Mikey98118

Preheating propane was a long running debate on the various home casting groups; I didn't get involved, because I felt it was two steps back for one step forward, trading away safety for some increased flame temperature; not my kind of deal.

Thanks Frosty, That was a handy hint about why colors show up so different from cameras.

Well, no; the process of using high fuel pressure in a gas jet to induct air can just as easily be reversed, using compressed or fan-blown air to help draw low pressure natural gas into a burner. Nevertheless, you'll have to spend quite a lot of money to have a certified plumber lay gas pipe into the garage, in order to save a little money on piped gas over the price of compresed LPG.

Good; the next thing you'll want to do is rigidize the ceramic fiber, and then flame cure it. Rigidizer is simply fumed silca (a colloidal substance). suspended in water, with enough food coloring for you to be able to see how deeply you are penetrating the fiber blanket, when you use a spritzer to apply it. There is no need to wait for the blanket to dry, as you must heat cure it with the burners. At present, eBay has the best offers for this product. You should look up the various posts on homemade kiln wash

Frosty, I think we can do better than a politician's honesty with color charts, but question if we will bother to.

Wayne, This is one of my favorite disputed confusing brain-teaser subjects; I'm right glad you brought it up Yes, using the same amount of ambient light to judge incandescent colors is fundamental; I suspect this may be why videos and still shots can be so misleading. I like to do my color judging on overclouded days or at twilight in summer months. So, how to resolve this? There are color charts available on a few blacksmith sites, listing degrees by color. But to match up one of the colors on the chart a test is needed; most of these charts start with 1200 degrees as barely luminous when seen in poor light. Aluminum melts at 1175 to 1200 degrees, depending on the alloy. An aluminum welding (not brazing) rod will suddenly slump, telling you when that heat is reached. There are also "heat sticks" available in or through some welding supply dealers to indicate when various temperatures are reached; you can choose one for red heat (1500 F), and experiment with the shop lighting until your chart's color heat matches with the heat stick, then use that level of ambient lighting to "calibrate" your color chart with desired temperature. For me, in my shop, with the same lighting. yellowish white is 2000 F, blinding white is 2300 F...more or less, and temperatures above that are too much for this old man's eyes. Anyone can refine the system as much as desired. Some people are partially or completely color blind, but I haven't run across any evidence that we all see colors differently. So, by giving the color chart source being used (because they don't all agree) running a test, and keeping the same amount of ambient light, during color judging, blacksmiths should be able to agree on what colors go where, and why. If any of us care that much...

FC, You can get all the specific details and background facts you want from reading Gas Burners for Forges, Furnaces, & Kilns. Go to the Amazon.com book section and input the title; look through the book to reassure yourself that it is FILLED with answers to specific questions, which apply to all burner and forges; not just specifics about my burners and my forges. You don't even need to buy the book, since it started being pirated and free downloads offered on various sites a decade ago. Just be careful about what site you download the PDF from, and then keep a cup of coffee handy; there are enough specific answers in every chapter to roll your eyes up in your head without a lot of caffeine assistance. My own family couldn't make it through more than a few pages, but then, none of them wanted to build anything A lot of your questions will be answered just by viewing the 120 drawings in it. And no, I don't worry about pirating hurting book sales, which have more than double since all that pirating started.

You mentioned the Adam, The work and expense you've invested in that forge probably looks like a waste right now; it isn't. In fact your problems are minor and easily fixed, IF you address them one at a time. You said "It makes a nice blue-green flame. The weird thing is that the area right below the flame isn't nearly as hot as the area around the flame." A blue-green flame is a seriously reducing flame, which is shown by the fact that it has to finish combustion elsewhere in the forge interior; this is why the flame impingment area is cooler than its surrounding area. The area where the flame impinges should be hotter than its surroundings; not cooler. To prove my point, light up the forge, and then walk over to the light switch. Turn off the switch and watch all the pretty blue carbon monoxide rich flames exiting out the exhaust opening. Your next step is to build the Two "T" burners ans screw them into the forge; the other changes you need to make are simply add-on work, but I'm not giving any more advice until you act on this.

