Latticino

Frosty, I think that is a great idea. Too bad I'm getting it too late to change everyone else's plans . Agree, it is tough living out in the back beyond. I'm sure lucky with monthly hammer-ins only a 20 minute drive away and two additional ones only 2 or 3 hours away as well (not to mention four different good quality craft schools that teach blacksmithing within a days drive also).

I'm bummed that I will have to miss it this year. Previously scheduled niece's engagement party out of town. Too bad they didn't announce it sooner as I would have passed on the party.

Possibly, that is why I recommended you draw out and fold several times to refine the billet, then just use it as a San Mai over good stock that will make your blade "monolithic". Could make for an interesting pattern. Now that I better understand the photo progression that may not be worth doing. The second photo shows some very deep cracks.

Agreed, particularly the tennon and rivet on the "end cap".

All the forges and furnaces I've made had flares or flame retention outlets shaped from cast refractory until my most recent one (which has a commercial SS flame retention outlet that I picked up out of the trash). I usually defaulted to the 12 degree angle cone for mine, starting at the forge skin and progressing to the forge interior. My take on it is that you want the air/gas mixture to be as large as possible without going overly turbulent. Larger because that slows down the mixture velocity (slower, shorter flame). I like some sort of transition between the forge interior and the mixing tube diameter as it makes it a bit easier to tune the burner (locate the flame front outside of the mixing tube). Each to their own though. Many forges operate perfectly well without a flare.

I'm confused regarding the progression of photos shown. Is your number 1 the top photo? If so, how did it get shorter in photo #2? Looks to me as if you were too aggressive in how far you compacted it for each heat. Smaller "bites" at that high yellow/white heat. Also I would recommend keeping the billet at welding heat, or close to it, during the initial compression you do out of the cannister (at least till the billet is down to the nominal 3/8" thickness and well compacted). I wouldn't discard your first effort. You might be able to layer it up and forge weld it again, then use the final product as San-Mai with a core of HC steel to ensure the edge is good.

Very well put.

Looking pretty good, though a little long. I made my current forge out of a similar tank, but cut around 5" of length off and wish I had removed more. Keep us posted on how it works for you.

No, if you don't need to fully open the gate valve for the air during full fire your pressure is fine. I have no problem with necking down the mixer outlet before introducing into the forge, however there are consequences. With a smaller outlet the air/gas mixture will be flowing faster for the same quantity flowrate (BTU output directly related to that flowrate). Faster flow means a different flame front location relative to the output for each forge interior temperature. Too fast and it will lift off the front of the tube and blow out (you also may get a "faster", longer flame which can be a problem for certain forge configurations). Too slow and it will burn back into the mixing tube and heat it up (or the air/gas mixture won't flow enough to cool the mixing tube from the radiant heat from the forge, if done once the forge is up to temperature). Remember that flame speed is also related to forge interior temperature, so it needs to be different for each, a balancing act. If your forge is only losing combustion under low fire when warming up and you try to block the doors, that is likely a product of not having enough pressure to push the products of combustion out of the forge interior (ever try to heat the interior of a can with a propane torch?). You are choking off the flame. Simple answer is to not close the doors until your forge gets up to temperature and you increase the air/gas to more usable levels. You will probably be able to block off the door part way. Door baffles are just doors that stand a little way off the door opening (parallel, but 1/2" to 1" away from the face). This addresses radiant losses, but allows relatively free flow of combustion products.

Your blower looks like one that is optimized for flowrate rather than pressure, so it may not be capable of putting out the required air pressure at the outlet of the burner. Not an uncommon problem for those who select a squirrel cage blower. Flame doesn't look that bad to me in the final video. I can't tell from the photos or videos whether you are inducing secondary air at the burner nozzle entry to the forge or not. This secondary air would be very subject to variations in backpressure from the closing of the forge doors. If you gradually close the doors, does the flame turn more yellow before it goes out? That would be an indication. If the blower doesn't develop enough pressure to provide the correct mixture a the temperatures you are looking for (BTU output from the air/gas mix) you will either need to get a better on (axial rather than squirrel cage) or drastically reduce the mixing tube line length and remove elbows. Is the air valve open all the way during high fire? Note: it is fairly common to have to keep a burner at a lower fire when the forge warms up. This has to do with the flame front speed vs the air/gas mixture flowrate at the outlet. The issue with blocking the door and having the flame go out is different. In my blown forge I can just about completely shut the door and make do with a 1/4" gap all the way around. However I use an axial centrifugal blower optimized for more pressure and it has a 1/2 HP motor.

