T-Burner fittings getting too hot?

[Adam H.]

I fired up my 3/4" T-Burner for the first time yesterday, and there were some issues. First there was some sputtering/popping at random. I ran the burner between 2 and 10 PSI and it persisted. This I figure this is either my mig tip needing adjustment, or my regulator being old... it had sat out in the elements for a couple of years. I figured I would at least give it a shot before buying another one.

 

What really concerned me, however, was that the brass fittings all the way up to the valve hot VERY hot, too hot to touch. This was after only 5-10 minutes of operation, in the exact position shown. This can't be normal, right? What could be causing this? I'm eager to get back to forging but I want to do so safely. Any advice would be greatly appreciated!

 

[swedefiddle]

Good Morning,

Were you running the burner, inside a Forge container? or Were you running the burner in the Air. Too much heat in the burner means the flame was burning back up inside the burner tube. This is caused from too little air flow. Popping and backfiring could also be 'Too Lean'.  Burners run better pointed into a container called a Forge. The tip of the Burner should not protrude inside the FireBox, it should be set back and the stuff inside should be shaped accordingly. one cent + one cent = too cents.

Neil

[Mikey98118]

6 minutes ago, swedefiddle said:

Too much heat in the burner means the flame was burning back up inside the burner tube.

And we know that this is what is going on, because your burner's mixing tube heated up enough for bluing to appear on it's surface.

[Frosty]

Welcome aboard Adam, glad to have you. If you put your general location in the header you'll have a much better chance of meeting up with members living within visiting distance.

2-10psi is way too low. I never run one under 12psi and max it around 17. 

The popping and sputtering was the fuel air burning back into the mixing tube. When it pops it forces the burning mix out of the mixing tube so it has to reignite and do it again.

Your build looks pretty good from here so it was likely inducing very close to the proper ratio of combustion air to propane so when it burned back it was a HOT detonation (pop). What size mig contact tip is in it?

Try turning the pressure up and putting it IN the forge, it's hard to tune a T burner properly in a different place than it's intended to run. Think of it like adjusting a carburetor at sea level to run the Pike's Peak race. Hmmmm?

Frosty The Lucky.

[Adam H.]

Swede, Mikey, Frosty, thank you for getting back to me so fast and for the welcome. I will try to answer all of the questions in order:

The burner was in fact outside of the forge container, as it is still drying, and I am also still mulling over what angle to have the burner inserted (I left out making the hole, as it can be easily added, the forge vessel being made of 2600 rated IFB).

It definitely makes sense that it would run differently inside the forge; I suppose what I was looking to do was try to see if I was getting a good looking flame. Also I was just really excited to fire it up, ha ha.

 

If it helps, I was following the parts list from this video (save the other bits with patina; those are reused from my first burner, which was a gas hog and way too big for my new forge): https://youtu.be/dXFcwheId9I

 

I will give it another shot, this time in the forge, before I try adjusting anything. I ought to expand on the reason I mentioned prior for the burner not being inserted into the forge yet. As I said, I am having trouble making up my mind on the angle. 

 

 

 

 

 

 

This is the forge I cobbled together. I did not feel comfortable handling ceramic wool, so I went with IFB instead. I am on a bit of a budget, so I tried to stretch 4 2600 degree rated bricks as far as I could. The sort of jigsaw looking fit is what was used in the final build. I had one 2300 degree brick left over from my first forge, so I used it to add more insulation in the corners; I figured being away from the actual hot interior, their lower rating and relative fragility wouldn't be too big an issue. You can see in the photo that I ended up with something a little different than the drawing. I decided that I wanted something to put in the front and back of the opening of the forge, so I saved half of that 2300 brick for that purpose, rather than sawing it into quarters like I had planned. I wanted to keep at least 2.5" of insulative material at all angles though, so I used the sawed-off rods of the 2600 degree IFB I was left with after cutting the joints into the brick. They weren't quite tall enough, which explains why it looks like an adobe building instead of a box.

I ended up mixing way too much satanite. After everything was together, and not wanting to waste it, I just kind of... slathered it on the outside. Trying to offer as much structural integrity as I could, remembering how my previous forge of 2300 IFB crumbled to bits after a summer of use. I'm sure this will do little to stop this one from meeting the same fate, and the whole mess will probably serve no other purpose than being a big heat sink and flake right off... But it at least makes me *feel* better, ha  ha.

