Forges 101

[D.Rotblatt]

3 hours ago, Glenn said:

Anything that is lost can usually be found in the last place you look (grin)

Unless you live with my family....

[Mikey98118]

Dollar to value of small burners

Most--not all-- commercial burners costs too much to provide too little.

Most--not all--  smaller commercial burners don't reduce enough in costs as their sizes go down; this is fair, because most of them are hand built, and are harder to manufacture correctly in their smaller sizes.

An outstanding exception to this is Amal burners, making them a worthwhile choice for people who would rather skip out on small burner construction

[Mikey98118]

Ups; that is pounds, and would amount to just two cents shy of fifty bucks; still a good deal.

[G-son]

11 hours ago, Mikey98118 said:

Dollar to value of small burners

Was this perhaps supposed to go in the "Burners 101" rather than "Forges 101"? 

Anyway, as you say, a smaller burner may require more time to build to the required precision, material costs only go down a little (from using smaller/shorter pieces), and you still need to do the same number of machining operations, setting the pieces in the mill/lathe etc. the same number of times as when making a larger burner. As usual the big cost is the time spent, not the materials. 

[Frosty]

3 hours ago, G-son said:

Was this perhaps supposed to go in the "Burners 101" rather than "Forges 101"? 

It certainly could but we were answering and clarifying a question in regards to a fellow's forge and burner. The two topics are so interdependent separating them often leads to more confusion than useful answers. 

A person CAN make burners as stand alone tools but considering the time involved it's more economical to buy a torch. A forge without a burner is a strange container. Different purposes call for different forges and burners, some forges work better with one large burner, others with multiple smaller burners and others with multiple outlet burners.

It's hard to discuss one without the other. It's like discussing tires without discussing the vehicle.

Your point about the labor involved in relation to size is exactly right and if you don't have access to machine tools the difficulty is increased exponentially with reduced size.

Frosty The Lucky.

[Mikey98118]

You're both right, and this isn't the first time I goofed that way

A little extra care in making the burner opening on your forges, makes burners rapid to change out. What with different size forges, which encourage different size burners, we can end up with quite a variety to move around for odd purposes. Of course very few new builders would agree that this is a positive. But we were all beginners once; how many forges ago...?

[Mikey98118]

Avoid temptation

  Length versus diameter (0r width) matters a LOT in a naturally aspirated forge; less so with fan-blown burners. Too much length requires too many burners, eventually creating too much back pressure for natural aspiration to work properly. In short, extra long forges are the equivalent of driving a car with its emergency brake on. Fan blown burners are lest bothered by this problem, but are not immune to it.

[Mikey98118]

Gas system maintenance

Threaded parts seldom seal gas tight; especially when exposed to full cylinder pressures, in the case of most cylinder-mount propane torches. The common fix is to use gas rated Teflon tape, but such tape is meant for relatively low pressures encountered in household natural gas lines. So, Teflon tape is not likely to work well on lines without a pressure regulator installed. Even then, they must be turned in the right direction to avoid unraveling during installation, and the tape must be kept away from the last two pipe threads to avoid Teflon shreds from migrating into the gas line;  inevitably plugging up the gas jet.

    A surer method is to apply gas rated gasket sealant on the threads of the male connection (kept away from the last two threads on the fitting’s end). If you disassemble the fitting later, be sure to thoroughly clean all traces of the sealant from threads first thing, lest some end up inside the gas line. You can also employ gas rated thread sealant (AKA Thread-locker).

Always clean the gas system before assembly: Teflon shreds are not the only junk that can enter your gas system. Burrs from cutting, grinding, sanding and threading operations must be thoroughly cleaned from the work pieces, and all lines and hoses cleaned out with compressed air, to avoid debris from accumulating in the small gas orifice of a burner. Debris could have collected in the fuel hose from the gas cylinder, if you rent cylinders from an exchange system, from junk in the hose, if you leave it off for a long time. Insects and spiders are attracted to fuel hoses, because of their stench of fuel vapor. Propane can leave a buildup of tar and wax in a burner's gas orifices; especially from really poor quality fuel. The wrong kind of hose fuel will rot out over time; only use propane rated hose.

Pressure test the gas system before use: Use liquid detergent in water to pressure test all joints on any gas assembly, starting at the fuel cylinder, and checking every joint including those in the burner. Some burner designs can tolerate minor leaks in the gas jet parts, by drawing them into the mixing tube along with incoming air; other designs will backfire from the smallest gas leak.

Caution: Normally the gas pressure within a burner is a little less than line pressure, due to its open gas orifice. But a plugged orifice will allow full line pressure to accumulate in all parts; without a pressure regulator (such as with cylinder mount torches) that will reach full fuel cylinder pressure; this can be well over 150 PSI. The very small orifice sizes used in small air/fuel torches are given to clogging from impurities found in propane fuel. Keep a set of torch tip cleaners on hand to clean out clogged gas orifices immediately.

[Mikey98118]

Forge Exhaust flames

Exhaust flames from your forge can simply the result of fuel that hasn't combusted, as in the case of fuel gas pressure being tuned up way too high. The more common cause of yellow exhaust flames is a large secondary flame from a poorly designed or constructed burner, which cannot be completely combusted within the forge interior.

A dark very solid looking yellow to orange flame can be made from new refractory that is "cooking off" calcium; this will not abate until the process is complete.

Caution: Blue exhaust flames are a sign of a reducing forge atmosphere, which even a perfect burner will give off, if its air intakes are choked enough. Be aware that blue exhaust flames will be accompanied by carbon monoxide production.

