Need help with tuning Frosty T-burner

[Erik F.]

Hi everyone,

Newbie here in Portland, Oregon. I just finished building my first forge and need some advice with tuning my Frosty T-burner. Here are the specs:

 

Forge: Wayne Coe-style Freon forge, built exact to his instructions -- 1-2" Inswool, Kast-O-Lite refractory, Plistix

Burner: Frosty T-burner, 3/4" nipple, 0.035 Tweco MIG contact tip, no flare (tried to build one into the refractory, but my guess is it's probably a little too wide)

Other stuff: 1/4-turn ball valve at the burner, 3/8" propane hose, 0-30psi regulator

 

The pics are taken with about 5psi of pressure. The burner nipple is situated so that it's barely inside the tank (and prob. 1.5" deep to the refractory).

 

I was hoping I could get some advice about the flame -- shape, color, etc.. Please forgive my ignorance. I'm assuming I need to trim back the MIG tip a little -- it seems like that's the first recommendation from most of the posts I've read -- but I wanted to check with the gurus first before I went and did that.

Forgive me if the pictures aren't helpful, or if others would be better. I'm happy to retake if necessary.

 

Many thanks in advance,
Erik

[Latticino]

I'm sure some of the flame experts will be along to discuss in more detail, but it looks fine to me.  You are getting a little burn off from your refractory, which is normal until it bakes completely after several firings up to temperature.  Just don't get ahead of yourself and fire things up too fast.  You need to thoroughly dry it out, then bake it slowly to avoid cracks.

[Irondragon Forge ClayWorks]

You have built a good looking forge there. I agree with Latticino and take any steps recommended one step at a time and take notes.

[Frosty]

Nice job Erik, that's a pretty good looking flame for only 5psi. How's it burn at 10psi? 

I don't pay much attention to what psi someone else's burner runs, there are too many variables for it to mean very much as a useful metric. 

The flame looks a bit rich, I'd start trimming the jet back 1/32" at a time and carefully debur the hole with a torch tip file. Be gentle or the file will deform or enlarge the jet. 

What does it sound like? No video or audio please L'll take your ear's word for it. It should really roar, all but scream. Yelled conversation anywhere in my shop with one running is the norm.

Two things about the build: Your burner is aimed almost directly into the corner between floor and wall, this causes unnecessary back pressure, aimed up or down a little will make it happier.

Secondly, If you move your 1/4 turn ball valve to the outlet side of your regulator it will take some of the weight off the burner and depressurize the hose when you shut it off. Keeping pressure on the output side of the reg while it leaks off isn't particularly harmful but it's not a good thing either. That's for a little later though, no rush. 

Frosty The Lucky.

[Erik F.]

Wow. Many thanks to the three of you for such a quick response. Much obliged!

 I’ll be sure to go slow and limit it to one variable at a time. 
 

Frosty:

1. I’d say the burner is loud but I wouldn’t call it screaming. Granted, my garage door is open, so maybe that decreases the noise level, but still, I wouldn’t have a hard time holding a conversation. What would the sound indicate about the burner?

2. The flame seemed about the same to me at 10psi. If it would be useful, I’d be happy to post some pics at different pressures. 

3. I’ll work on orienting the burner away from the corner. I meant for it to come out more horizontally, but my burner port is a little off. But I think I have room to play with. 
 

4. I’ll see if I can put the shutoff valve on the regulator side. I had planned on doing that, but the all-in-one regulator/hose/pressure meter doesn’t seem to let me. The junction b/t the hose and meter just spins, and the junction b/t the meter and regulator doesn’t budge. Maybe I just need to twist harder (b/t meter and regulator)? But I was concerned about breaking something. 
 

5. One more question: I have a gap between my burner and my burner sleeve. I just stuffed some Inswool in the gap to reduce the chimney effect. Is this okay long-term, or do I need to come up with a better solution?

 

Again, many, many thanks to all you folks. Your generosity with your knowledge and advice is so appreciated. 
 

Erik

[Mikey98118]

This burner will only heat up more from the chimney effect, by forcing all the hot gases to exit via the burner. Also, this kind of burner probably needs some secondary air to burn completely; maybe not, but probably yes.

[Erik F.]

41 minutes ago, Mikey98118 said:

This burner will only heat up more from the chimney effect, by forcing all the hot gases to exit via the burner. Also, this kind of burner probably needs some secondary air to burn completely; maybe not, but probably yes.