Adam, the problem is that your rows of holes create massive turbulence. Some turbulence is needed for good fuel gas and air mixing; that would be a little turbulence, not massive amounts, which is like trying to get good performance out a car with the hand brake engaged. the other problem with a row of holes is that nearly everyone who takes this rout places their gas jet near the back of the rows, instead of mounting the jet on 1/8" pipe, so that they can slide it forward and experiment to find where its best position might be (probably in the middle of the forward holes). Probably the easiest fix at this point would be to build two Frosty "T" burners and screw these easily constructed powerful burners into the forge, in place of those poorly designed and way overly long burners you are suffering with at present. But, don't throw you present burners away; instead offer them to the first person who tells you how wonderful the design looks on YouTube. You can save them some wasted effort and money.

norrin_radd, Can this thread be found again in a a couple of years? I would like to list it too, but not if it just frustrates my readers. As with the first book, I'd like to include three or four pieces of heating equipment in the next book; different equipment for each book of course. After Vortex Burners, I want to do a general survey and build text on each type of burner; naturally aspirated linear and jet-ejectors, ribbon burners, ordinary old style fan-blown, and powered vortex; with a couple of examples of heating equipment for each type of burner. And what I've learned over the last sixteen years about homemade rigidizer, high-emissive coatings, and superior refractories. Frosty, I'm going to try your kiln wash soon; now that it is for certain available at Seattle Pottery Supply, which is a local store, and famous for reasonable prices on all of their raw materials, and also because zirconium silicate will insulate better in thicker coatings, just like any zirconium based product, while ITC-100 can only be used in pretty thin layers

Wayne, Isn't 2300 F reached at white heat? Of course the indications of heat after that are too subtle to do any good, but couldn't the operator adjust flame amounts to keep the forge pretty close, visually? This is just a guess on my part.

Hi Harry, The stand looks fine to me, but please don't let anyone talk you into positioning a propane cylinder underneath a heat source; that's like begging for trouble with your local fire department. People see propane cylinders placed under barbecues and some shop heaters, and assume doing so with homemade heating equipment is okay; it's not. The commercially built examples I used are "grandfathered in" exceptions to national and local fire codes; if not, they would not be allowed under today's fire codes.

Adam, Your still shots looked pretty discouraging, but the yellow enterior shown in the video is much more encouraging. Not only is that standard "T" wrong for Larry Zoeller's modified side arm burner, but it is positioned out of line; a problem that you cannot remedy with a threaded part. The best solution for all your burner problems is to salvage some of the pipe fittings, and build a "T" burner instead; it is the only burner design I know of that can overcome faulty threaded cast fittings, and is a more powerful burner anyway.

It's been about fifteen years since I taught a class in the garage, which now resembles The Dark Hole of Calcutta; that was much more satisfying than writing books...hmm.

Charlotte, If we completely agreed, one of us would be unnecessary to this conversation; nor do I desire for things to be done my way. It is my desire for readers to look at both sides of the coin and make up their own minds as to what they think. I enjoy your differing views, quite as much as Frosty's.

So, if we aren't sure how much thermal loading is optimal in our forge, what then? Who says all thermal mass must be built in? Nothing prevents you from including extra thermal mass on top of the forge floor, on a temporary basis, when heating large parts, and storing it when heating small parts? You can see this very trick used in one of the Chile Forge videos.

Bird, If you want a demonstration of what high-alumina kiln shelving for an all around hot face in a forge can do, have a look at http://www.chileforge.com/

BTW Charlotte, I found most of what you had to say quite educational. Thank you for that.

Wayne, I hear what you're saying and agree with your conclusions, but the desires of the average kid to skip straight to what they want, strongly indicates no driving interest in learning anything, but rather it points to a "gimme, gimme" attitude. So maybe we aren't so much disagreeing as fulfilling the old saw that goes " it's six, I tell ya; no, no, its half a dozen!" Often a truth can only be seen, when conflicting ideas are held in balance against each other.

