3/4" burner seems way too big!

[bcrimmins]

Greetings. Working on my first forge. It's a 5-gallon bucket design. I borrowed elements from a few different designs and ended up building a monster burner -- at least I think it's a monster. I'm worried that it's way too much flame to dump into the 375 cubic inch cavity of the forge. Here's a link to a video clip of the burner on it's first firing. Granted, it's the first time I've see one of these things in action so maybe it's not as aggressive as I think it is. The specs are:

• 24 inches of 3/4" steel pipe with a 3/4" to 1" reducer fitting on the end. 
• 30psi Propane regulator (in the video it's at about 75% of that.)
• The Propane orifice is a 1/16" hole drilled into a brass fitting. (I wonder if that's too big?)
• Naturally aspirated with ten, 1/4" holes drilled in the pipe.

https://www.dropbox.com/s/kixcnfdlxgj6rl0/20180715_134019-c.mpg?dl=0

Is this sucker too much?

[stevomiller]

I’m new to gas forges, so not even a wannabe let alone expert.

However, all the dimensions you gave don’t follow ANY 3/4” normally aspirated burner I’ve researched.

Your tube is way longer, and the gas orifice is TWICE the average diameter (so almost 4x the area).

Others with a lot of experimenting with these will give you particulars on your set up.

I, however, can only say read the BURNERS 101 thread, and get some solid info and theory under your belt.

Then build a known working design without your own embellishments: that thread details the T Burner and Mr Porters burners.

 

 

[Buzzkill]

Yeah, that may seem like a massive flame, but it's not burning well (i.e. hot).  We want short hot (blue) flames for a forge. It looks to me like it's way rich on fuel. If you tried to use it in a forge as is my guess is you'd have trouble getting much hotter than a low-orange color at best.   I doubt you will get to 2000 degrees with that burner - at least not without significant modifications. When you get close to right it will produce a load roar. As stevo mentioned, if you'll take the time to read through the Burners 101 thread you'll get a much better idea of what makes a good burner.  We have several gas burner gurus on here and a couple which have designed burners.  They will help you figure out what's wrong and get you burning hot if you do your homework first.

[bcrimmins]

Thanks stevomiller and Buzzkill.  I actually started with the Burners 101 thread. But I see now that I didn't give it a chance. When I first saw that is was 48 pages of posts, and the first half of the first page of posts included a lot of chit chat, I figured it was a great idea (i.e., a consolidated and focused treatment of information on burner theory and design) that devolved quickly. So I didn't read any further. At your suggestions, I went back and gave it another chance. Glad I did. I'm learning a lot and will continue to read the posts. Once I have a better foundation (and perhaps a better operating burner) then I'll pop back in here.

Thanks, 

Bob

[stevomiller]

Bob, you are taking the right approach. You will find that there are quite a few folks here that have spent literally years working through the details of what makes a good NA burner, how to tune them, etc....

[bcrimmins]

Ok, after reading a bunch I came up with a new configuration. I would be grateful for any feedback. I think the dimension are reasonably close but I'll mess with tuning if it works even half-way well. The biggest uncertainty in my mind is the air intake holes. I'm thinking 20 holes, four opposing rows of five holes. Each hole is .3 inches. I would add a choke sleeve to control the volume of air. Switching the 1/16" drilled hole in the brass cap for a .025 mig tip. 

[Irondragon Forge ClayWorks]

On 7/16/2018 at 11:25 AM, bcrimmins said:

continue to read the posts

Have you read this post yet? It will help getting the best out of the forum.

https://www.iforgeiron.com/topic/53873-read-this-first/

 

[stevomiller]

Mike Porter, who literally wrote the book on this type of burner, states that use of holes for air inlet ports is not ideal, that you should use rectangular slots (no arc at the end), and that an odd number (3-5) of slots is better because ports aren’t directly opposed to each other, which can add flow disruption. If you don’t have the means or desire to make said slots, then purchase a 1”x3/4x1” TEE and build a Frosty  T Burner. Like I stated previously, use a KNOWN PROVEN EXCELLENT DESIGN if you want success, they don’t cost any more in materials to build than one that isn’t, why deviate from what others have worked the kinks out of? What you have drawn will work but still isn’t the best use of the materials you have on hand. Once you build a known good (proven and perfected) design, knock yourself out experimenting, you might then end up developing the next great burner.