My apologies, Mike. I think I’m using the term “chimney effect” incorrectly. (I realize now that term means when residual heat moves up through the burner tube after shutdown?). What I was trying to refer to was the way in which hot air and small flames exit out through the gap b/t the burner and the burner sleeve, while the burner is running normally. Is this okay to have? The flame seemed better when the gap was plugged. 

[Frosty]

No need to apologize Erik, Mike I and a number of us are used to folk new at the craft misusing terms usually in worse ways sometimes downright comically. We often see folks call flame being forced out through the annulus between burner and mounting tube the chimney effect. What you're seeing is an effect of the back pressure I was referring to.  Chimney effect is convection drawing forge temp gasses up through vertical burner tubes like smoke up a . . . chimney.

Mike was saying that once the back pressure issue (assuming that is the cause) is corrected then the flame from the burner will produce a low pressure zone in the gap drawing more air into the forge chamber. The same induction action as drives the burner. 

If possible I like to get a burner tuned to a slightly rich combustion ratio, it isn't as hot as possible but it prevents scaling in the fire. 

Regardless if it's a correctly tuned burner or the right amount of secondary combustion air induced in through the gap between mount and burner it makes for a HOT forge.

If your regulator and hose are set up that way don't change it, especially if you think you'll have to force it. Those darned hoses are usually the most expensive single component between the tank and burner. If the weight throws the jet's position off, you'll notice, ask me what's wrong and we'll correct it then. 

Frosty The Lucky.

 

[Erik F.]

Again, many thanks to you guys - your help is much appreciated. I'll tinker with the forge tomorrow and let you know if things aren't correctable.

-Erik

[Latticino]

8 hours ago, Erik F. said:

What I was trying to refer to was the way in which hot air and small flames exit out through the gap b/t the burner and the burner sleeve, while the burner is running normally. Is this okay to have? The flame seemed better when the gap was plugged

Good, then you should leave it plugged.  I would also  hold off on making any changes to the burner until the refractory is thoroughly baked.  The flame can be a little misleading until that is finished.  Once done inspection of the quantity of "dragon's breath" exiting the doorway in dim lighting will give you an idea of whether you are overly reducing.  As Frosty indicated, a little reduction is generally a good thing.

[Frosty]

Three's one more thing I usually to say but forgot.  "Change ONE thing at a time, test observe and take notes." 

If you change more than one thing at a time the effects become exponential and you won't know what did what making a good result a lucky mystery. 

For example, Mike and I use much different techniques to tune a burner. The basic effect is the same they alter the amount of combustion air induced and so the burn ratio. Try mixing the techniques and there's almost no telling what'll happen next, a burner can go from really close to won't burn at all. 

Frosty The Lucky.

[Erik F.]

Will do. Thanks, guys.

[Erik F.]

Well, dang. This is frustrating.

I was testing the forge this afternoon. It had been going for a couple of minutes when I noticed that my burner holder looked funny. It was melting! There was a nice little puddle of molten stuff on the floor of the forge.

The holder/sleeve is made out of a steel electrical conduit connector fixed to the tank with conduit reducing washers and conduit lock rings (idea taken from Zoeller "simple atmospheric gas forge" design). In retrospect, he used a 1-1/2" iron nipple for the sleeve -- I misread it and used an actual steel conduit connector, which is flimsier. At the risk of sounding stupid, was this the problem?

*sigh* Now I have to figure out what to do. I did it this way because I don't have access to a welder. I'll now have to figure out some way to fix the burner to the tank. If anyone has any ideas, I'd be grateful.

Pics of the gap b/t the burner and sleeve right in the beginning, followed by the aftermath.

 

Right after firing up, before stuffing some Inswool in the gap:

 

Aftermath:

 

Flame before it melted

[ThomasPowers]

Don't think that fixture is steel; test one with a magnet!   (I'd guess something like zamac; aha "Conduit fittings for general purpose uses are commonly made from die-cast zinc.")

[Erik F.]

Son of a gun. You’re right. It’s advertised as “zinc plated steel“ but when I look in the fine print, the actual connector is zinc, and only the screws are zinc-plated steel. 
 

That’s so embarrassing. I’m an idiot. 

[Panik]

57 minutes ago, Erik F. said:

*sigh* Now I have to figure out what to do. I did it this way because I don't have access to a welder. I'll now have to figure out some way to fix the burner to the tank. If anyone has any ideas, I'd be grateful.

