Mikey98118

AxL said "So if I understand you correctly, since the large end of the reducer is 2", the inner diameter of the tube i use should be 1/2" (for a 4:1 ratio)? And the length of the tube, by rule of thumb, should be 4.5"? I will likely turn the tube on a lathe to get the dimensions just right. I have different sizes of MIG tip available, in metric. 0.8mm (0.031") and 1.0mm (0.039") Not sure what it corresponds to in actual size. What would be you recommendation? I'm running approx. 2.2 psi/150mbar off my regulator. I'll try to get started on the construction tomorrow and come back with pictures." Thanks! I have already perfected 3/4" linear burners using 2" x 3/4" reducers (see the MIG tip upgrade on Ron Reil's burner pages). You don't always need to reach for theoretical limits in the parts, to achieve your goals. You just need to get close enough to provide the mixture flow needed to build a very hot burner. However, if you don't want to weld or braze the mixing tube in place, you will be forced to change reducer fittings, or settle for a 1/2" burner. Welding the two parts together will require #309 welding rod. Brazing the reducer and mixing tube together will require stainless steel brazing flux and 50% or greater silver content filler alloy. Also, you will have to use a special flat washer to insure that the gas jet is trapped dead center in the the mixing tube, during mounting of the assembly and saddle fitting, or else use a wooden handle with a 1/4" hole in one end (to hold the MIG tip centered), to do so. Use the actual inside diameter of the pipe or tube you use; not the nominal call out size. Also, you would use the full length of the mixing tube, if it slides inside of the small end of a reducer fitting, but only the remaining distance beyond the small end of the fitting, if it is attached to it, instead of trapped within it.

I have already perfected 3/4" linear burners using 2" x 3/4" reducers (see the MIG tip upgrade on Ron Reil's burner pages). You don't always need to reach for theoretical limits in the parts, to achieve your goals. You just need to get close enough to provide the mixture flow needed to build a very hot burner. However, if you don't want to weld or braze the mixing tube in place, you will be forced to change reducer fittings, or settle for a 1/2" burner. Welding the two parts together will require #309 welding rod. Brazing the reducer and mixing tube together will require stainless steel brazing flux and 50% or greater silver content filler alloy. Also, you will have to use a special flat washer to insure that the gas jet is trapped dead center in the the mixing tube, during mounting of the assembly and saddle fitting, or else use a wooden handle with a 1/4" hole in one end (to hold the MIG tip centered), to do so. Use the actual inside diameter of the pipe or tube you use; not the nominal call out size. Also, you would use the full length of the mixing tube, if it slides inside of the small end of a reducer fitting, but only the remaining distance beyond the small end of the fitting, if it is attached to it, instead of trapped within it.

And I agree; it is total overkill. One 3/4" burner, with that flame, should bring a forge, properly constructed from a five gallon (20 lb.) propane cylinder to yellow heat. If you wanted more even heat throughout, you would need two 1/2" size burners (of that potency).

Reducers for linear burners Concentric reducer fittings are pipe parts. Concentric reducers come in two kinds; threaded, and but-weld. Threaded pipe fittings are becoming scarce and cheaply made; this contributes to squat shapes (poor flow dynamics), and misaligned threading jobs, which are notorious for being out of axial alignment. If you want to end up paying a lot in time and money for a second rate burner, threaded fittings are the shortest rout there. Stainless steel pipe fittings just scream "expensive"! But the greatest factor in the cost of pipe fittings is how fast they move off the seller's shelf. Stainless steel but-weld parts outsell mild steel parts so much that they cost about the same; sometimes a lot less. You may need to lay out three reasonably equidistant threaded holes near to the small end of of the fitting. I like to use stainless steel socket set screws to firmly hold the burner's mixing tube within the small end of the reducer, (but these screws can be changed out later, so use whatever is convenient to begin with). Mechanically joining the parts together has several advantages: First, it reduces the size of the inside diameter of the mixing tube in relation to the large end of the reducer fitting. In a fan blown burner the ratio of the fan blade to the inside diameter of the burner should be no more than 3:1, to avoid dangerous back pressure at the reducer/fan assembly joint. But in a naturally aspirated linear burner 3:1 is the smallest acceptable ratio, and 4:1 is much better. It is desirable to be able to separate the reducer from the mixing tube when aiming, and later in adjusting, the gas jet. Finally, being able to change out mixing tubes can allow a single burner to be reconfigured as different burner sizes later on, as you find desirable. Note: You can help adjust ratios with the thickness of the mixing tube's wall, and by grinding the inside of the large opening in the reducer fitting to form a long inner taper, which works much better for air flow than a short inner bevel. by inserting a beveled spacer ring between the reducer's small end, and the mixing tube, can be made to fit up properly with even smaller mixing tubes. The mixing tube should be "seamless"; otherwise you may need to grind down the inner weld bead which is often found in cheap pipe. Steel tubing has better tolerances than are found in pipe. The three screws (which are recommended in the reducer fitting) can be reduced to a singe screw, IF the mixing tube and reducer can be made to fit snugly together buy twisting (rotating) the two parts against each other. On the other hand, a really sloppy fit could require six screws. The mixing tube's end must be beveled at least sixty degrees on its inner wall, to facilitate air flow; this doesn't need to be done at the beginning of construction, but can be left as final improvements to bring a weaker burner up to full power. As a general rule the length of your mixing tube should be nine times its inside diameter; ten diameters can be used to insure a smooth flame in hand held burners, and eight diameters can be used to shorten a flame, in case of limited available room for the flame path. Do this much, and then I will provide further instructions.