So, if clay is a combination of aluminum oxide, and natural glass, why would high-alumina be so different from it? High-alumina is short for high purity alumina a manufactured form of aluminum oxide used as the refractory concrete, with the same very pure aluminum oxide as grog, and with a very small amount of calcium alumina as binder, instead of a large amount of glass as the binder. Whether you are considering fine china or a lump of clay from your backyard, it is the glass content in the ceramic that is mainly responsible for heat transfer. To demonstrate the difference, purchase a small high-alumina crucible from eBay, and line it up with a ceramic coffee cup and small glass container; pour hot water into all three containers and touch them; no contest! the culprit in high heat transfer is the glass content.

Why isn't everyone familiar with heat transfer blocking versus heat insulating refractory products? Because the only information you get about resisting heat transfer comes by reading the numbers given (sometimes) for heat transfer ratings. If you want to know the how and why of those figures, you must research crucible materials and coatings; that's where I came across the "seven times" rule of thumb, and also where I learned about high-emissive coatings.

I think even heavy weight Mizzou castables are high alumina based refractories these days, so the seven times more resistant to heat fransfer than clay based refractories still applies.

Charlotte, Your engineer was being sloppy in his thinking. Standard clay based hard firebrick is practically transparent to heat transfer. With high alumina based brick, castable refractory, or kiln shelves, this just ain't so; it especially ain't so with an insulating alumina based semi insulating refractory like Kast-0-lite 30, which is rated at 4.54 degrees of heat loss per hour, per inch at 2000 F; that is hardly transparent!!! Nevertheless a 1" thick hot-face layer of this stuff will also provide as much thermal loading as you can use in a gas forge. or home built casting furnace. Of course there "ain't no free lunch." So what is the down side? About ten extra minutes reaching yellow-white heat (with a high-emissive coating, such as ITC #100, and an effective burner). The upside is that you quickly recoup those lost ten minutes, if you're doing more than an hour's worth of forging or casting

Bird asks, "So I should cast thicker floors and use lighter walls for best performance?" Answer: Not exactly--for best balance between performance and durability. If you are looking for performance alone, thermal loading is still an open subject, because you haven't included what size and how much material you are heating, and how fast you can forge or weld the parts you are heating. A properly built gas forge with a hot running burner will heat parts faster than most smiths can keep up, without thermal loading, beyond a high- alumina kiln shelf for a floor. "What do you think is an optimal wall/arch construction for balance of performance and durability?" Answer: Since you included durability in your second question; an inner hot-face layer of Kast-O-lite 30 1" thick shaped in a "D" pattern, with the flat side on the bottom to create a forge floor. After the hot-face layer is cast and heat cured, wrap it in ceramic fiber; compress the spring fiber in twin so you come up with a denser outer wall of insulation. Install this in a Freon or propane cilinder (depending on if you want a general size or knife maker size gas forge). Cut the cylinder lengthwise and install a piano hinge on one side, and threaded latches on the other side, As Wayne recommends in his forge build method, because it will make installation of the ceramics much simpler, and accesse to the forge enterior for maintaince as well. You will also want to include a folded "pillow" of ceramic fiber underneath the floor area. End enclosures of ceramic fiberboard can be installed the most easily in this construction scheme, and will hold up better than 2" of ceramic blanket, but cost a lot more to use. some extra struggle followed by rigidizer, and then coated with whatever homemade "kiln wash or other heat reflective coating you desire on the cast hot-face inner layer, will also do wonders to preserve ceramic fiber blanket enclosures too.

Frosty, Back when I was writing Gas Burners for Forges, Furnaces, and Kilns, I began my research on applicable safety codes by looking up posted information on Propane Association web sites. I then went on to posted information on NFPA member sites, since I didn't want to pay for an authorized copy of the national fire codes, from which nearly all local fire codes are derived. But it's been sixteen years, and everything changes on the Net over time; sometimes mere months of it. So to provide that information I'd have to spend money or months finding the information again, and just don't have enough interest left to revisit a subject that holds very little interest for most people. also, I did not say that torch carts are illegal; I said they weren't legal to use in shops, and as used by most people in the field. I also said that this rule is almost universally ignored with impunity, except when the fuel gas is propane, and stated why (thousands of incidents where the over-pressure safety valve releases a cloud of highly flammable gas; over-pressure valves on propane cylinders are set for very low pressure release because of the thin cylinder wall, as compared to other fuel gases, which come in cylinders with much heavier wall thickness).