But enough of my justifications for what is probably a poor build. Like I was saying, I am unsure of what angle to go with inserting this thing. The pencil in the photo shows my current thinking. Trying to bounce the flame off the roof, onto the left wall, and hopefully spiraling to evenly heat the forge. In theory. The internal volume of this thing is so small, I don't know what will happen. But as long as it can make stock removal blades hot enough to quench, that is all I need it to do. 

I didn't mean to write an essay, but my fingers got away from me. In short, I plan to take all of your advice, and try running the burner again in the forge at a higher PSI as Frosty mentioned. To that end, am I on the right track with the angle I had planned? Is the tiny internal volume of this little monstrosity going to cause headaches?

Thank you all in advance, I really appreciate it. I have a friend getting married in late August, and I promised the happy couple a chef's knife as a wedding present.

EDIT/P . S . : I forgot to mention, Frosty, I am in the CNY/Upstate NY area.

[swedefiddle]

Good Morning Adam,

Put your general location in your Avatar, nobody will look back and see your note.

There are quite a few very knowledgeable groups and members in your area. Depending where in upstate NY area, if you cross the border, the Canadian CanIRON Conference is at Fergus, Ontario. August 3-6, 2023. see www/caniron.ca  for details.

Neil

[Frosty]

Well, about your build Adam. You've done a pretty good job of following the video. I'm afraid inserting needless flare fittings is becoming an institutionalized myth. The ONLY reason for flare fittings is IF you're running copper tubing to the burner to prevent heat damage to rubber hose. If you rebuild this one or build another skip the flare fittings and keep all the brass fittings to a minimum. 

Now the bad news. Putting a 3/4" burner of any kind in a 58 cu/in forge is a deal breaker. It'd be like putting a 455 cid V8 engine in a Mini Cooper. Sure you could shoehorn one in but the poor car would probably roll over when you started the engine.

3/4" T burners CAN be made to work in forges as small as 250 cu/in but the dragon's breath is really large. Any burner no matter what type must have room to breath. No matter how you mounted one in the forge as drawn the opposing flame face is so close the back pressure would cause serious problems, even with both ends wide open. 

You need to either buy more K-26 or the equivalent IFBs and enlarge the forge to 300 cu/in, or build a 3/8" burner for this one. 

Frosty The Lucky.

[Adam H.]

I may have to go with the latter option and enlarge the interior, then. I was planning on doing so eventually anyway, after getting through this one project. I remember in my research that you had stated the smaller the burner the harder it gets to make correctly; I tried my darndest to get everything perfectly neat and straight with this one, but to my eye I am not entirely sure I succeeded. I'm sure it'll function, but it'll never be flawless. 

How thin do you think I can afford to have the walls of the chamber be, when I go and enlarge the interior?

[Mikey98118]

6 minutes ago, Adam H. said:

I remember in my research that you had stated the smaller the burner the harder it gets to make correctly

Actually, those are my words; but I was talking about Mikey burners, which get pretty intricate to construct in sizes smaller than 3/8". Switch to a simple linear design, and everything gets much easier (and cheaper) with smaller burners

It is a mistake to assume that construction factors remain the same in burners of various sizes of different designs. You only need to consider how much of any given burner consists of repurposed parts, for that idea to go up in smoke. 

[Frosty]

Yeah, burners are like everything else, the smaller it is the closer the tolerances. Miss a measurement by 1/4" on a pasture fence is silly thinking about it, miss 1/4" on a wristwatch and it's scrap. Have you measured the IDs of the plumbing parts you're using? The inside of a T fitting is rough and irregular. What they do only needs to serve the purpose, flawless isn't even visible from their ball park.

If you're building a brick pile forge the thin side of the IFB is good enough, it's 2 1/4" thick and for the ones I see running for hours at a time I've never seen the outside get hot enough to char a piece of paper.

While I applaud caution, there is no good reason to be afraid of ceramic blanket refractories, even the hazardous types. You just have to handle them the right way up to and including encapsulating the fibers before applying the flame face. The other types, Insulwool being one (If I got the right one) are not persistent in the body, meaning your lungs can safely dissolve and expel any fibers you inhale so unless you powder a bunch and deliberately inhale it the stuff won't hurt you or yours.

