Mikey98118

You have it right; a 3/4" Mikey burner is on the large size; fortunately, these burners have long turndown ranges. You have a guide plan so far. Remember that vinegar in water is the easy way to get rid of zinc coatings. That should read "...good guide plan..."

You can turn down the gas pressure on a 1/2 " T burner to serve, but stuffing a half brick in there is going to make it pretty hard to contain the flame in the forge.

8" is about the right diameter for a #10 tin can, as for instance a coffee-can forge or casting furnace.

All good info; the best kind

So, if we want the smaller orifice sizes, drilling your own hole in half-hard brass is the surest way, followed by needle tubing as the next best method. MIG tips are a long way third for coming up with orifices under .030" consistently.

I find all of the work going on with ribbon burners to be very impressive; I just don't want to disappear down that rabbit hole myself

That depends on the manufacturing source; those smaller orifice sizes are from foreign sources, and you will be tossing dice about actual orifice sizes. Older tips, including foreign, were designed to work on American made welding wire, and will run between 030" and .031" inside diameter. Newer foreign tips are made to work on foreign welding wire. So, to stand a chance of getting the smaller diameters, you have to choose millimeter threaded tips, and it is still a game of chance; been there done that.

.030" is the smallest hole size available in a MIG contact tip; it is usually installed on a 1/2" size burner. If that is what you plan to build, and plan to drill your own gas orifice .028 would be a better size for your drill bit. That would take a #70 bit.

How large a ribbon burner will heat 350 cubic inches of forge interior to yellow heat is going to need to be examined by someone who is into them. This is not a challenge, but an invitation. People will want the answer.

Input flames and forge atmosphere One 3/4” naturally aspirated burner, which is capable of making a neutral flame, will heat 350 cubic inches of open interior volume to welding temperature in a properly insulated forge (2” thick layer of ceramic fiber or the equivalent insulation in some other form). Add an additional 70 cubic inches for a burner capable of making a neutral flame in a single flame envelope (no secondary flame). Such a flame from a burner with an entrance port set up to control secondary air from being induced into the forge by its flame, and you can add another 35 cubic inches, for a total of 455 cubic inches. Addition of a sealing coating and heat reflective coating will raise forge temperature still further and allow lower fuel gas pressure to be used to gain yellow heat. When looking at the flame from a really hot burner—in a cold forge—It will look much as it does out in the open air, but within moments it will lengthen and become smoother in outline, as the forge starts to superheat; it will also lighten in hue to blue-white. There will be very little to no secondary flame within the forge, even while it is cold; lesser burners will make more complicated flame envelopes, but this is the ideal. You need to remember that there are at least two different flames going on within the average gas forge; the flame being input by the burner, and the possible output flame leaving the forge via the exhaust opening. When smiths discuss terms like dragon's breath it is the exhaust flame they are speaking of, which is a very different animal than the incoming flames from a burner. Not that both flames aren't equally important, but they need to be treated separately for clarity. So, if we are speaking about the burner flame, straight blue from a total primary combustion envelope is desirable, but many older burner designs have a white inner flame ahead of a blue secondary flame, followed by a darker larger and less substantial appearing tertiary flame of "secondary combustion"; but by that I refer to the combustion of byproducts of the primary combustion, which is something of a fiction in this case, for the white inner flame IS actually is the primary flame envelope in this case, and the blue flame is the secondary flame envelope here, so that what is normally considered as the secondary flame envelope, in this case, is actually the third envelope. How to resolve this; just don't go there. Buy or build a good enough burner to see no white in the flame, and then tune it up well enough to have very little secondary flame. The next question tends to be "how dark a blue?" Different fuels give off different hues, and lean flames are always darker blue than neutral flames in any given fuel. In fact, one burner could be run so lean that the primary flame turned purple from the amount of red that excess superheated oxygen could be included in it. On the other hand, any slightest tinge of green in the flame is an unmistakable sign that it is way too fuel rich; such a flame will be pumping out dangerous amounts of carbon monoxide. The simplest way to judge a neutral flame is that it’s blue is a lighter hue, and it has very little to no secondary flame; any darkening beyond that is from too much oxygen; it is no called a lean flame. You can also get thin yellow and red streaks in a perfectly tuned burner's flame, due to breakdown products of oxidation from some alloys of stainless steel, mild steel, or cast iron in a flame retention nozzle. Flame nozzles of #304 stainless can put on quite a show that way; it's harmless. #316 stainless make fewer streaks.

