I got this crazy idea last night. Yeah, this was after buying 100' of 3/8" A-36 last night.  I wanted to make a new forge that would allow me to turn my ribbon burner directionally as needed. 

In other words, I can have the full length of the burner down the length of whatever is being heated, or turned so only the smaller width of the burner heats only a small section.

I have metal sheet cut out 9" wide by 16" long for all 4 sides.  I plan to clean and weld those tonight.

This little model doesn't have the panels all correct, but it is a functional model.  The insides will be covered with insulator (Kaowool or similar) then coated with castable refractory and kiln wash.

The burner assembly will be built into a plate that is also insulated.  I know there will be some flame escape at the crack, but there shouldn't be any real chance of that doing harm.

Enjoy the musings of a guy who invents insanity at will.....

Happy forging!

The Toolshed - Rob

I'm not sure how much benefit there will be to that set up, but it looks functional.  I believe Frosty has mentioned in other threads that in a gas forge we are heating the interior surface which then radiates the heat back into the forge to heat up the stock.  Generally speaking you don't really want the flames to impinge on the stock directly.

If you go through with a full scale build let us know how it turns out.  Every once in a while someone's new idea changes the game.

1 hour ago, Buzzkill said:

I believe Frosty has mentioned in other threads that in a gas forge we are heating the interior surface which then radiates the heat back into the forge to heat up the stock.  Generally speaking you don't really want the flames to impinge on the stock directly.

With minor exceptions (some forges are deliberately designed to create a hot spot) that is correct. However, flame impingement is pretty unlikely with ribbon burners, because their flames are so short. I'm sure that someone somewhere could "push the envelope" enough to create a problem, but they would need to push real hard 

However, Frosty probably would advise Toolshed to pay more attention to his exhaust arrangement. Perhaps something smaller and longer might serve his purposes better. We must always watch out for a buildup of back-pressure in long narrow forges...

Uh HUH. Mike, note our new friend is making the common beginner's mistake of using the dimensions of his shell rather than the ID of the forge chamber. If we were to assume  a "basic" 2" of kaowool, + 3/8" of castable refractory and however much kiln wash he applies, call it insignificant we get 2.375" per lined inside wall, multiply x 2 = 4.75" Subtracted from the 9"x9" shell we get an inside that measures almost 1.9" x 1.9". Hmmmm,  maybe the thickness of the kiln wash IS significant.

I hope you have enough sheet steel to cut new shell walls Rob. Don't sweat this is a really common mistake, I think everybody makes it when they're breaking into the craft. No need to ask me how I know,  I'll have to make something up. Actually I kept that utter failure around till it finally disintegrated as a reminder. It never saw a flame.

Before you cut the shell, start with the chamber dimensions and work your way out.

About making your Multiple Outlet Burner (MOB, Ribbon describes the shape of the MOB. Yours MIGHT fall into the category called "Button burners.") Back on topic, mounting yours so you can turn it 90* is very doable but not the way you envision. 

If you try to make moving surfaces very close at all, they'll fuse together and stay where they fuse. Conversely you can't leave a gap or the burner will induce outside air and MOBs aren't so good with extra air. UNLESS you like the idea of tuning it every time you turn it?

My first okay NARB forge had flanges around the output side of the burner block and it just rested on the top of the shell. It wasn't really workable because the T inducer meant it had to either balance well or be screwed / welded to the shell. 

The current NARB forge burners are welded to the shell. I WISH I could tilt them and direct the flame back towards the back wall to make a hotter zone but it is what it is now. It doesn't get as hot as an equal volume forge driven by equal size single outlet T burners but it'll weld if you do it right and the interior holds a very even heat.

When I was experimenting with burner blocks and outlets I tried a number of things I wasn't equipped to produce as a finished burner. Some were doable and not prohibitively difficult. Fanning the flames out within reason worked nicely. If you envision your MOB crossways in the chamber, looking at the flames from the end you'd see the center flames 90 down grading to maybe 60 out at the ends. Hold your hand up and spread your fingers, sort of fan shape. Make sense?

Angling them towards the center was an experiment I hadn't thought out first. Yeah, I turned 23 small flames into ONE big soft one that wasn't as effective as a 3/4 T.

Now I'm starting to ramble between points, more later.

Frosty The Lucky.

