Optimum burner distance???

[selmerfan]

So, I was over at a colleague's place brewing beer today. We like to make our own from all-grain kits...but that's another story. I was using the burner that I borrow from my father side by side with Matt's burner as we were boiling to wort. I noticed that his boiled much more vigorously than mine, same burner (different stand and mount set-up) I had my valve wide open and could just get a half decent boil, but in no danger of boiling over. I could boil mine over on his at 1/2 open! When we got done and things were cooled down, I wondered why his was applying more heat to the wort kettle than mine was. The top edge of my burner is 3 1/2" farther away from the support structure for the pot than his is. My guess is that this is the reason? Otherwise the burners appear to be the same, not sure on the ratings of each though. Both are turkey fryer set-ups. This might also explain why smelting WWs takes so darned long... Fortunately I can test this with a longer thru-bolt that holds the burner to the mounting bracket and the height is adjusted with a pair of nuts. I just need a longer bolt to test my theory. Ideas? Opinions? Am I nuts?

[captaint]

selmer - There's also an air adjustment in the valve, I think. That could matter a lot. Also, if your flame is longer (further away from the pot) more heat could be created. Then there's the wind factor..... JMO enjoy Mike

[a.squibload]

Just dealing with that this evening. My homemade burner seemed to be inadequate,
took an hour to melt a potful of stickons and plumber's pipe (all soft stuff) (propane bottle pot).
Had trouble keeping the temp up, got a ring of lead stuck to the sides.
Tonight I moved the burner closer to the pot, and made an extra burner as there are
2 valves on my salvaged BBQ valve assembly. (The old burners were kaput.)
Will most likely try again tomorrow.

I know from oxy-acetylene torches that parts of the flame will give different temperatures,
so I'm guessing the blue part of the propane flame should touch the pot?
My burners have about 1 1/4" of blue, and a couple inches of yellow above that.
Inadequate airflow? Maybe too many holes in the burner for the jet size?

On the first burner I made slots near the valve/jet with a cover to regulate the air
'cause I didn't know how big to make the air holes.
Didn't change the flames much open or closed.
BBQ setups I've seen have a fixed set of air holes with no adjustment.
I guess altitude is not a factor with propane?

Thinking if I could get it to burn efficiently I would use less gas,
anyone have the magic formula?

[selmerfan]

captain - I played with the air adjustment most of the day. It was quite windy, but we sheltered the pots pretty well, not perfect, but good. If I open that valve all the way then I would blow the flame out under its own pressure. If I opened halfway it appeared that I only had half of the jets burning. 90% closed I had all jets shooting blue flame and I stuck with it there. I'll keep playing - with this longer bolt I'll be able to adjust the height and see where optimum is at.

[BABore]

Pull the hose and fitting where it goes into the mixer end of the burner. Compare the orifice hole size. That is likely the difference. They can be carefully drilled out with the proper bits and a pin vise. Also, those cheap regulators they put on the TF burners are not all the same. Some have a fairly narrow window of output.

[bobthenailer]

ive run into this on 2 occasions. the spin on fitting on the end of the supply hose that goes to the propane tank wasent pushing in on the check valve in the tank enough to let the full flow of propane out ! it would light and produce a flame but took along time to melt .
I replaced the new female style tank hose fitting with a old style male fitting i had from a old bbq grill .

[pdawg_shooter]

I built my LPG burner so I can inject compressed air into the flame. It is really FAST.

[firefly1957]

Your air adjustment should be adjusted so there is a small amount of yellow to the flame and the flames should hit the pot.

[selmerfan]

That's the trouble - no matter they adjustment they don't hit the pot because the burner is too far away. I stopped in at Fastenal today - the thru-bolt is metric, PITA to find a replacement, but I have a 160mm M6x.100 bolt on order that will be in Thursday morning. Then I should be "cookin' with gas!"

[bumpo628]

How about a picture?

[selmerfan]

I'll see what I can do when I have time to play with it, but that may not be until next Monday.

[iomskp]

Is your burner the same as the other one is the gas regulator the same, can your regulator be adjusted, are you using the same size bottle, vapourisation can be an issue, as can the injector size the primary air mixing screw the interrupter bolt, also look down the venturi a spider or fluff can effect the burner.

Regards iomskp

[a.squibload]

Here are mine, they do get hot but there's a lot of yellow.
Maybe I need to enlarge the orifice a bit?

https://lh4.googleusercontent.com/_69sguoFlVzY/TYmPrLiejHI/AAAAAAAAAGg/PyN2I79k1bo/DSCF0082.JPG

https://lh6.googleusercontent.com/_69sguoFlVzY/TZ0vmjm6KvI/AAAAAAAAAIM/cPEscBg-Q_0/small%20burner.JPG

https://lh3.googleusercontent.com/_69sguoFlVzY/TZ0vCR68KSI/AAAAAAAAAH8/dzSqwgptm6Y/burners.JPG

[iomskp]

It looks over gased.

iomskp

[a.squibload]

So maybe I need more air? Or more holes in the burner?
When I turn the valve the flame gets smaller but still has a lot of yellow.
I experimented with a sliding cover over slots in the pipe, didn't seem to change
the flame characteristics.

