Latticino

What mix did you use to insulate the inside of your soup can? Unless high temperature castable insulation of some sort be careful what you mount the forge on and how close you set your burner to the forge port.

How long does the compressor run at night? If a single time, or widely separated, could just be stored air temperature dropping and losing just enough pressure to startup unit. Have you checked for valve and fitting leaks at your indoor storage tank as well? Might want to see if you can increase the deadband in your compressor controls so it can drop a reasonable percentage before kicking on. Another remediation option would be to put a timeclock on the power to the compressor, though if you wanted to work off hours you might want to add a HOA switch for override as well.

Completely understand. I was replying to Frosty on this regarding his custom "fibrous brick" project. Please note that the rating for the fiber board product is 1400 deg. C, approximately the same as the blanket often used for a low mass forge insulating barrier. I still strongly recommend an inner protective coating as well as a burner block and/or flame "strike plate" (for the wall opposite the flame) made of materials that will resist the 3,000+ deg. F flame temperature. I typically use Mizzou for this. I have posted elsewhere that I am definitely in favor of a multi layer forge lining (Kastolite or equal interior and wrapping of refractory blanket) that you suggested. I also have used an inner lining of high density refractory at times (inside the Kastolite), but only for equipment that will not thermal cycle often, or rapidly, as the two castables have markedly different thermal expansion ratios and one of the two will inevitably crack during the cycle if it is too rapid. I always wanted to experiment with putting a layer of blanket in between the two to see how that worked, but haven't had a chance to do so to date.

I'm sure you are aware that Kaowool, or a similar high temperature glass fiber material, is also available in board form. It is fairly expensive relative to the blanket, but rather than casting it yourself you might want to look into using that. Board available up to 2" thickness from this manufacturer: http://www.morganthermalceramics.com/products/refractory-ceramic-fibre-rcf/board-products. Not as "structural" as brick, though I suppose you could cut out 2" thick rectangular sections and stack them similarly to your brick design. I'd still coat them with a rigidizer of some sort.

I would use Mizzou for that type of burner. It is rated for 3,000 deg. F.

Mizzou is a high density, high temperature castable with fair resistance to molten glass (flux). Refractory castables with higher percentages of alumina and/or zirconia have better flux resistance. It has very little insulating value (close to that of concrete). As you noted, it is a good choice for forge liners, if you are looking for a high thermal mass forge (and plan on backing it with some kind of high temperature insulating material), and ribbon burners. It is more economical than the equivalent high alumina refractory castables and in my experience a bit less prone to thermal shock. It also has a coarser surface finish than the high alumina castables, which can be an issue with ribbon burner ports. Additional info here: http://supplies.foundryservice.com/item/castable-refractories/dense-castables/mizzou Kastolite 3000 is a castable insulation which can be used for a forge liner as well without specific requirement for backing insulation. It is still higher mass and less insulating value than refractory blanket insulation, so you will need more thickness to get an equivalent insulating lining. As far as I know, Kastolite is not very resistant to flux, so some kind of inner protection, at least at the forge base, may be required. A composite lining of an inner wall of 2-3" Kastolite wrapped with an inch of blanket, and a forge floor of bubble alumina, Mizzou, or Greencast 97 might be the best of both worlds, though it will certainly heat more slowly than a blanket insulated forge with a thin refractory liner. Additional info here: http://supplies.foundryservice.com/item/castable-refractories/insulating-castables/kaolite-3000-kast-olite-30-li

Glad to help. For what it is worth, I used Giberson burner heads on blown, low pressure, natural gas burner assemblies for 10+ years. They are quiet and supply a nice soft, hot flame. Have to be careful regarding thermal shock, but that is the case for any type of refractory.

The classic Ransome industrial NA burner has a tapered mixing chamber, as described. These are used extensively in the glass and ceramics world for firing furnaces and kilns. One of the best ways to use same is with a Giberson style cast high alumina refractory burner nozzle. These are round, or rectangular in cross-section and have multiple small openings for the mixture to exit the burner (remind you of anything?). You can check them out on this site: http://www.joppaglass.com/burner/mini_square.html. Note that he even has a small forge design to go along with his burner/burner tip assembly.