Proven burners are sooooo nice when it comes time to tune your forge...

Refractory grog can be made of anything from pottery to firebrick, which has been ground down to small particles ( ex. as fine as beach sand). It is usual for high alumina refractory to contain high alumina grog. An insulating high alumina refractory will also contain miniature bubbles of alumina or silica, which also helps with dimensional stability; this is probably why the Kast-O-lite brand of castable refractory is extra tough.

Ah yes; the good old days again...not I first began using worm drive clamps to fix previous 'repair' jobs from so-called hose repair kits, which suddenly started leaking.

Enough with the refractory cement already Different efractory cement brands are as unlike as castable refractory brands are. One thing they all have in common is a complete absence of grog. Grog is needed to provide dimensional stability, to keep a thick layer of refractory, like a forge hot-face from cracking apart under repeated thermal cycling. Refractory types of cement are made to glue refractory bricks together, with thin layers.

Refractory cements differ as much as castable refractories do. One thing they all have in common is a complete absence of grog. Grog is needed to provide dimensional stability, to keep a thick layer of refractory, like a forge hot-face from cracking apart under repeated thermal cycling. Refracory cements are made to glue refractory bricks together, with thin layers.

Well, you choose the only smart choice of clamp for creating a gas-tight seal on rubber hoses placed over barbed fittings. Most hose clamps on the market are meant to be fluid-tight; not gas -tight. You are right that people want to buy a high-quality clamp too. One good clamp from an auto part store beats a whole box of marginal clamps.

One of the reasons I'm tolerant of people's choices in heaters is that they can always be upgraded. So weed burners can be switched out for forge burners whenever someone decides they don't like a large fuel bill.

It would be interesting to experiment with the salvaged burners. It would be practical to listen to their advice instead.

You need to find a steel (preferably stainless) pipe or tube that will fit tightly over the brass flame retention nozzle on the little propane torch and cut off a part that is a little longer than your present nozzle. Gently tap the part over that nozzle, and use the torch as your forge burner that way; otherwise, your present flame nozzle will probably melt in short order.

I hope you mean worm gear drive hose clamps.

The easiest way to provide a strong light forge shell is with steel containers. Just as coffee cans make tiny forges, steel drums provide shells for large forges; everything from lube tanks to oil drums. Automotive garages can provide everything from 15 to 50-gallon drums.

You thought wrong.

There is the "superior" and the "acceptable"; they have no problem with each other. We have a problem remembering to pick between them deliberately. Deliberate, then take your choice, and don't sweat the difference. Also, accepting good enough allows you to take a later run at the problem without all that self-generated pressure

Large tanks are fine to use, but not so fine to move around to get them filled. Smaller tanks can be ganged together, to slow draw rates and avoid freezing just as well as large tanks.

Not the end of the matter A fuel rich flame in equals dragon's breath out. On the other hand, lots of such burners heat forges up just fine. This is one of those factors, that isn't necessarily a problem. But something that needs to be understood; not just excepted on the one hand, nor worried about on the other. Dragon's breath will produce more heat in your shop, and increase pollution in its air, increasing the need to blow out old air and replace it with new air. A CO monitor becomes critical. Also, all of that dragon's breath is wasted fuel. If you do these things, dragon's breath is an irritation; not a game stopper. There comes a point when you FEEL like you have a crisis on your hands, as you try to tune a new burner; and that is likely an overreaction. Sometimes it is better to accept half a loaf and revisit the problem later.