I used an old orbital hand sander, without the sandpaper. It produced just enough vibration to settle the mix.

I can't control the wind, all I can do is adjust my sail’s.~ Semper Paratus

That was a good one. Any more ideas floating around out there?

At present, I believe that Chile Forge is the top-of-the-line forge offered for commercial work (for a slower pace, I would go with a single burner Diamondback, for their reliability). Do I think there is a better forge for doing commercial work than the largest Chile forge? No; but a properly built ribbon burner forge will get almost as hot with a smaller fuel bill, and should cost about one-sixth the money, plus some sweat equity, to build. Do I believe this is true across the board, size wise? No; at present, ribbon burners are most efficient in larger equipment; this may not hold true of other multi-flame burner designs.

    A gas forge made from a five-gallon propane cylinder is the smallest size I would heat with a ribbon burner, so it makes a good example to use, if we want to test the limits of ribbon burner superiority. Using two ½” high-speed tube burners, instead of a single ¾” burner, and a movable internal baffle wall, will allow this forge to equal the ribbon burner’s efficiency on small work, and that is as good as you can do; this isn’t a win against ribbon burners, but cuts your losses enough to extend how far single flame burners may compete with multi-flame burners. With smaller forge sizes, single flame burners, if well built, can hold their own. On the other hand, if you build a combination forge/casting furnace, a ribbon burner is impractical.

On 12/12/2024 at 1:48 PM, Mikey98118 said:

at present, ribbon burners are most efficient in larger equipment; this may not hold true of other multi-flame burner designs.

What other multi-flame burners would this be? Well, there is the Giberson 2" Mini-Square Giberson Head; a ceramic plenum chamber, which is designed to be screwed directly unto a burner's mixing tube that ends in a pipe thread, has been around for several years.

On the other hand, there are guys on IFI who have posted photos of burners, with flame retention nozzles that are made from a pipe reducer fitting, with a drilled stainless steel face plate; this creates multiple small flames.

Giberson's ceramic burner heads are on one end of the spectrum, while pipe reducer fittings with drilled face plates are at the other; they both work the same way.

                                                                     Doghouse forges

Pentagon shapes can be easily bent, welded, or silver brazed in position from sheet metal, but their advantages do not end there. When one or more burners are mounted in one side of its roof, they can be aimed at a convenient angle into the forge interior, while remaining perpendicular to the sheet; thus, allowing steel conduit connectors, or pipe fittings to be employed to trap burners in place. Volcano Forges were an excellent example of how well this design works out. This forge’s pentagon shell is easily filled with ceramic wool, and then rigidized into an interior shape like that found in “D” forges. But, unlike “D” forges, Doghouse forges can be lined with ceramic board, under a heat reflecting finish coat. Baffle walls made of firebrick against the rear opening, and about 1” away from the front opening complete these forges, without need of sheet metal  on either end of the forge.

Is that a brand name or a description of a forge shape? I don't get a hit for forges in a search.

Frosty The Lucky.

It is a description of the forge shape, which I picked up yesterday, from an old (2014) IFI post, which I stumbled across out there on the Net. I thought it was apt enough to bear repeating, so I did

Volcano Forges were an excellent example of how well doghouse forges work out. I few further thoughts on the matter:

    You can mark the forge’s outline on cardboard, or some other flat surface, and then draw lines parallel to the forge bottom at the same height that the materials of the forge floor will make. Next, move a square and ruler, up and down the roof line, to determine where to cut holes for the burners. You want the flames to impinge at the far end of the floor, but short of the far wall, for maximum swirl in the forge atmosphere, while missing the parts being heated.

 

Sorry for the slow reply, I started and Mr. Clock said, YOU HAVE AN APPOINTMENT GET THE HENCE!!

We discussed Volcano forges and the benefits of the shape a while ago. Didn't we settle (sort of) on . . . DRATS I don't recall! Oh okay, Doghouse works for me, for now.

Frosty The lucky.

Volcano Forges are just a memory, so why do I bring this forge idea up at all? Because some ideas take years to become popular; but, if they are good ones, there is no stopping them. Oval forges took more than a quarter century, but now they are all over the place. You know how fond I am of complicated construction choices. Nevertheless, I recognize that "simple as a mouse trap" whens out over time

                                                       Adjustable pressure regulators

The first piece of equipment attached to a refillable fuel cylinder, should be a variable pressure regulator. You cannot use an old acetylene regulator for any other fuel gas; they are illegal, and unsafe to use with LPG fuels. While you can use an industrial multi-fuel gas regulator from a torch set, LPG regulators are less expensive and better suited for use with these fuels in cold weather. I recommend using a 0 to 30 PSI model, with a pressure gauge attached, although a 0-20 PSI regulator will work okay, for most people, most of the time.   