Very well; let's start with the stainless steel reducer fitting in your photos: You may need to lay out three reasonably equidistant threaded holes near to the small end of of the fitting. I like to use stainless steel socket set screws to firmly hold the burner's mixing tube within the small end of the reducer, (but these screws can be changed out later, so use whatever is convenient to begin with). Mechanically joining the parts together has several advantages: First, it reduces the size of the inside diameter of the mixing tube in relation to the large end of the reducer fitting. In a fan blown burner the ratio of the fan blade to the inside diameter of the burner should be no more than 3:1, so to avoid dangerous back pressure at the reducer/fan assembly joint. But in a naturally aspirated linear burner 3:1 is the smallest acceptable ratio, and 4:1 is better. It is desirable to be able to separate the reducer from the mixing tube when assembling, and later in adjusting, the gas jet. Finally, being able to change out mixing tubes can allow a single burner to be reconfigured as different burner sizes later on, as you find desirable. Note: You can help adjust ratios with the thickness of the mixing tube's wall, and by grinding the inside of the large opening in the reducer fitting to form a long inner taper, which works much better for air flow than a short inner bevel. by inserting a beveled spacer ring between the reducers small end and the mixing tube oversize reducers can be made to fit up properly with even smaller mixing tubes. The mixing tube should be "seamless"; otherwise you may need to grind down the inner weld bead which is often found in cheapest pipe. Steel tubing has better tolerances than are found in pipe. The three screws (which are recommended in the reducer fitting) can be reduced to a singe screw, IF the mixing tube and reducer can be made to fit snugly together buy twisting (rotating) the two parts against each other. On the other hand, a really sloppy fit could require six screws. The mixing tube's end must be beveled at least sixty degrees on its inner wall, to facilitate air flow; this doesn't need to be done at the beginning of construction, but can be lect as final improvements to bring a weaker burner up to full power. As a general rule the length of your mixing tube should be nine times its inside diameter; ten diameters can be used to insure a smooth flame in hand held burners, and eight diameters can be used to shorten a flame, in case of limited available room for the flame path.

I often move my comments in other threads, to Forges 101, and change the text enough to keep the subject clear for readers there. I would like to see what you had to say here, in that more permanent thread; the subject is as important as any other in that tjread.

Frosty is right. Much of what you see and read of Youtube is what I call "happy talk", but urban legends is a dead on description. You can find good ideas on YouTube, but in trying to winnow them from all the outright horrifying advice, you would need to already know all the right answers. Its kind of a question of the blind leading the blind

To begin with, what you have built so far, is called a side-arm burner; it is a failed design. You would be much better off to rebuild it into a "T" burner. Rejoice! Your minor burner problem has slowed you down enough to fix a major problem with your forge, before its too late. You need to re-position your burner opening, so the the burner's flame will impinge on the forge floor's nearest to the burner side, and about one-third of the way in from the floor's near edge; this will give you the best use from your forge. Where the burner opening is positioned now, would give you the least heat in exchange for the shortest use of your insulting refractory wall; a very bad bargain indeed. You lucky devil; aren't you glad you had burner problems now?

