Burners 101

[Jbradshaw]

Mikey,

 I started pricing out the parts to build a vortex burner a couple of weeks ago. Ultimately I decided that I would skip it for now since I was basically looking to build one just to build it (my 3/4" Mikey burner heats my forge just fine but I like to tinker). Now you go and start talking about them again and I may have to jump into a build (I'm currently waiting for the refractory to dry on some ribbon burners following Frosty's design, one of which I'm going to try to power with a Mikey burner instead because why not).

I will have to check to see if the tubing I have leftover from building my previous Mikey burner will work for any of the parts on the Vortex burner.

John,

That diagram is very helpful. I was having a hard time visualizing what was going on with the aluminum block.

[Mikey98118]

Nice drawing, John!

It's interesting that you chose to show the sausage stuffing tube, which is being used for a funnel, inside of the mixing tube. In fact, I mount them inside or outside, depending strictly on convenience; this is because of the tube wall's thinness and the strong mixture feed inside the mixing tube with these particular burners. 

The longer you wait the more you'll have to work with. John, on the other hand, feels differently

[Frosty]

Oh this is getting better all the time!

Frosty The Lucky.

[John in Oly, WA]

Thanks Mikey. Glad I could help JBradshaw. I'm just used to overlapping things according to the direction of flow - like downspouts on a house. We'll see what the actually inside/outside diameter is and the SS tube/pipe diameters available to see where it ends up.

[Mikey98118]

Frosty,

Squrill cage fans, which are a total no-no on These burners, could provide enough push to possibly combine well with multiple flame heads. That might just enable people who like ribbon burners to change their flames enough to get rid of any dragon's breath?

[Mikey98118]

On 2/6/2018 at 1:46 PM, John in Oly, WA said:

I'm just used to overlapping things according to the direction of flow - like downspouts on a house.

That is a very good point, for something that is going to push fuel gas and air past a joint.

I am used to using sealant and having my druthers, but common sense should always be the first concern in burner construction.

[Mikey98118]

On 2/6/2018 at 1:46 PM, John in Oly, WA said:

We'll see what the actually inside/outside diameter is and the SS tube/pipe diameters available to see where it ends up.

I like to buy from Onlinemetals.com because they have a good variety of sizes and materials; If I can't find a convenient diameter in one material, it will be available in another.

[John in Oly, WA]

@Mikey98118 I was looking at OnlineMetals. They have 304 and 316 SS. Looks like they have a good selection of thick wall SS tube. Be nice to find some 310S or 330 for the nozzle. Also got notification that the sausage stuffer tube had been delivered, so I'll post the measurements and you can let me know what will work for the other parts.

[Howling dog forge]

Are you aware of the rather high expansion coefficient of SST?  work hardens with heat cycles as well. Not saying this won't work or  even that there is a better alternative , just the first thought that comes to my mind when I think about turning stainless steel bright red.

 

[John in Oly, WA]

Not real familiar with all the characteristics of stainless. I know it doesn't machine well - kind of (there's a word for it) smears. My metallurgical education is ongoing. But I think it's a matter of what is workable in a cost/benefit scenario. Mild steel would probably scale away or melt faster. Something like titanium I know nothing about as to availability, or workability, but I think it handles high temps well. 310S or 330 stainless is supposed to handle high heat cycling better than the more common 304 or 316, but it is hard to find. So, 316 with the understanding that the flame nozzle is somewhat sacrificial.

[Mikey98118]

16 hours ago, Howling dog forge said:

Are you aware of the rather high expansion coefficient of SST?  work hardens with heat cycles as well. Not saying this won't work or  even that there is a better alternative , just the first thought that comes to my mind when I think about turning stainless steel bright red.

I'm a big fan of stainless steel burner parts; but only where they are the practical choice. Up to 3/4" burner size, the added cost is minimal; beyond that, I would recommend mild steel for everything except the flame nozzle. Nor would I hesitate to switch out stainless in order to get a closer fit in part matchups, if that were how the cards fell.

I go into the problem of work hardening, and other handling headaches of stainless steel in instructions later on, and more than agree with your caution in the matter...but SS parts are pretty, and they stay that way. Extra work building your shiny new burners are soon forgotten when others see them with a predatory gleam in their eyes; such is life

BUT, outside of the flame nozzle, what material we choose is strictly a personal choice.

So, thank you for bringing it up.

[Mikey98118]

John,

You do realize that this SST (sausage stuffing tube) only has an inside diameter 1/16" larger than the standard 5/8" inside diameter used in 1/2" size burners, don't you?

I am also having trouble getting the really large SST I wanted to use for my version of an SST based 3/4" Vortex burner. We can still use the wine funnel version of this burner, or we can build a 1/2" size SST version; your choice.