    You can find good quality 0-30 PSI propane regulators offered on Amazon.com, or other online sources; or find them locally at most large hardware stores. If you end up with a regulator that does not have a pressure gauge, or a side port on which to install one, you can add a “T” pipe fitting at the regulator’s outlet and install a pressure gauge there, using s short pipe nipple in its end opening, a regulator outlet bushing in the other end, and the gauge screwed into middle opening. A pressure gauge should be a helpful training aid, for the novice; once familiar with their equipment, most people ignore them.    

I'm up to page 3 out of 95.   I've been debating buying a $583 Majestic Forge, but building is more satisfying.  Without the efficiency of scale manufacturers have, I don't think I can build one for less money, however.

Majestic forges were used on Forged in Fire, but does that mean they're really good?

Anyway, lots of notes written down just from the first three pages.

The simple answer is NO! I have been to their site, and can say in their defense that their product looks to have been improved. But, Diamondback forges have also been improved; I suggest you look there for your forge, to get your money's worth.

As to the idea that 'mass production' is doing anything to keep commercial forge prices down; the answer to that is a big fat NO too. Prices are based on what the market will bear--period.

Yes, you can save money by building your own gas forge; however, how much is saved is directly dependent on how much reading and thinking you do before starting work. Bottom line is that building to save money isn't a smart plan for most folks.

Building your forge will do a fine job of increasing knowledge of one of your shop tools, and if you are careful, your forge will be better than anything you can buy; that is the only way to "get your money's worth" by building a gas forge. 

You also need to do some reading, to get your money's worth when buying. After designing and building this equipment for a quarter century, that is my well considered opinion.

                               Using ceramic wool insulation and rigidizer

Even the cheapest grade ceramic fiber blanket does not melt below 3200 °F. Product temperature ratings come from the level of heat that fiber products will withstand without massive shrinkage; this should illustrate the importance of locking the individual fibers in position by rigidizing; it also demystifies the seemingly magic protection conferred by a relatively thin coat of heat reflector, such as ITC-100, or Plistix 900. Ceramic fiber products need both rigidizer and finish coatings to do well in today's gas forges; this is because better burner designs and smarter forge designs create much higher internal temperatures than were common in the past. 

    Rigidizer is especially important, because if you want your insulation to last, it must be prevented as much as possible from shrinking. On the other hand, between employing 2600 °F or even 2900 °F rated ceramic fiber insulation and rigidizer, you can toughen the secondary insulation layer in your forge or furnace enough so that it should stand up well to the heat that will leak past the high emission coating (AKA IR reflector) and thin hot-face layer (typically Kast-O-lite 30 for many years. Rigidizer also helps support thin flame face coatings. There are products like Plistix touted as heat reflectors, which make very nice surfaces on which to paint more effective high-emission coatings.

    You do not want to use thick fiber insulation layers, which tend to ripple when placed inside of curved surfaces; instead of a single 2" thick layer of ceramic fiber, place the blanket in two 1" thick layers. Ceramic fiber blanket will easily part into thinner layers via delamination between layers. Rigidize each layer after installation, and heat cure it, before installing the next layer. Finish forming burner openings before rigidizing each layer. remember to cut them just a little oversize so that they allow the burners to be moved without suffering damage.

 

Note: When first wetted with rigidizer, the blanket sags somewhat; this makes an excellent opportunity to push bumps flatter on its surface, and then heat them up to red incandescence with your burner, before they can raise up again. This way, you can smooth the first layer, before placing a second layer over it. Continuing this trick on the second layer will smooth its surface, before adding a flame face layer over it.

 

Rigidizer is colloidal silica (just fumed silica, which stays suspended in water) and common everyday food coloring (to allow you to visually judge how far it has penetrated); this product is easiest to dispense by spritzing after you mix up your own. But you can always pay through the nose for it, already mixed with water and a dash of food coloring, from a pottery supplies store. I bought my fumed silica powder through eBay and got free shipping, because its weight is negligible.