 

On 6/20/2025 at 2:16 PM, Frosty said:

About making your Multiple Outlet Burner (MOB, Ribbon describes the shape of the MOB. Yours MIGHT fall into the category called "Button burners.")

Okay, that makes two terms that got by me 

MOB makes sense, but what is a button burner, Frosty?

We talked about so much stuff while we were discussing these things I'm sure lots of stuff slipped past us both. A "Button" burner is or was the industry name for a round MOB. Depending on the manufacturer, it seems many had to make up "special" names for their products but button seemed to be pretty prevalent. 

Frosty The Lucky.

Thanks, Frosty.

It is good to have something new to look up 

Are you still messing with MOBs?

I haven't in a couple few years. I never did get far with a ring version. The more I thought about it the more I started realizing it was one of those, "Sounds good but what for?" Ideas.

One of the reasons I hang out here is to catch the occasional new idea, tool, etc. That and passing on what I've learned to newbies. But NEW is good, I like new. 

Frosty The Lucky.

2 hours ago, Frosty said:

The more I thought about it the more I started realizing it was one of those, "Sounds good but what for?" Ideas.

I try not to let "the practical" catch up to me and spoil the fun; at least not until the dogs get to run wild for a while 

MOBs are the next place I'm going to; it may take two or three more years before I have time to do more than think ahead on this subject, but it fits nicely into advance torch work, which is what I have wanted to investigate for years. So what do multiple flame burner heads have to do with torch brazing, and welding? The more effectively the work can be preheated with air-fuel burner systems, the less heating needs to be done with oxy-fuel torches; therefore, the smaller those torches can be, and the less hideously expensive oxygen they consume.

A large percentage of my idea development is on paper and little journeys of the imagination. Imagination and blue sky speculation usually lead the way, then I attack the plausible with pencil and paper. II can still think of a number of useful things to do with a ring MOB, just none at a scale I work. I've seen oxy nat gas ring burners doing as you say pre-heating stock before going into the forge ovens.

Frosty The Lucky.

 

20 hours ago, Frosty said:

I've seen oxy nat gas ring burners doing as you say pre-heating stock before going into the forge ovens.

My goal is just the opposite of your example. I want to use forges, to preheat parts for oxy-fuel brazing, to drastically reduce oxygen consumption.

The bottom line with oxy-fuel heating, is scale, because the bottom line of oxygen enrichment for gas heating equipment is amount; the more you use the cheaper it gets. But the price break only begins with huge refrigerated cylinders, where the liquid oxygen is cooled enough by use that thick walls aren't needed to keep it liquefied by compression. Small businesses and hobbyists, are limited to compression cylinders, with nice high prices, on top of cylinder rental charges. For industrial consumers, oxygen is so cheap that fuel price, is the deciding factor; for the little guy, the opposite is true. So, our thinking must be opposed to that of industry; for them it has always been "bigger is better." For us it should always be "less is more."

 

I wasn't clear, large oxy methane ring burners preheat stock going into industrial mill furnaces after which they go to shears and the roll mills. I'm not going to do the math but a 4'dia. x 6' round steel billet rolls out to a couple few miles of 1/4 rnd. Heading into the furnace they've typically run through a couple dozen large ring configured oxy methane burners. The real heat issue in commercial rolling mills is having to keep the stock cool enough. The run is almost constantly being sprayed with water to control it's temperature which descales it nicely before it's pressed into the run by the rolls.

They're kind of iron works that gets both methane and oxy by the trainload and tap tanker cars directly.

Scale using my oxy propane torch is a matter of improper flame adjustment or technique. Sure you can develop more heat by over pressuring the oxy but the fuel being burned in that case is the carbon and iron in the steel.

Steel exposed to open air oxidizes. Period. The hotter it is the faster the chemical reaction is basic chemistry so steel heated much above low red oxidizes while you watch forming scale. Which is different than red rust but I'm not looking up the formula, I'm sure someone will save me the effort.

Frosty The Lucky.

Well, we have both drifted pretty far afield; I enjoyed quite a bit  

That was actually a great thread hijack.  I did kinda take into account what the FINISHED forge would be inside.  I had wanted 2" kaowool (down to about 5" since 9"-4"=5")and then various thicknesses of various refractories reducing to about 4" square inside.  I was hoping to end up with a chamber with movable end caps so I could do longer sections.

This is all moot at this point because I don't want something that large taking up space in my shop.