[bcrimmins]

Thanks @Irondragon Forge & Clay. I hadn't. But, you're right, I should have. And now I did. 

Thanks, @stevomiller. I know you're right. I have a disease: I always want to try to figure stuff out on my own. But your advice is spot on -- best to make one that works well first (so I can make progress on the project I'm working on) and then use that as a launch pad for possibly tweaking and making it my own. This is especially salient advice given that my objective is not to become a bad ass forge builder but, rather, to melt stuff and create art from it.

I'm feeling frosty. 

[Frosty]

If you prefer to experiment and reivent the NA burner why ask us if we think yours are right? So long as you don't cop attitude if one of us who've been making the things for decades makes a suggestion we'll probably still drop a hint now and then. You've already responded to my first suggestion so I won't make it. See Steve's suggestion above.

Frosty The Lucky.

[Latticino]

If you are trying to work out your own burner design, in addition to the ability to easily change the orifice diameter (which you have to some extent by using a mig tip), it is also helpful for tuning to be able to adjust the location of the exit of the orifice in the burner tube.  You will find that with NA burners that makes a significant difference in how much air is entrained.

[bcrimmins]

@FrostyI have high respect for all of you and I would not think of copping an attitude. If you ever sense that I'm being an idiot, I assure you it's just the limits of language typed into a form without sufficient attention paid to word smithing. 

My "I'm feeling Frosty" comment just meant to say that I'm going to build your "KNOWN PROVEN EXCELLENT DESIGN", as Steve referred to it. It is indeed a simple design and one that I had run into in my initial search. At the time I started looking, I didn't realize that burner design was such a practical science; I thought you just had to shoot some gas down a pipe and light it up. Boy was I wrong. 

To be clear, I don't "prefer to experiment and reivent." I just want to build a forge and thought I had cobbled together a bunch of parts that would work. The burner I built seemed (to my uninitiated eye) to belch out such big fat flame and it seemed like it was too much flame to shove into a 5-gallon bucket. When I realized that, I posted her to check my suspicion that the burner I made was not good. Turns out it was not good, but for reasons I didn't even consider -- I thought the burner I built was too powerful... turns out it wasn't even a question of being too powerful... it was just a terrible burner, terrible flame, terrible design, terrible pretty much everything. 

To answer your question of "why ask us if we think yours are right", I just wanted to see if I could use what I had learned to salvage what I had already bought... and tapped... and drilled. But I see from Steve that that's pretty much folly. So I'm reformed. I'm going to build your T burner to get my first furnace built. It's just as likely as not that every future furnace I build will use the same design. As I said before, I didn't realize that the parameters for burner design were so precise and specific. I'll focus my inventor energy on the art I will make from what gets melted in the forge and gratefully leverage the great work you guys have done to work out efficient burner design.

Thanks.

[Latticino]

Good sentiment, but you will have to watch your language on this family friendly forum.  Expect to get moderated...

Love the Frosty Tee design, for what it is, but the key drawback, IMHO, is lack of easy method to tune by adjusting the orifice outlet.  Trimming the MIG tip works, but it is easy to screw up and also modifies two variables simultaneously (orifice length and position), which makes it a little harder to tune.

[bcrimmins]

Thanks, @Latticino  I have cleaned up the post and will be careful.

Thanks also for the thoughts RE orifice location and tuning. I will noodle on that. 

[Latticino]

[bcrimmins]

 

Gentlemen, thank you all for getting me straightened out. 

As I said, I am going to build the Frosty burner. However, Latticinos comment about tuning via orifice position got me to thinking. So I made a minor modification to Frosty's design such that the depth of the orifice can be readily varied for tuning. Here are some pics. Your critiques are welcome.

The first image is a full length view of the burner. The body is a 1" cross. The Frosty calls for a 1" x 3/4" T. But by adding a 3/4 reducer bushing I can accommodate the 6" section of 3/4" pipe. Since the transition from 1" to 3/4" at the bushing adds a dimension step, I recognize that may add some additional turbulence to be accounted for. Is that correct? 

On the opposite arm of the cross, I use a brass 1" x 1/4" NPT reducer bushing, through which I twist a 1/2" threaded lamp  tube. The lamp tube thread count (18) matches the NPT fitting , but the NPT fitting is tapered so I had to tap it with a straight 1/2-18 tap. The threads of the bushing also only went half way through the bushing so I used a step bit to open up the back end so that the lamp tube would pass freely through. To the end of the lamp tube is threaded a 1/4" NPT cap, tapped with a 6mm hole for the MIG tip.