    Ceramic fiber products are so porous that water runs right through them, unlike solid refractory, which must be slowly dried out, and then gently heat cured to prevent damage from a buildup of steam pressure. So, ceramic fiber can be "cured as you go," which means that nothing prevents you from slowly rotating a layer of blanket on a curved surface, like a casting furnace or tube forge, spritzing the rigidizer unto each area that is laid flatter by the weight of the liquid, using your burner (turned down low and constantly moving over the wet fiber), to stiffen the blanket into permanent shape, and then moving on to the next area at your convenience. After creating a smooth stiff surface inside the structure, you can install another layer over it, the same way.

    One of the advantages in completely soaking the blanket through is that both layers will bond together. Any excess rigidizer that soaks into the first layer will run right over its fiber’s surfaces by capillary action, the same as it did the first time, causing no clumping to degrade the insulating value of the first fiber layer.

    The whole process is nearly goofproof. But it is still possible for a complete idiot to burn himself with the escaping steam that will be created, during firing. If you turn a high-speed burner on at maximum while holding still over one spot, it is conceivable (but quite unlikely) that you could even shrink a patch of fiber.

    What keeps Murphy’s Law from messing up your efforts? First, the fiber is partly alumina, and partly silica; the aluminum oxide (Al2O3) pretty much prevents it from melting, while the silicon dioxide (SiO2) bonds beautifully to the glass surface left from the old rigidizer. Secondly, the individual fibers in the blanket are very thin, which maximizes capillary action of a liquid across their surfaces. During heat curing, the colloidal silica that has wet every bit of fiber becomes a permanent vitreous outer layer on them, which creates welded joints everywhere the fibers cross each other. This glass sheathing is permanent. More rigidizer applied over it simply adds another ultra thin layer after the next heat. Glass (silicon) is heavy, yet a quart jar of foamed silica (which forms colloidal silica in water) is so light that the plastic container is heavier than all of its contents; this is because colloidal silica particles are so small that the main ingredient in the jar is air. Their tiny size is also why the powder will melt unto the ceramic fiber surfaces, this one time, at red heat. Afterward it remains solid at yellow heat. Consequently, every layer of silica sheathing on the ceramic fiber remains so thin as to leave the insulating ability of the blanket unchanged, even after repeated applications.

 

Note: If you do not completely dry the rigidized blanket before coating the blanket layers with sealant, it can still create a steam pressure problem, damaging the seal coating. So, drill a 1/8” hole in the bottom of the equipment’s steel shell, as a pressure valve, and seep hole.

 

You can buy colloidal silica rigidizer at some pottery supply stores, but being mostly water, it is not cheap to ship from online sources; in that case you are better off to mix your own. Commercial solutions usually contain about 1100 grams of colloidal grade silica per liter of water. A liter is just over one quart (just under 34 ounces), if you want to use a kitchen measuring cup. One easily found and economical source of colloidal grade silica is fumed silica, which can be purchased from eBay, Amazon.com, and many other suppliers. To assure receiving the right form of fumed silica, input “rigidizer” in your Google search. Also make sure the product says powder; so that it’s not already mixed with water, if you don’t want to pay ignorance tax to the unscrupulous.

    Unlike sodium silicate, this product must be fired to take a permanent set on the ceramic fibers. Never allow this or any other colloidal solution to freeze, or it will clump together, and be ruined. On the other hand, measuring amounts is not needed. Commercial solutions commonly contain thirty percent fumed silica in solution with water. If you make your solution too thick to spritz, just add water. Too weak? Add more fumed silica. Hard to determine how well it is penetrating the ceramic blanket? Add food coloring.

To do a good job of silver brazing burner parts together, and silver brazing parts unto forge bodies, you need to have a good view of the work.

    Green ANSI rated welding lenses, are just fine for use in torch brazing, welding, and cutting on copper, brass, and steel alloys, and are low cost. Unfortunately, you will not find one for sale in lighter than a shade #4. For silver brazing shade #3 provides the right view. However, the oldest (and therefore cheapest auto-dark lenses, which appear magenta in photos of their lens faces) provide shade #3 green views, with the same blocking of UV and IR of a glass shade #10 welding filter, in their clear states. If you look under unigoggle filters, at Amazon.com, you can pick one up for $10 to $12.

 

Auto-darken welding filters: Unlike the various types of solid glass (and polycarbonate) welding lenses, an auto-darken welding lens has a limited-service life, determined by how long it take for its rechargeable battery to wear out; some of the more expensive auto-dark lenses have replaceable batteries. However, that only affects an ADF’s dark state. its light state (AKA clear, or bright state) is built into the front glass sheet (called a UV/IR interference layer) on every auto-darken lens; also, the light state filter strength (shade #2.5, #3, #4, or #5) is built into the ultra-thin metallic coatings on that glass mirror’s front surface. The manufacturers choice of coatings on the interference layer also affects your view. Typically, there are six coatings of aluminum oxide and five layers of silver oxide. Some interference layers include a gold coating on top of the silver and aluminum coatings.