Yes, and some even started out listing it, at a possible health product; for use as an antioxidant; apparently it is very reactive in human tissues; then they started finding it can enter cells, and now it is starting to be warned against. We don't want any brave souls achieving their Darwin awards, while officialdom is making up their minds, do we? The problem is that health issues have become just another political football.

Frosty, You will have to dig hard to find any specific information on percentage of I.R. re-emission from cerium oxide; if I run across any such numbers, I will post them. What I found was mostly strewn through half a dozen inclusions of cerium oxide as a preferred emission agent, in lists of them in various patents for heat reflection coverings. I had already run across it is one of the substances used for stabilizing zirconia. And this, along with cerium oxide's vary small particles, (which is a natural outcome of its processing, rather than any need for grinding), decided me to include it with any future zirconia oxide of zirconium silicate based refractories and heat reflective coatings from now on. One of the other ingredients I noted in heat reflection coatings was silica; a preferred binding agent, because it passes radiant energy well. This makes me feel much better about using zirconium silicate in place of expensive stabilized zirconia flour in heat reflection formulas.

This stuff used to slip under my radar most of the time, too. I've slowed down so much mentally, that the obvious is no longer beneath me

Which leads to the question of what would make a good axe forge; probably a "D" forge, or an oval forge, to get a wider floor area.

Cerium oxide Cerium oxide (CeO2) is an even more famous emissions agent than zirconia, is used as a stabilizing agent for zirconia oxide, and its flour (nanopowder) costs about one fifth that of zirconia oxide flour. Moreover cerium oxide nanoparticles disperse well into other mixtures. I think it might bump up performance levels of heat reflection in zirconium silicate refractories, and could partner with Veegum T as the ultimate homemade heat reflective coating. Warning: Use a respirator; you DO NOT WANT this stuff entering your lungs!

I'm hoping that the photo will be something of a revelation to other folks, about how big differences don't always need big changes; looking forward to seeing the next photo.

You are more than welcome Square Nail. do weuns get to look too?

Nothing is obvious to an anxious mind. Take flame paths; the longer the better is a given. But, take a careful look at your forge: (1) Is your back wall closed, accept for a SMALL opening to occasionally pass long material through? Do you keep it closed when not in use? If not, you are shortening some of the flame's exit path, and wasting fuel. (2) No two burners have identical flames; this goes double for homemade burners. If you have two or more burners, are they positioned so that the richest burner is at the back of the forge, and the leaner burning is forward of it? If you have three burners, and one burner is burning rich, one neutral, and one lean, they should be positioned as; back wall, than rich, than neutral, than lean, and than exhaust opening. (3) A swirling flame path is a long flame path. But is isn't always possible to position your burner on a tangent. You may choose, for perfectly logical reasons to build a box forge; and their a lots of old box forges that you may decide to buy, and recondition. If you can't position the burner for a long flame path, try to produce a shorter flame. Multiple flame ceramic heads, such as found on ribbon burners, and Giberson style ceramic heads are the best choice for creating short hot flames. But many burners have a fast enough mixture flow to allow deliberate shortening the mixing tube, or mounting a radical flame nozzle, which will create a shorter brush flame. Nothing tried means nothing gained...

Looking at the one clear flame photo, I would make one last helpful change. Move the front burner, that has a lightly reducing flame to the back of the forge, and move the back burner that has a neutral flame to the front of the forge. This allows more distance for the secondary flame to burn off, and insures that the fuel that didn't burn, must pass in front of a neutral flame before it exits the forge. Better results all the way around for a small additional effort, yes?

Larry, I find myself underwhelmed...and that is just WRONG! It is important to get behind products that are investing in their customers safety. Recently, I even thought about looking for a source of asbestos, just to solve some technical problems; Maybe it's because I'm old. But there are a lot of young people, who still need to guard their health. Bravo, for doing something constructive about the future

thanks; every supplier we can come up with helps.

Morgan Crucible company's 2600 F rated insulating fire bricks make a good balance of endurance and fuel efficiency. A heat reflection coating should bring them completely up to snuff for holding up to flame impingement, while increasing fuel efficiency even further. Do not use foamed clay fire brick as primary insulation; they have nearly zero mechanical strength, and crumble from thermal cycling. Semi-insulating alumina fire bricks have much more strength, but as is true of refractories, not all 2600 bricks are the same. Morgan claims their bricks to be much more insulating than other brands, because they have more micro-pores, which better block heating by conduction. A good indication of a material’s ability to slow heat conduction is its weight. The average 2600 aluminum based refractory is 85 lbs. to the cubic foot; bricks made out of it weigh the same. Morgan’s 2600 bricks are aerated during construction, and weigh only 45 pounds to the cubic foot. I have been looking for a reasonably priced alternative to ceramic fiber board for years; This looks to be it. Alumina brick can be cut using ceramic rated cutoff disks in saws, and angle grinders, and drilled using carbide encrusted hole saws, and carbide tipped cement drilling bits.