Actually typical bathroom exhaust fans are designed to be ducted, just not with a whole lot of static pressure. Typical bathroom exhaust fans run in the 50-140 CFM range and between 0.1 and 0.25 inches Water Gage of static pressure. This pressure is fine for the typical backdraft damper and 20' of 6" diameter duct that is run from a toilet. However, though a good bathroom exhaust fan is rated well for the high humidity bath exhaust it is not at all well suited for the heat, ash and sparks that might arise in a solid fuel forge exhaust stack. Many bath fans have plastic components, including impellers. I would never recommend using a bathroom cabinet fan for forge exhaust. You might be able to use one as a forge air source, but there are many better options available.

I have a "low pressure" natural gas forced air forge in my shop which works quite well. I am using an industrial burner with high quality mixer, ventauri chamber for expansion, high pressure blower, and zero pressure regulator. I've built several pieces of equipment with this kind of burner assembly, and it works just fine, but might not be the easiest system to configure (I got mine for free from a glass studio that was being upgraded - everything was in the dumpster!). Forced air systems are a lot easier to use as far as dealing with backpressure of forge configurations as well as varying the proportion of the gas air mixture to change the forge atmosphere. There are safety considerations though, and your local codes may require either a gas shutoff interlock with UV sensors for flame proofing and/or airflow sensors to ensure the blower is running. Without these I would not leave a blown system unattended. I have seen sketches for home built NG burners with forced air. They are essentially the same as propane/forced air units with larger gas orifices and gas feed connections. As Tim states it is not really feasible to use low pressure natural gas in a naturally aspirated burner for a forge. The pressure isn't sufficient to create the velocity needed to induce the right amount of air. Blown burners don't need this velocity, but you will be surprised at the gas pipe diameter needed to move the quantities of gas required for forging in a reasonable size enclosure. These also work great with ribbon or Giberson style burner heads which give you a much quieter and more distributed flame.

As usual our local curmudgeons are trying to gently steer you along in a safer and more practical direction. Casting metal is very dangerous. Get some hands on assistance and training from someone who has actually done it successfully for a couple of years (and still has all their parts intact). Training by watching YouTube does not qualify. As far as crucibles go, how are you going to cast a crucible if you don't already have a crucible to heat the metal up in? Kind of horse before the cart there. Not to mention, that as Thomas said, non-metallic crucibles are a better choice. Crucibles are a consumable in a foundry in any case, so a cheaper, time tested alternative is a better choice. Suggest you Google search graphite crucibles for info on suppliers and crucible types.

As I mentioned in another post on this forum the same thickness of high temperature glass fiber blanket is around 10 times better insulating material than a plaster/sand mix from what I could find regarding these materials. Even though there are certainly some losses due to radiation out the open door and convection of the heated combustion byproduct gasses, this is a rather significant difference. This is not even taking into account the thermal mass of the plaster/sand mix which will take a lot of time to heat up every time you fire the forge up. As Vaughn correctly states, using this material for a gas forge liner is a false economy, unless you get free fuel... I'm in process of building a quick paint can forge to use as a demo for my blacksmithing group this weekend. I plan to use a scaled down Frosty T burner (1/2" dia. burner tube with a 0.23 MIG tip). This forge will be insulated with Kaowool and will have both front and back door openings. If successful I will post results, but I fully expect it to get up to forging temperatures easily.

Amazing result for a first effort. Love the activity in the Hamon. A coil spring? Seriously? Did you forge weld it to make up the required billet width? I could see this from a leaf spring, but the only car coil springs I've seen were 3/4" dia. max and would be a real chore to spread out this far and keep enough thickness for the spine. What was your quench media? How did you accomplish tempering? I'm sure some of the experts will have suggestions as regards your grinding and polishing, particularly as regards the tip geometry, but all in all I would call this a major success. How does she cut? Sorry for all the questions, but this is exciting work.

I don't have a tremendous amount of experience building solid fuel forges. In my experience of using same they don't need a lot in terms of "enclosures", just something to consolidate the fuel in a location where the forced air can be directed to burn it as required (not to mention drain away the ash produced). I would certainly experiment, but believe that you are overthinking your forge design, and possibly combining it with flue design (which is a whole different kettle of worms). Might want to try building a successful design before you set out to reinvent the wheel.