Like the idea of injecting compressed air, I suppose propane will never get hot enough
to hurt the steel pot.
Maybe that would fix it up.

[lwknight]

The hottest flame has no yellow in it at all. The yellow means that there is not enough air.
Propane only burns in a narrow concentration band. It is nothing like the oxy-acetylene that burns in 3% to 96 % concentration.
So I concur that it is over gassed or under oxygenated. Too much air will cause the flame to lift off the burner and probably go out. Too little air makes a lot of yellow flame and soot.

[selmerfan]

Update - I'm cooking lead as I type this. I got a long bolt and raised the burner, and now I have flames just coming up the side of the pot. I also took BAbore's suggestion and compared the orifice's. Mine was irregularly shaped and TINY, so I determined what the other burners size was and ran that bit through my orifice. Not much of a difference, now it's round instead of irregular and I can tell there is a hole there. The difference is on the burner. Now I can run it wide open and run full oxygen mix into it and get all blue flame with just a touch of yellow at the top. The proof will be in seeing how fast this melts WWs now!

[selmerfan]

Alright! So the proof is in the cooking, right? I just melted all of the pure that I had - an 8 qt. dutch ovens worth from the time I typed the previous post until now!!! It is just finishing, I'm going out to making ingots, then starting on the WWs!!!!!!!

[selmerfan]

So this is what it's like to melt lead with a burner that works well....

[Doby45]

My new BassPro fish fryer that I got last weekend seems to have the burner set real low. Like 5-6" below the pot. I think I am going to get it raised up so that it is more like 2-3" form the pot bottom. Should make it more better gooder.

[selmerfan]

Now that I've opened up the orifice I'll be moving the burner back down - not as far as it was, but I was losing heat up the sides of the pot, the center was NOT the hottest part of the pot today, the sides were. But it still melted like a house afire...750 lbs total today running solo with one cornbread pan for the pure lead and one Lyman mold for the WWs - about 600 lbs. worth!

[a.squibload]

...So I concur that it is over gassed or under oxygenated. Too much air will cause the flame to lift off the burner and probably go out. Too little air makes a lot of yellow flame and soot.

Another bit of evidence I left out, the pot is solid black from soot.
Also I'm at about 6000' altitude. It's all starting to make sense.
Iomskp has given me a few pointers, will try 'em and post results.

[cajun shooter]

Look at my post on casting equipment under Banjo burner that I posted on Tuesday. It might help you. You do need more air.

[selmerfan]

Look at my post on casting equipment under Banjo burner that I posted on Tuesday. It might help you. You do need more air.

This is directed at a.squibload, right? No problem with the thread hijack, I got what I needed out of the conversation. Thanks guys! Keep the tips and advice coming!

[midnight]

Doby45, How is your Bass Pro fish fryer working. Did you move the burner closer to the pot? I'm pretty happy with mine. I turned over 900lbs of linotype and range lead into ingots the first week. I happened to have a 24in dia piece of 1/2in plywood around so I bolted the fryer to it. I added 1x4 pine to the bottom to make it thicker and then screwed some 24in flashing almost al the way around to shield it from the wind. I can get five 150lb batches out of a 20lb cylinder. Is that good mileage?

Bob

[Doby45]

I have not moved the burner yet but I plan to. I really like mine so far and I also want to put some wind guard / flashing around mine as well.

[mold maker]

I took 5 gal bucket and cut it so that the burner mtg bolt held it with slots cut for the pot rest bars and a slit for the burner entrance. The upper half of the bucket was cut to nest with the bottom half and comes to just below the pot top. I added air holes in the bottom to adjust the air for the burner.
What all that did was provide a perfect wind shield and hold the heat against the pot. Now no matter how cool or windy, I use lots less gas and loose very little heat. It's even almost pleasent in really hot weather.
I have seen Turkey/Fish fryers from 32000 to 74000 BTUs. Their not all created equal.

[a.squibload]

Thanks Cajun Shooter, good stuff, only I am kinda stuck with the salvaged
regulator, etc. If I can make that more efficient it will cut down the time,
right now it takes an hour to melt down 100lbs of WWs.
Iomskp suggested smaller injectors, when I get a minute I'll tear the valves apart
and see what is in there. Maybe I can modify or get new ones.

It's all kinda experimental for me!

[a.squibload]

Haven't had a chance to change it BUT did get a chance to melt more WWs tonight.
Tried shooting air into the burner tube, used a blowgun with the compressor.
Made the flames almost completely blue (no yellow). Now I HAVE TO change it!

So it's either rig air tubes with valves, or figure out the injectors in the valves I have.
Or maybe make larger burner tubes for more air?
Shoulda got a turkey fryer to begin with.

I opened up one of the valves, there are tiny orifices in there like in a carburetor.
Will call a propane shop.
Thanks again.

[Philngruvy]

ive run into this on 2 occasions. the spin on fitting on the end of the supply hose that goes to the propane tank wasent pushing in on the check valve in the tank enough to let the full flow of propane out ! it would light and produce a flame but took along time to melt .
I replaced the new female style tank hose fitting with a old style male fitting i had from a old bbq grill .

Good point!!! I have done this to a couple of grills that just would not cook well. After putting the old style stem on, they worked great.