Frosty The Lucky.

[Adam H.]

2 hours ago, Mikey98118 said:

Actually, those are my words; but I was talking about Mikey burners, which get pretty intricate to construct in sizes smaller than 3/8". Switch to a simple linear design, and everything gets much easier (and cheaper) with smaller burners

It is a mistake to assume that construction factors remain the same in burners of various sizes of different designs. You only need to consider how much of any given burner consists of repurposed parts, for that idea to go up in smoke. 

Ah! My apologies, I had been combing through so much it all just sort of mushed together. 

 

2 hours ago, Frosty said:

 Have you measured the IDs of the plumbing parts you're using?

I left the burner at work, so I can't get a measurement right now, but I want to say it's 1/4" ID pieces? Would it be possible to re-use the brass pieces and get some more black iron pieces to downsize to, say, a 1/2" burner, while also expanding the interior of the forge body? 

Short of that, I may have to go back to the drawing board with this one, and order more brick like you said.

 

[Frosty]

I wasn't serious about you measuring the plumbing it was rhetorical. I only meant to illustrate how futile precision can be in a way you can check easily. 

Sure, the fittings are the same at least down to 1/2" Ts I don't know about smaller. A 1/2" T has an output about 3x your concept sketch volume.  These things scale at the square of the diameter. Up or down.

I build burners based on basic ratios as laid out in the T burner plans I posted here. I developed using mig tips as gas jets through trial and error the first time. Afterwards they scale pretty parallel with tube diameter. 

Below is a pic of a no weld propane forge the club built in a 2 day clinic. One day we built a bunch of 1/2" T burners, the next we built something like 80  clamp together brick forges. each forge is around 175 cu/in and IIRC cost members about $110 ea. including regulator, hoses, fittings, brick, plumbing and a good kiln wash. The club bought in bulk and only charged members a modest profit.

A number of members are professional bladesmiths and several stopped using their old commercially made forges for these. I may be the only guy in the club that didn't make himself one.

Pic below.

Frosty The Lucky.

 

 

[Adam H.]

Welp, looks like there's nothing left to do but go back to the drawing board on this one. That's a bummer, it's going to be a real crunch to finish this project in time, but I think I can pull it off.

Thank you everyone for the input! Next try will be better.

[Mikey98118]

You already have the small forge mostly completed right? You obviously intended to use this very small forge size. You have a completed burner that can be used in a larger forge, which you don't have to construct right away. The burner can just be put aside for now. The cost and work to build a 3/8" linear burner is quite minor. And linear burners have a generous turn-down range, so this size burner in a linear design will work fine and dandy in your present forge.

The question is, which will be more unsatisfactory; building a second forge right now, or building a second burner, instead. Either way, you will end up with two burners in two forges. And, either way, you will end up better off for it...over time

[Frosty]

 I was getting carried away wasn't I Mike? I think building a 3/8" burner is WAY more practical and economical. 

Frosty The Lucky.

[Adam H.]

2 hours ago, Mikey98118 said:

You already have the small forge mostly completed right? You obviously intended to use this very small forge size. You have a completed burner that can be used in a larger forge, which you don't have to construct right away. The burner can just be put aside for now. The cost and work to build a 3/8" linear burner is quite minor. And linear burners have a generous turn-down range, so this size burner in a linear design will work fine and dandy in your present forge.

The question is, which will be more unsatisfactory; building a second forge right now, or building a second burner, instead. Either way, you will end up with two burners in two forges. And, either way, you will end up better off for it...over time

Can you explain a little more what you mean by a linear design? Between the two, a new burner would be way more preferable! 

[Frosty]

Below are images of basic "linear" burners. Linear refers to the air intake and propane (primary) jet being in a line.  A "jet ejector" has the air intakes at 90* to the primary jet. Commercially jet ejectors are used to draw vacuum, not blow flame into things. What makes an ejector such a good choice for a propane burner is how much greater their induction is compared to a linear. IIRC a jet ejector induces around 27x the volume of the primary jet. A linear induces around 17x the primary which means you actually have to de-tune a jet ejector to make a good burner.