By turning the lamp tube, the position of the MIG tip can be moved in and out to different depths. Here you can the MIG tip in roughly the recommended position for the Frosty burner.

Here you can see the tip is positioned below the air entrance port.

I will trim the length of the lamp tube, since I reckon there is no need to attempt tuning the position deep inside the 6" pipe. 

Also not shown, I will add a lock nut to the lamp tube to ensure it doesn't move once tuned and a shutoff ball valve for convenience and saftey. 

I'm using a pneumatic hose coupler to connect to the Propane hose. Not sure that's a great idea. It doesn't leak at the moment, but I don't if the gas will have a corrosive effect on the o-ring over time.

Once I get it lit, I'll share pics of the flame as well tuned as I can get it and based on the comments I've read about what makes a good flame.

Cheers, 

Bob

 

[Latticino]

Try it out, but be sure to use gas rated fittings and pipe tape on your joints. No air quick connects.

[bcrimmins]

Thanks, @Latticino

I have the pipe tape covered. When you "gas rated", do you mean the quick connect? Or a different fitting? The rest are all just steel and brass.

[Irondragon Forge ClayWorks]

Have you seen this thread?

https://www.iforgeiron.com/topic/54645-using-the-name-on-the-forum/

 

[Latticino]

1 hour ago, bcrimmins said:

. When you "gas rated", do you mean the quick connect

Yes, and any valves or regulators 

[bcrimmins]

Roger that, on both counts.

Cheers

[Buzzkill]

Also, the reducer bushing issue has been discussed before.  I believe Frosty has said that it creates more turbulence if you use such a bushing.  In other words it may affect the performance of your burner compared to using the prescribed T.  One of the early designs of the T burner used a threaded lamp tube to do roughly what you are doing, but it still employed the drilled and tapped T of the correct sizes.  There was a reason Frosty abandoned that design, but I don't remember what it was at the moment.

[stevomiller]

If the reducer gives you trouble you “might” be able to cure it by removing from the TEE, and then mill/drill/grind/ream a nice V shaped lead in, or a taper and radius, to the ID that screws into the TEE. Blend the surfaces that lead from the TEE into the pipe nipple burner tube. Essentially like doing a ported head and manifold on an engine. 

[bcrimmins]

Hey guys, I think I've made some progress. The modified Frosty burner I showed in the previous post (with a cross and a lamp pipe) produced what I think is a much improved flame, i.e., almost all blue flame instead of the mostly yellow/orange flame and with a low roar instead of the whistle from the first iteration. It's also more compact. But it 'buffeted' rapidly... "pup pup... pup... pup pup... pup pup pup...."   I think this is what Buzzkill and stevomiller were warning me might be an issue with turbulence generated by the reducer.

I thought it about it a bit and instead of grinding/milling/drilling the thing, I decided to try smooth out the transition from the T through the reducer with some water putty. While I was at it, I all so smoothed out the threads leading into the T, since it seemed like the air flow coming into the T would need to travel across that 'washboard' texture. I also did the same for the flare reducer, eliminating all turbulence that could be caused by either the pipe-reducer transition, the threads at the exit hole and the internal concave profile of the reducer chamber. 

Here's what it looks like through the top of the T (cross).  I still need to sand the watter putty a bit more to get a nice glassy-smooth finish. 

In the picture below, it looks like the water putty is pretty thick at the threads of the T intake holes. It's actually less than a millimeter thick, but I'll sand that down to the top of the threads to ensure max air flow.

 

still need to sand the

Here's the nozzle. I already sanded it down pretty good.

And... the big reveal... here's the flame. I feel pretty good about it, but it's my first flame so I don't really know if it's very well "tuned". What do you guys think? Is it good? Is it good enough? In any case, THANK YOU for all your help. 

[Trevor84]

Out of curiosity did you try Frosty's actual design and it did not work?

I ask as I am about to build the one he's spec'd out but with the 1/2" dimensions due to my small forge. According to everything I've read, his specific design works pretty darn good with the only mod possibly needed is to trim the mig tip. 

In burners101 Mike has a really good description of how to judge your flame for air/fuel ratio by the colors and shape. 

Looks like you have a better flame then before. Congrats