handles of your kettle? I wonder if this extra space would channel more heat to the pot or at least insulate the sides against heat loss?

Click to expand...

I considered that, but I wanted to leave a little space for the exhaust. The duct is 16" & my mega pot is just about 16" (maybe 15 7/8") so I was concerned with a small amount of space for the heat & whatnot to escape out of there if the ducting came up above the bottom of the pot.