[Mikey98118]

Merry Christmas to all

[671jungle]

On 12/21/2019 at 3:59 PM, Mikey98118 said:

Caution: Blue exhaust flames are a sign of a reducing forge atmosphere

Not to be confused with the neutrally tuned solid pale blue flame coming off the burner itself.

[Mikey98118]

Yes; the difference is that a neutral blue flame from a burner is a primary flame envelope (AKA flame front), while blue exhaust flame from the forge exit is  from sunburned carbon monoxide from a tertiary, flame envelope.

3 minutes ago, Mikey98118 said:

sunburned

I should have called that not combusted secondary products (carbon monoxide) of all three flame fronts (envelopes).

[Mikey98118]

Calcium exhaust flames

I have recently noticed that fairly opaque looking yellow to orange flame can be made from some kinds refractory that is probably "cooking off" calcium from its binding agent; this will not abate until the process is complete. As the flame turns from yellow to orange, it becomes more transparent, and may even seem to  sparkle in a manner reminiscent of fireworks, in one guy's photos; it looked like his  forge was running pretty hot at the time.

This doesn't preclude other colored flames, such as purple and blue from being present in the orange exhaust, but they are an indication of poor combustion performance, and must be ignored until the refractory finishes out-gassing. It is best to address one problem at a time.

[Another FrankenBurner]

I had posted a picture in the 3D printed thread which demonstrates this.  It shows fresh kast o lite cooking.  It is quite obviously different from the flame.  It goes away pretty quickly during the first full firing.

Here is a relink to that photo:

 

[Mikey98118]

Thanks for posting it here. Frosty first brought the group's attention to the probable reason, and I was 90% persuaded. But earlier this week a smith posted a series of photos that left no reasonable doubt in mind...

[Another FrankenBurner]

My experimental nozzle prototypes start their life as plaster of paris to avoid wasting refractory on total failures.  The plaster nozzles present the same brilliant orange display the first firing.  Somewhere in my readings, it was referred to as calcination.  

[Mikey98118]

Have you any thoughts on what refractory will end up best for casting flame retention nozzles, and ribbon burners?

[Another FrankenBurner]

I don't currently.  We have built 6 forges with cast in refractory retention nozzles with kast o lite.  Several of them have many hours of operation and show no problems.  No longer having a steel nozzle is a great thing.  Every time I used to start up my forge, I would hear little popping noises as the scale would pop off the always thinning stainless nozzle.  The refractory nozzle also gets the mix tube a little further back from the inner forge and conducts less heat to the mix tube.  

Kast o lite is chunky clunky but it works well.  It takes the heat and it is tough stuff.  Ribbon burners could be made out of it but it sure would be nice to have something finer for that work.  It took a bit of experimenting to get the kast o lite/water ratio as good as we can get it.  It is much drier than we started out.  It ends up smooth if in a form, even at the drier mixes.

I have been dabbling in high alumina ceramics and the bentonite/zircopax concoctions but not enough yet to have any conclusions.  If I could get either of them right, it would be nice.  My TIG welding torch has a pink high alumina ceramic nozzle which is thin walled, thermally stable, and seemingly indestructible.  I would like to figure that out.  

[Mikey98118]

On 12/29/2019 at 9:04 PM, Another FrankenBurner said:

My TIG welding torch has a pink high alumina ceramic nozzle which is thin walled, thermally stable, and seemingly indestructible.  I would like to figure that out.

I tried that out about twenty years back, and found that, when used as burner nozzles, they only lasted for seconds

[Another FrankenBurner]

Well that's good to know.  I don't want to use mig torch nozzles as retention nozzles.  I am trying to figure out how to fire a high alumina ceramic with the tools I have.

Ron Reil has a box of old prototype burners up in his loft which, of course, I had to dig through and investigate.  In this box was a copper burner that looks like a predecessor to the Hybrid burner.  It has a mig tip nozzle as a flame retention nozzle.  He said he could not recall who, but that someone had sent it to him years ago.  Based on the Nanomongo burner on his webpage, which he credited to you, I wondered if this mig nozzle burner was also something of yours.

[Mikey98118]

Yes; I sent him a Micro-mongo test burner made of copper pipe fittings. I recall still using rows of holes at that point.

[671jungle]

Made the cuts for the D forge.  It will be powered by a bottom mounted 3/4” burner. Maybe 2? 

[671jungle]

Guess I’m starting  with overkill and go for two burners. One port can always be plugged. This build has me all excited to see that “white heat” in a bigger space. I’ve always wanted to enter a kiln like room where everything is “whiteyellow” hot. Not in this lifetime . Also got some cool cut outs from the work. Maybe a wind chime of sorts?

[671jungle]

worked a bit more on the forge build.

Cut holes in the plate for extra support under stainless baking pan.

[Mikey98118]

Glad to see you positioned both burner portals toward the back of your forge.

Obtaining white heat (above 2700 F) in a small space requires hotter lame temperatures from a better burner design. added oxygen, or a hotter burning fuel than propane. Propylene in refillable cylinders (from a welding supply store), ends up no more expensive than burning propane, as the 1/3 additional fuel cost is offset by the 1/3 higher flame temperatures, allowing the burners to be run at lower fuel pressure. Otherwise, the burners must be turned up so much that the forge will have a huge exhaust flame.

As Another Frankenburner can attest, such temperatures usually require any flame retention nozzle to be made from refractory; #316 SS nozzles will end up dripping unto the forge floor at worst.

Great looking stand in the photos