Does that help?

Frosty The Lucky.

[Mikey98118]

Linear burners are the ones that have air entering from a rear opening; that opening nearly always has a reducing shape (ex. funnel, pipe reducer fitting, etc.) attached to the opening. This funnel shape is only there to start incoming air to swirling; thus providing sufficient mixing of the air with the burner's jet of compressed fuel gas.

Other burner designs, such as Frosty "T" burners, or Mikey burners have air entering from the burner's side openings, of one sort or another. We label them as jet-ejector designs. Jet-ejector burners are capable of inducing considerably more air from any given gas jet then linear burners.

However, linear burners are the natural choice for having their vortex motion enhanced with fans that have impeller blades, which starts to lead us far off topic, so I will end your answer here

Burner design over the last twenty odd years has been something like a horse race; neck and neck at times, with one out front, and then another...

[Buzzkill]

On 7/21/2023 at 11:40 PM, Adam H. said:

This I figure this is either my mig tip needing adjustment, or my regulator being old... it had sat out in the elements for a couple of years.

Is it the regulator or the burner that sat out in the elements for a couple years?   Either way, one of the quickest and easiest things to do is ensure that nothing has restricted the opening of the mig tip in your burner.  Debris or tiny critters can restrict or deflect the gas stream.  That can also produce the sputtering flame that burns inside the mixing tube.  If your regulator has been compromised it could be part of the issue as well.

When we were young Dad always told us "Check the easy things first."

[Adam H.]

5 hours ago, Frosty said:

Below are images of basic "linear" burners. Linear refers to the air intake and propane (primary) jet being in a line.  A "jet ejector" has the air intakes at 90* to the primary jet. Commercially jet ejectors are used to draw vacuum, not blow flame into things. What makes an ejector such a good choice for a propane burner is how much greater their induction is compared to a linear. IIRC a jet ejector induces around 27x the volume of the primary jet. A linear induces around 17x the primary which means you actually have to de-tune a jet ejector to make a good burner.

Does that help?

Frosty The Lucky.

 

 

5 hours ago, Mikey98118 said:

Linear burners are the ones that have air entering from a rear opening; that opening nearly always has a reducing shape (ex. funnel, pipe reducer fitting, etc.) attached to the opening. This funnel shape is only there to start incoming air to swirling; thus providing sufficient mixing of the air with the burner's jet of compressed fuel gas.

Other burner designs, such as Frosty "T" burners, or Mikey burners have air entering from the burner's side openings, of one sort or another. We label them as jet-ejector designs. Jet-ejector burners are capable of inducing considerably more air from any given gas jet then linear burners.

However, linear burners are the natural choice for having their vortex motion enhanced with fans that have impeller blades, which starts to lead us far off topic, so I will end your answer here

Burner design over the last twenty odd years has been something like a horse race; neck and neck at times, with one out front, and then another...

Oh, okay! I mistakenly thought those were just another take on a Venturi. I had no idea the different designs did different things, neat!

 

5 hours ago, Buzzkill said:

Is it the regulator or the burner that sat out in the elements for a couple years?   Either way, one of the quickest and easiest things to do is ensure that nothing has restricted the opening of the mig tip in your burner.  Debris or tiny critters can restrict or deflect the gas stream.  That can also produce the sputtering flame that burns inside the mixing tube.  If your regulator has been compromised it could be part of the issue as well.

When we were young Dad always told us "Check the easy things first."

The regulator, I'm afraid. I thought everything was sufficiently covered, but as it turns out, it wasn't. The mig tip I made certain was clear of obstruction after cutting and filing down, but I've read today that teflon tape can end up being cut to ribbons that hang outside of the threads on the inside? 

[Frosty]

Yeah, we make different types of induction devices make flames for us. Common terminology is to call them "Venturi" burners but truth to tell there isn't a venturi anything in them. They operate on aspects of the same principle that makes a venturi work there's just not a one there. The misuse of the term has become so prevalent I gave up on arguing it long ago. I'm not calling you on it I just mention it once in a while as a FYI.

You should check out the "Frankenburner" burners they're serious improvements over much of what you see out there. They're just tricky to make, as in 3D printing and casting. Still, they're real performers.

Frosty The Lucky.