Please remember that digital pictures and video don't give anything like accurate colors for heated steel. If you look carefully, or even experiment yourself, you will notice that the steel being forged in most amateur videos looks like it is much hotter than required (often white hot). This is due to the camera sensing elements, not the actual heat of the material. As this is only the basin for holding solid fuel, insulating characteristics are not necessarily critical as regards potential for forging, just for keeping the body of your forge from burning the surroundings and the rest of your assembly (including the PVC, whose vapors on burning are nasty). Insulating properties for materials can be calculated for known material thickness, enclosure geometry and interior and exterior temperatures. Of course losses from various types of heat sources must also be taken into account (i.e. radiant losses from doors and convective heat losses from transfer of products of combustion). Probably the best way to test materials would be using electric heating coils (where an enclosure can be fully sealed). I'll bet ASTM has a standard for this (ASTM C177 or C518). Please note that the thermal conductivities of some of the products you have been discussing are as follows: Plaster/sand mix: 0.71 W/(m deg K) per the Engineer's Toolbox (which I have found to be rather accurate), Insulating fiber blanket: 0.07 W/(m deg K) per manufacturers data. Note that the latter is 10 times better insulator at a more elevated temperature

Mixing it with sand will certainly help with it's refractory properties, but I doubt greatly it does anything for it's insulating capabilities. Two things to remember from that DIY video. First, there is no indication of how much fuel needs to get dumped into the melting furnace, so efficiency (which is pretty directly related to insulating capacity) is not spelled out. The other is that aluminum melts at around 1,250 deg. F and forging temperatures can reach twice that. I'd be really careful to put some kind of non-flammable and preferably insulating material between this proposed enclosure and any table support (unless that table is itself quite heat resistant). Of course your bricks will help with this, but be aware that normal bricks and concrete block are not rated for this kind of temperature either. It might be prudent to actually build one of these before recommending a design to all and sundry. I'd say this material would be fine for the basin of a solid fuel forge. After all, folks use raw clay mixed with a variety of additives (including sand) for that as well. If it burns thru you can just break it out and replace it cheaply. Not sure how this mix will resist flux, of course, but that may not be a big concern for you. Finally, here is some additional information that may help you in your cheap refractory formula search. Admittedly it isn't on You Tube, but Anvilfire has some very reputable contributors, and this one appears to have actual forge building experience: Good luck Anvilfire does not allow hotlinks from it's site

Sketch is unclear, some annotation would probably help. Typically when you try to make a piece of equipment do everything, you end up with something that does nothing particularly well. Not sure what you are trying to accomplish here, but the gas forge option configuration looks to be incredibly inefficient (unless you are planning on injecting your propane into a solid fuel system for some kind of extra "boost". Probably not a good or safe idea). Size and materials of construction aren't well spelled out, but while a hard fire brick forge will be great for a solid fuel forge, it will be pretty awful for a gas forge. I've never built a foundry, but can't imagine it would be any better for that. Your solid fuel forge will want a chimney for smoke control at the top. This will be deadly in terms of energy for a gas forge/glass furnace... If you go with a side draft hood it will need to be removed and the opening plugged somewhat when converting modes. As far as glassblowing, speaking as a former professional glass blower who built equipment for several studios, I have no idea what you expect to use this piece of equipment for. Are you expecting to make it into a sort of combined glass furnace and glory hole? Gas fired annealer? Slumping oven? Glass equipment has different constraints from metal forges/foundries. For one thing the furnace has to run 24/7, so safety equipment is a must. From your sketch I expect you haven't got a clue regarding this. Materials of construction should be able to withstand more constant contact with molten glass (rather than just periodic flux spatters), one of the most corrosive materials known. You will most likely need a larger propane tank for running glass equipment as well (a couple of 20 gal barbeque tanks won't cut it at all). The shells for the various types of forges/furnaces are not all that expensive, and it would probably be advisable to build one for each type of usage you are contemplating. Burner assemblies aren't that much more (unless you are contemplating getting an industrial one, which given the level of your design abilities at this point I would recommend). You certainly might be able to share the burner assembly between different equipment, but again you are looking at compromises that will likely make each system inefficient. Suggest you do some more research into forge, furnace, and foundry design. There is a lot of good literature out there (for glass eqt. I recommend Henry Halem's and Dudley Giberson's books), but be careful what you glean from the internet (including this, I guess...)