The 1" thick version of these bricks make the perfect transition layer to place between a high alumina kiln shelf and a pillowing layer of ceramic fiber insulation, to protect it from being overheated by the shelf temperatures.

2600 semi-hard & semi-insulating fire brick "Thermal Ceramics, a division of the Morgan Crucible Co., England, has recently introduced a new product, K(R)-26 IFB. Historically, 2600F grade insulating firebrick have been relatively dense materials, generally produced by a pressing or wet compaction process. In 1998 Thermal Ceramics began extensive development efforts with the aim to produce a 2600F insulating firebrick using the company's unique casting process. The result of these efforts is the new K-26 IFB. Until now the advantages of the casting process -- more micro-porosity which improves thermal conductivity -- were not available in a 2600-degree brick. At a mean temperature of 2000F, the K-26 IFB performs equivalent to lower temperature IFB such as the K(R)-23 and the K(R)-25 on thermal conductivity value and substantially outperforms ceramic fiber blanket at temperatures higher than 2000F. And at a density of 40 lbs/ft(3), K-26 IFB is roughly equivalent to K-25 (2500) IFB." The company's website is located at http://www.thermalceramics.com Note: The only reason that this product will perform as well in ceramic fiber insulation at 2000 F is that most of the heat transfer at that temperature (and up) is by radiation; not by conduction. This means that only the portion of either product this can be applied to is the part that is at yellow incandescence. eBay source of 2600 insulating fire bricks: https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1311.R1.TR6.TRC1.A0.H1.Xinsulating+f.TRS0&_nkw=insulating+fire+brick&_sacat=0 These bricks are semi-insulating, and be considered half-hard; they can stand up to thermal cycling without crumbling, and wont fracture from careful handling, but can be improved in mechanical strength, resistant to hot flux, and insulation value with a coating of zirconium silicate/Veegum homemade refractory For all you people who buy half bricks to save money and trouble; here is a much better choice (even without the coating).

You are between a brick and a hard shell Without dissing your forge, it boils down to a question of room. You need a tough hot-face on the one hand, and insulating qualities on the other; your forge just doesn't have the room to give enough insulation and maintain physically tough interior surfaces. So, compromise with a good tough semi-insulating hard refractory like Kast-O-lite 2600. Kayolite brand has a good variety of insulating and semi-insulating hard refractories, too; look them up. Building a shellacked wood form to cast your own brick floor in, is simple. You can buy either brand of refractory in small amounts from re-sellers (like Wayne on this very forum). Go to the Forges 101 thread, and read up about zirconia silicate homemade refractory and kiln wash, which will reflect heat back into the forge. You can buy the supplies at most pottery supply stores. You wont lose or gain any money going this rout, but you will save a whole lot of fuel, and gain a lot tougher forge.

Dead on. Home founders like to use them to check crucible contents for pouring temperature; some guys have set up their casting furnace with a small peep hole to run the ceramic sheiled thermocouple through, but it would be more useful to check for tempering temperatures; they consider the thermocouple to be just another consumable.

MonkeyForge, Feel free to add anything you care to on the subject of sintering. Please note that the author of the article in DigitalFire on making rirconium silicate refractories, talked about using batts to help dry his tile, and warned that the amount of water had to be kept to a minimum. Myfordboy has a video on YouTube, showing how he uses a hand operated vibrator to liquefy castable refractory, which contains very little water content, into a mold. I think vibration will be key to success in molding or casting these formulas. Good point; I will be more specific in future.This stuff can be used as both a thin heat reflective coating at 5% Veegum (or Bentonite clay) and as a 3/16" and thicker refractory at 3.5%; the difference being that the author stated that it becomes "sticky" with the higher percentage of plasticizer/binder. Sticky is a very desirable quality in a thin coating, but a real pain in a general refractory. Home founders like to build vibrating plates for sand screens to set on; the same scheme should be a simple method for vibrating small molds for casting tile, etc.