    If you see a magenta color in the front surface of an auto-darken filter in photos, its coatings provide a green view, which is no different than a standard ANSI filter of the same shade as the filter’s clear state. If you see a smoky, or light blue surface in photos, you are probably looking at what is called a true color auto-darken lens. You can add colored polyester film, or a thin acrylic sheet behind such a filter, to manipulate your color view as desired. Some gold-plated filters give a blue view, which cannot by changed. If you see a red surface in photos, it gives a red view, which cannot be changed. You will not be able to see a blue torch flame through this kind of dichroic filter.

    The advantages of a true color ADF in gas welding, can also apply to arc welding. Blue puddle auto-darken lenses and red auto-darken lenses are by far the most expensive kinds, but nothing prevents you from inserting a color film behind a true color ADF, to achieve these same expensive views.

    The best part about employing ADFs with colored polyester filters, is that you can cheaply buy a shade #3 visible light rating, while every one of these lenses limit UV and IR transmission to no more than is allowed in their highest rated dark states; that starts with shade #10, and goes all he way to shade #15 protection.

Update: Oubit Auto Darkening Welding Goggles are available through Amazon.com for $11; they are garbage, but they come with a 3-11 true-color auto-darken filter. I never recommend using an imported ADF for arc welding; for that, only trust your eyes to a very top of the line American made ADF. However a shade #3 clear state in a true-color ADF can be coupled with any color of acrylic sheet desired to make successful shade #4 or darker torch lenses.

2” x 4.25” auto-darken filters with shade #3 clear states can be dropped into torch goggles; the oldest models (lens face looks magenta (red-violet) in photos) provide a green view equal to a shade #3 athermal green welding lens, for between $8 and $10 through Amazon.com. Tru-color auto-darken filters (lens face looks gray or blue in photos) cost as little as $11. These filters can be coupled with colored theatrical films to create any desired color view in shade #4 and darker. Aiming matching colored LED dimmable floodlights at the work, can raise this view back up to shade #3. But how do you darken it? By starting with an ADF with a shade #4, or shade #5 clear state. Thus, you can fine tune your views between shade #3 and shade #6. This simple system gives complete eye safety with little bother.

    While the small window of a 2” x 4-1/4” ADF is perfectly adequate for shop work, a larger window is desirable for overhead work and working in confined spaces, in the field. Ambitious people can get a larger window by cutting apart a larger ADF and removing its three-part glass sandwich sheet (which contains a UV/IR interference layer); this is what you look through in its clear state (when the middle and rear polarization layers are not active). ADF clear state shades of #1.5, #2, #2.5, #3, #4, and #5, are available. Although any ADF with a clear state below shade #3 is only found in more expensive filters, at present (the lower the clear state the more expensive the ADF). Prices on ADFs are constantly reducing as “the latest thing”  becomes an older model. Prices for 2” x 4.25” true-color ADFs started at sixty dollars, in 2024; they dropped down as low as $11at Amazon.com in 2025. The viewing area on a 2” x 4-1/4” ADF is only 1-1/4” x 3-7/8” (its three-part glass sandwich measures 1.376” high by 3.976” long by 0.125” thick).    

    The second most common ADF size is now 4-1/2” x 5-1/4”; it was 3.54” high by 4.25” wide (or slightly different plastic body (cartridge) dimensions that would still fit in helmet openings meant for this ADF). This size is now an old design, which can be purchased through Amazon.com for as little as $5 in 3-11 green view filters, and as little as $11 for true-color 4-13 filters, because this size is considered dated.

    Some ADF cartridges can be easily popped open at their seams. Otherwise, the easiest way to free its UV/IR interference layer is to cut away its top section (where the all the electrical parts are)and pry the rear face of the plastic body away. All the inner workings are attached to the glass sandwich with soldered wire and nestled within a pocket on the front face; two or three gentle bends will break the solder, parting the glass away from all these electrical parts; its dimensions are 1.885” wide by 3.784” long.