Know that the OP is now offline and will not benefit. Also am aware how ingenious and full of himself he came off in his first post. Is description of his "exotic" handle was poor, but it did have an aspect that I think has been missed that made it fairly unique (mostly because it is a design that I think was pretty awful). The wound handle is wrapped around a hollow core, like a spring. Not sure if he understood that a 1/4" diameter wire spring would flex, which certainly wouldn't be good for a knife handle.

Nice score. She looks good to go to me. Just get a stump or build a stand and get hammering.

Brazeal style hot cuts are designed to friction fit into the hardy hole (if that is what you mean by brazenly). If you add a shoulder it becomes a more conventional hot cut. With that type the shoulder needs to be very substantial to support all the weight of the hammer striking during the cutting operation. There are a number of different ways to form this shoulder depending on the stock size you have and the tools you have to work with. Anything from forge welding a collar, or upsetting the center section and necking down either side (as it appears you have tried to do), to arc welding a hardy post onto a shouldered cutting edge. You can even fuller down two sides of a thick flat leaf spring to form a shoulder that fits into our hardy then put an edge on the opposite side (hot cut goes into the hardy hole on a diagonal). You are doing a good job working with such heavy stock, but if you decide to keep on this way remember to let the steel soak for a while so that the inside gets hot as well as the surface. Otherwise it is almost impossible to avoid the fish mouth syndrome. This size stock forging typically responds better to blows with a heavy hammer. A 2 lb. hammer will be kind of tough going unless you are very hot. You may want to wait till you have a striker handy and can work with a heavier hammer. Once the blade edge is thinned out further you will be able to clean things up with your 2 lb forging hammer. Good luck.

You could possibly offset the stem over using light hammer blows at the joint, but it appears that there is a crack starting, so I would recommend starting over. Typically I make leaves a lot thinner, drawing out the center further with a cross peen. This is good work for a second leaf. Try making a dozen or so and see how your work improves. This is good practice for a lot of other blacksmithing processes. One trick I sometimes use is after the basic shaping is complete laying the leaf lengthwise along a fairly sharp edge on the anvil and using half face blows to emphasize the stem projection into the body of the leaf (done on each half of the leaf with the stem extension resting right at the edge of the anvil).

If a politician dropped by my shop and started to talk to me I'd probably show them the business end of the hot steel

Take a look at Thomas Latane's work. He does stake anvils, though not quite as elaborate as this one. He also does the gothic chiseled style faces, though not in those locations, as far as I know (yet). Hope he sees this image and it inspires him. With the right team he surely could do this. That is a superb stake anvil though. Can see why it is in a castle.

Air from the side will be effective, though the abrupt elbow it takes will make it less effective than if it entered the "typical" forced draft burner fashion, due to the pressure loss associated with the rapid change in direction of air. If your blower pushes enough static to overcome this, it should be fine. You may want to replace your gas nozzle with a larger one to take advantage of the increased output your new burner can be capable of. I believe that it is a misconception that a blown burner is intrinsically more gas efficient than a comparable naturally aspirated burner. However, with the same gas pressure of propane available, and the ability to replace a gas nozzle so that more gas is available at that pressure, you can almost always get more heat from the blown burner. You also get a bit of grace on the size of the forge doors and the outlet of the burner itself, as the burner pushes the flame out at increased overall pressure. You also need to know how to properly tune and operate this type of burner. It isn't all that hard, actually a bit easier than a NA burner as far as I'm concerned, but it is different. Cross post with Thomas. Totally agree with all he has said, but as I noted, with the same high pressure propane (typically modulated down a bit using your regulator) and a blower, the burner will be capable of burning hotter (especially if you increase the nozzle size at the same time).

Unabashedly functional. I really like this one.