A suggestion for a fix..... If you look in the plumbing section of your local big box hardware store they sell brass termination flanges. I used one as the port/holder for the burner going into my forge. It's a little pricey at about $20.00, but it makes for easy installation. You just have to drill and tap holes for the bolts that use to hold the burner in alignment.

.... And don't be embarrassed. I bought all of the nuts and bolts to hold my forge together before I realized that zinc plating is somewhere the opposite of a good idea.

[Irondragon Forge ClayWorks]

You can get a short piece of automotive exhaust pipe that your burner will fit in from any muffler shop. They usually have a cut off bin. Cut one end down (make 4 slots) and bend them out to make a flange that you bolt to the forge body with self tapping bolts.

[Frosty]

Another option is to buy a "Floor flange" and close nipple to make the sleeve to mount the burner. A black iron pipe nipple drills and taps easily and there's enough wall thickness for good strong threads. There should be enough for two sets of screws one above the other so you can aim the burner precisely. 

The floor flange will screw, nut and bolt or pop rivet to the forge shell easily. 

Either take your burner with you or if you're sure what size pipe you made it from pick a piece say 3-4" long to use as a gauge to decide which close nipple will work best for your mounting sleeve, then get a floor flange to match. 

Did you see any blue green flame and white lacy smoke? Zinc produces toxic fumes when it burns, it's a pretty color but it's B A D for you. 

Frosty The Lucky.

[Erik F.]

You guys are awesome -- thanks for the ideas! I rigged something up to hold the burner this afternoon, but I think I need to beef it up with one of your ideas. Looks like it'll be back to the store for more stuff - I think they know my face by now.

Frosty, I may have seen a trace of green flame right towards the end. Fortunately, it was only for a moment, right before shutdown. I'm counting my lucky stars. Very humbling....

Once again, thanks for the help.

-Erik

[ThomasPowers]

I've taken a piece of pipe cut it down the sides about 2" in a "+" pattern and heated and bent out the straps and formed them to fit the forge body. Drilled and riveted them with 20 penny nails, (I have a bucket of used ones I saved for riveting jobs)  Done BEFORE lining the forge body of course!  (The hole was made using a cheap hole saw sourced used at the fleamarket. The body was a He party balloon tank. Part of a "how cheap can I build a forge without using a welder?" experiment. I guess it's cheating that I was given kaowool at a scrapyard from furnace lagging...)

[Frosty]

A little out of tune flame is nothing to worry about at shut down. 

Frosty The Lucky.

[Erik F.]

Okay, I finally got a new burner sleeve up and running! I went with the floor flange and short nipple - thanks so much for the suggestions. 
 

I just fired her up. Pics attached. Again, it’s a 3/4” T-burner with nothing on the tip (no thread protector, coupler, etc.). Tip is positioned *just* inside the shell of the forge. Pics were taken at 5 PSI. 
 

After a few minutes, I started getting some white smoke coming out of the burner sleeve. I shut it down out of precaution. The burner sleeve floor flange and nipple were both galvanized, but the nipple sat in vinegar overnight and the flange in vinegar for 2+ days. I’m assuming (hoping) the smoke isn’t burning galv??? I didn’t see any blue or green flames. There’s a small air gap in my burner sleeve, b/t the sleeve and burner, if maybe that helps with diagnosing the issue. The sleeve got some WD-40 after the vinegar bath, too. 
 

Once again, many thanks for any advice. 
-Erik

[Irondragon Forge ClayWorks]

I'd say it's WD40 residue burning off.

[Erik F.]

20 hours ago, Irondragon Forge & Clay said:

I'd say it's WD40 residue burning off.

Thanks!

[Frosty]

It's definitely smoke but it's NOT zinc oxide smoke. Zinc oxide smoke is unmistakably distinct, it forms lace like or feathery floating "structures." If you took some of the well defined swirls in the pictured smoke and wove them together in shapes that maintained their shape as they drifted you'd have a fair mental image. 

Once you see zinc smoke you will never mistake it again. Do NOT think you HAVE TO SEE THE SMOKE to be exposed to zinc oxide fumes. Keep galvy anything away from HOTNESS around your forge. Better safe than sorry.

A trick I've found to be particularly effective preserving burner output / nozzles if giving them a dip in a dilute refractory, Plistex would be excellent but I've had good results with bentonite mixed to a latex consistency. Dip, let it dry and fire gently the first time and it provides a layer that doesn't allow oxygen contact with the burner so it doesn't burn up.

Frosty The Lucky.