[John in Oly, WA]

Yes, got mine yesterday and it seemed a bit small. I'd like to stay on course with the 3/4" build. So, we're looking for something with an inside diameter around 7/8" and that will be a 3/4" burner? If we could find a 1" sausage stuffer tube, would that work?

[Mikey98118]

LEM Products makes a 1" outside diameter SST; that actually ends up about .060" larger than the standard pipe size for a 3/4" burner. The LEM SST is top quality too; unlike the three Smokehouse products that I have from them so far. The 1" SST is a little short on Funnel length, but we will make up for that by using a 3/4" thick aluminum fan mounting plate, which we will bevel to--in effect--lengthen the funnel section and increase the diameter of the fan opening. Fair enough? This is no burden to me, since the book demands all three methods of making a 3/4' Vortex burner.
 

[John in Oly, WA]

I was looking at the LEM and the funnel looked a bit short. I couldn't find a sausage stuffer tube with a longer funnel, so just to confuse things a bit more, I then started looking at stainless concentric reducers.

Then began wondering about the ratio from one end to the other. I think I remember you saying 3:1 max. But is that ratio of diameters, which comes out to be .75" to 2.25" -  or areas, which comes out to .75" to 1.3".

I found concentric reducers with I.D.s of Large End 2.157" to Small End .884" and thought about just welding them to a thick wall mixing tube.

Ah, all the possible variations! Lets go with the LEM SST and the 3/4" aluminum block and see how it goes.

[John in Oly, WA]

I can play around with reducers later.

[Mikey98118]

Don't forget that the actual inside diameter of schedule #40 3/4" pipe is 7/8"  another bit ofwriggle room can be provided by going for a slightly larger mixing tube. And yes, high-quality reducers, like stainless steel types, are perfectly acceptable air openings.

Don't forget that the actual inside diameter of schedule #40 3/4" pipe is 7/8"  another bit of wriggle room can be provided by going for a slightly larger mixing tube. And yes, high-quality reducers, like stainless steel types, are perfectly acceptable air openings. the three to one maximum is blade diameter to mixing tube inside diameter, so if the large opening of the reducer is over three to one, just use a slightly smaller fan. Perfect matchups are nice, but we do what we must to live with our part choices

[John in Oly, WA]

I found the LEM 1" SST with the 2" base here for same price - https://shop.jayssportinggoods.com/lem-products-inc/stuff-tube-ss-2in-base-od-1in--271113   It has a little more flare at the base end.

The stainless reducer I found, the small end is .884", so that would fit the schedule 40 7/8" dia.

 

[Mikey98118]

 

this is just as good a construction path as any, and I can assure you that it works out well for flow characteristics and least possible backpressure at the funnel to fan interface. I used a similar part to build my first "V"  burner. Once you have the mixing tube, buy a long enough length of threaded rod to extend comfortably beyond both reducer and mixing tube with room to spare for nuts, a large washer for the tube end, and a drilled plate for the reducer end. Then clamp all of the parts together for silver brazing. You will have to use at least 50% silver filler and flux meant for brazing on stainless steel.

Use a square to ensure that both part ends are at true right angles in order to keep their join in line during brazing.

Brazing S.S. Funnels to Couplers and Mixing Tubes

 

Aside from burners built from sausage stuffer tubes (and a very few other exceptions), a burner’s funnel section must be joined to its mixing tube by cutting back its small end, and adding a coupling tube, into which a mixing tube will rest.

    With the exceptions of one 1/4” and one 3/8” burner built from sausage stuffing tubes, no funnel on a Vortex burner is permanently affixed to the burner’s mixing tube; not even when the funnel’s stem and mixing tube are a close enough match to make a brazed joint between them tempting.

    The main reason for employing coupling tubes is to provide a greater variety of available burner sizes; it also gives easy access to the gas jet for centering during construction, and occasional re-centering after cleaning. Propane comes in widely varying quality from different sources, but even the best of it isn’t perfectly clean (we aren’t talking about triple refined lighter butane here).

    The waxes and tars that all commercial propane contains are capable of plugging small capillary tubes, or even the smaller MIG contact tips, thus ruining burner performance, while rapidly increasing pressures on gas hose and gas fittings to full cylinder pressure, unless a proper regulator—not just a needle valve—is employed. Poor quality “bargain” propane can form plugging tar balls quite rapidly.

    It then becomes necessary to shut down and clean the burner by poking the tar ball out of its gas jet with a set of torch tip cleaners (or piano wire for very small orifices), and blowing it back out through the larger diameter gas tube with air pressure; canned air is fine for this if you don’t own a compressor.

    You are being shown how available funnels can be attached to available tubing products as a convenience; nothing stops you from producing your own turned or spun funnels, should you have a lathe handy. Unfortunately, even with SSTs, working with what’s on the market restricts possible selections, and so the occasions when funnels can be directly screwed onto, or trapped within, mixing tubes are limited.