    The plastic bodies are meant to fit within welding helmets designed to accept an ADF with approximate dimensions of 3.54” x 4.25”. My first ADF had a plastic body that was 4.314” long, and the second ADF’s body was 4.332” long. The glass sandwich is too small to work in 2” x 4-1/4” torch goggles, and the plastic body too wide and too long. You will need to cut the front face of the plastic down to just over width 2” wide and then hand sand it down to exactly 2”. Sanding off the ridge on the opposite edge will help in getting the part down to 2”. Sanding the ridges on its two ends will help reduce its length down to 4-1/4”.

    Next, place this spacer into the goggle’s recessed pocket. The glass sandwich will be set within this part, and trapped in proper position by it, only after it is placed within the goggles. You will end up with a smaller view than is provided by a standard 2” x4-1/4” lens, but far larger than you would get by simply dropping a  2” x 4-1/4” ADF into the goggles.

So why all this blah, blah, blah about slick light filters for torch goggles anyway, huh? Well, being a major picky-butt, I prefer silver brazing exterior parts unto forges, to screw mounting them. After all, you have already built or bought what you need to do the heating with.  Silver brazing is not about being a master torch mechanic. Its about setting the work up very carefully, and then strolling through your task; and part of that means being able to easily see what you're doing. People have been using various colored ANSI rated lenses to sneak a superior peak at their work for about four decades now. Yup, it's true. However those superior torch views can cost as much as two hundred bucks...I totally object to that!

Did I mention being a cheap-butt, too? 

Okay, Frosty. I sgave ya with two straight lines. I wanna good dig ought yous.

Again we are into Fall, and chilly winter is close ahead. Now is the time to seek answers to your questions about how to get on with building a nice warming gas forge for your garage or barn. For they who hesitate will shiver all through winter   

I don't know how I missed your July 21 post Mike. I have a pair of didymium glasses somewhere but they're pretty useless for anything but sodium yellow. Love my gold lens cover on my old supplied air welding helmet but but haven't welded anything toxic enough to need the helmet and a replacement shield lens cover is . . . Nevermind expensive. Loved it but holy moly. I found long ago that my eyes adjust to compensate for green tinted lenses just fine. Various types of hard solder each have a preferred temp but I can see it just fine after one test.  

So you challenge me with TWO straight lines eh? Okay, I'm equal to that my unequaled friend.

Frosty The Lucky.

 

The last time I used a gold surfaced passive green glass filter was about fifty years ago, when I was a welder at Boeing's Seattle plant. I still remember that it had a green view with a slightly blue tint; it was quite restful for high amperage welding; these filters had a clear glass front layer over the gold coated green glass. Such filters are still available, but are far from cheap!

So, what I am doing is pushing the envelope, to discover present limits of what can be done vision-wise by repurposing ADFs and other light filters, for redeployment in torch work. At present nearly all the good stuff is dedicated to arc welding, and torch welders can "take an old cold tater and wait".

Mikey don't like that 

I haven't done anything needing a tinted shield in several years but my old el cheapo auto darkening shield (ADF?) worked fine for anything from brazing, to arc welding, stick, mig and tig. It has a dial numbered from 0 - 12, the permanent tint is #2.

Frosty The Lucky.

2 hours ago, Frosty said:

the permanent tint is #2.

An ADF with a shade two clear state is a high class auto-darkening filter. About ten years back some of them were being offered at "introductory prices" on Amazon.com. Like a fool, I hesitated...and then they were suddenly gone, never to return 

Anyway, it sounds like you have a fine ADF. One of the things I mind about the very high priced name-brand ADFs being offered today is that their sellers seem to think three years use before they are ready for the trash can is a mark of quality. I must agree; its the mark of very poor quality in a highly over priced item.

I purchased one of the first ADFs on the market in a 3M welding helmet, a couple of years before Kathy retired me; it hung on the garage wall for a decade, and was still going fine when I gave it away along with all my welding machines. Since the surgeries, my eyes see well enough to weld again, but going back to the same old stuff sounds like a bore. Torch welding was always my favorite by far, and these days there is no boss to say "no, no; use the wire-feed"  

High class? It was literally an el-cheapo from the local real hardware store and they were everywhere, different brands and prices. The "pro" shields were a couple hundred bucks.

I cringe at what passes for quality these past few years. Seems there aren't trained personnel building things anymore, look how often jet liners fall out of the sky or just catch fire. IIRC there's been something like 2+ a month this year.

I always liked gas welding, less demanding than Tig but the same. Unfortunately an oxy propane torch isn't worth spit welding steel no matter what the maker says. So, I have my little GMAW and the Lincoln 350amp welder generator though it's been so long it may not start. 

Frosty The Lucky.