    Fortunately, “coupling tube” connectors can be generally employed to ease burner construction. A short section, made out of the same tubing used as a spacer ring between the burner’s flame nozzle and mixing tube, can be silver brazed directly onto the funnel after threaded holes are placed in its forward end, and its joint face is beveled to closely match the funnel’s angle.

    This coupling tube replaces the original funnel stem (which is cut away before brazing, and any excess sheet metal protruding into the mixing tube is ground away after brazing). Subsequently, funnel and coupler are secured onto the mixing tube with socket head Allen screws.

   So, how short is short enough? The portion of coupling tube that extends beyond the funnel should be at least twice as long as the mixing tube diameter on miniature burners, and one and a half times the diameter of 1” and larger burners.

    You need to keep the coupling tube short enough to easily reach well into the gas jet at the gas tube’s end with torch tip cleaners, for possible removal of tar balls. Standard torch tip cleaner sets are a full two inches long. There are also extra-long torch tip cleaner sets with more than twice that length. If you don’t construct a gas jet centering rod you will also need clearance for needle nose pliers, (centering rods are discussed further on).

Note: Not only does tubing come with plus/minus tolerances (between 0.002” and 0.005” on small tubing diameters), but it isn’t perfectly round, although it’s much more concentric than pipe.

    When you are power sanding parts to create a close fit, don’t forget to rotate them while checking how well they slip together. Before securing the coupling tube on the mixing tube with Allen screws, rotate both tubes to assure a tight fit; twist to loosen them before disassembly.

    Remember to completely remove internal burrs and chase the screw threads as many times as required to ensure a smooth fit between coupling ring and mixing tube; a round file wrapped in sandpaper can be a great help in removing the internal burrs and deformations made by a threading tap.

    Some funnel stems will fit closely enough on smaller tube sizes (up to 3/8” burners) to slip over the outside, or into the opening of D.O.M and stainless steel tubing. Pan-head screws are good enough to attach a funnel stem to the outside of a mixing tube. Otherwise, a separate tightening fixture is called for; a locking collar. After cutting a thin slot into the mixing tube or onto a funnel stem’s end (not quite as deep as the collar is wide), a simple inexpensive drill bit collar can be used to squeeze the slit tubing section tight  around the funnel stem inside it. Stop collars are commonly found in sizes meant for 1/8”, 3/16”, 1/4”, 5/16”, 3/8”, 7/16”, and 1/2” diameter drill bits. But drill stops are also available in size differences given in sixty-fourths of an inch;

Mandrel collars are very similar to drill stops, and the same part might be found under either category in a large hardware store.   

    Two Allen screws can be added at one-third distance from the first screw, and from each other, to increase the tightening and centering effectiveness over that of a single screw. The collars are available in a variety of single piece sizes at most hardware stores and in cheap sets through amazon.com and eBay. By drilling threaded holes for three equally spaced Allen screws into at least 1/8” thick wall tube (thicker is better), you can create your own collar in a convenient length for any tube diameter. drilled out round bar or hex stock can be even handier if your mixing tube’s outside diameter is a hard size to closely match. Worm screw hose clamps can only be used when the funnel is slipped inside a mixing tube, and are not recommended in any case.

[Mikey98118]

When you choose to attach a reducer directly onto a mixing tube, it becomes important to ensure a perfect fit.; Otherwise the joint must be power sanded into a smooth transition; this isn't only needed for good mixture flow. You must build and use a centering hod to ensure that the gas jet is soldered or brazed dead center in the middle of the mixing tube during construction. Afterward, the rod will be used to ensure the jet stays centered during maintenance. The rod must move smoothly past the joint, to work properly.

[Mikey98118]

 

that should read "centering rod"

[Mikey98118]

So, which is better? Handy and Harmons' white stainless steel flux, or one of the black fluxes? I've used both kinds; they are both good products, but I prefer the white flux for sweating, and the flack flux for keeping the brazing area exact.

[Mikey98118]

So, here were are, once again with a whole lot of needed information stuck on the previous page, and left unavailable because we can't back up to view it. Any ideas???

[DavidF]

Mikey, I have the same issue. Navigate back to page 38 and then refresh your browser in the URL address line. It is a bug and the platform (whoever develops the forum software) will most likely need to provide an update or patch. I also am a member of bladesmithsforum.com and it looks like they use the same platform, but they do not have this refresh/navigation issue. I will look and see if there is a way to report the issue, but I wanted to give you a temporary workaround. Let me know if you need more information on the instructions.

Update: I posted a screen grab with the refresh button circled on an iPad/Safari platform. So in this example, if the last page is page 39, you can go back to page 38, but then when it doesn’t load, you just click the refresh button in the browser. That will get you back to page 38 as a work around.

Update 2: I sent a message to the administrators describing the issue and the workaround. Hopefully, it is something they have already addressed and they can quickly patch it.

[Mikey98118]

Thanks, Mike.