Sorry folks, down with COVID so not as on top of things as usual. All advice here has been very good to date. I expect the original hookup was for residential pressure natural gas, which is what I run here at home as well, based on the apparent size of the gas feed. I've not converted one to high pressure propane (or wanted to as NG is so much more convenient), but it shouldn't be that hard. I would definitely keep the fan assist configuration, but you may want to neck down the gas feed to something like 1/2" with a 1/4" orifice to avoid having a flame thrower if you regulator fails for some unknown reason (not critical, but a good safety measure). Of course doors, proper rigidizing and coating with a refractory are also a good idea, as is a good quality gas regulator. The other safety recommendation I have is to install a gas rated solenoid valve on your propane feed that is connected tot he same circuit as the fan. Not quite as good as a flow or pressure switch, but if the power to the fan shuts down it will shut off the gas. The chamber size is a little small in diameter for a typical fully developed flame, but having a multi-outlet burner should help with that (shorter, well spread flame). You will have all the typical issues with multi port burners (characteristic optimal operating range and potential for preignition in the mixing chamber during turn-down), but these are more easily dealt with in a fan assisted configuration IMHO. I'd be careful with the fan speed control, as conventional ones tend to burn out synchronous motors, and I think that Dayton may have such. The blower may be a little small for the forge size in NG configuration, but could be fine with propane. As Mike and Thomas mentioned you get a different BTU output from propane than NG and the quantity of air needed is different as well. Not firing on all cylinders now, so not going to do the stoichiometric combustion calculations, but you may need to adjust the number of outlets to get a good burn at the temperatures you are looking for. Most likely fill some if you have a problem with preignition once the forge is up to temperature (all a matter of matching the flame front location to the temperature of the forge interior, as I have written about in the past). Note: if you hear ANY pop-back, close off the gas immediately, but keep the air running to cool the burner. After a minute or so you can usually turn the gas back on. Floor and burner look to me to have been cast from Mizzou or some similar refractory. Should be fine for flame and flux contact, but the floor may bleed a little heat.

+1 on used ceramic kilns. I see them all the time and it is pretty easy to fix one up if not functioning if the bones are there.

Sorry to have somehow missed this whole thread and not contributed earlier. Lots to process. To start, let me correct some misunderstandings. While I did get a job offer from Corning to work there as an engineer on their process line right out of undergrad, I didn't take that offer. I wanted to stay in the Boston area, and yes there was a woman involved. Years later I got into glassblowing full time, received an MFA from the School for American Craftsmen at RIT, and ran my own glass studio for around 10 years. I have also taken a handful of classes at the Corning Studio with some glass masters, but I was never employed there. I am far from a glass historian, but I do have a bit of practical experience with both glass and steel, mostly separately. I've blown glass with both steel and stainless steel pipes, and the latter are significantly easier to use. Modern glassblowing pipes are usually tubes with a spun, swaged or plastic insert mouthpiece and a welded, drilled, bar stock end for picking up glass. This helps with both heat transfer and weight. The “business end” of the pipe needs to stay hot so thermal shock doesn’t spall the glass right off the end of the pipe, so in use we typically preheat that end to just under red hot before attempting to “gather” glass from the furnace, and keep it at elevated temperatures during the entire process. Needless to say it is important for the end you are holding and blowing into to be cooler. The extra thermal mass at the business end stays hot longer. Thermal shock at the glass/metal interface in this case is a product of the different thermal expansion rates of glass and metal. I’d have to check to be sure, but I can say from experience that copper bonds better to molten soda/lime/silica glass (and causes less thermal stress in the glass after annealing) than steel. Of course each glass formula has slightly different thermal characteristics. In my experience encapsulating steel within molten glass is a recipe for thermal shock and eventual cracking, sometimes violently, of the glass. Of course I have mostly worked with “hard” soda/lime/silica glass, not “soft” borosilicate glass (like torch workers). These days there are different custom glass formulas that bond better with steel, but I haven’t any experience with them. I know that shortly before he closed up his shop, Al Paley was conducting same fairly extensive experiments with Corning to come up with a formula that would be more compatible with his forgings. Side note: I did blow a handful of glass lamp shades for his shop back in the day, but these were cold connected. Please note that no matter how good a glass/steel bond looks it can be very subject to thermal shock down the road. With the glass surrounded by steel it may be better than having the steel surrounded by glass, but in either case very slow annealing after the glass casting would be prudent (8+ hours down from 900 deg. F to room temperature for glass thickness around ¼” is what I remember; a computer controlled annealing oven is a good idea). I’d also remove any sharp corners from the steel that impact on the glass. Ideally I would do a check for stress in the glass after a test full process was done using a polariscope, but those work best with clear glass.

Not only that, but the dispersion of CO will most likely vary quite a bit depending on the temperature of the exhaust stream where it is being created. In the experiment cited it was unclear at what temperature the CO was introduced to the space, but most likely was close to or below room temperature. My expectations for CO generated by our forges it that it would rise rapidly to the shop peak due to the buoyancy effect, then diffuse downwards as the exhaust airstream cools. In many cases this would make it more insidious and potentially dangerous. Still this is only a theory.

Books, articles and videos are all helpful (once you know what you are looking for), but nothing beats taking an in person class. I would definitely look into that before spending anything on tools or equipment. Noise on a small lot is certainly a concern, as is building a forge in a structure attached to your home. Ventilation, code and safety issues will need consideration. Half of a 3 car garage is a great size for a home forge, but whatever else is stored there will get dirty. As far as books go, I would recommend the "Backyard Blacksmith" for beginning general forging and Jim Hrisoulas's books for sword smithing (though you have a long way to go before being ready for the latter). There are also some great articles on this site regarding these topics, but you may have to dig to get the info you want.

I recommend you get Jim Batson's book on building hydraulic presses. It will answer a lot of your questions. Unless you are very good at scrounging expect to spend over $1,500 for the materials and equipment you will need for construction, not including your time and consumables. As the guys have mentioned excellent welding skills are required. One consideration is to be sure you actually need a hydraulic press. There are other options, depending on what you plan on forging. Unlike what you have seen on Forged in Fire, the vast majority of smiths have never used a hydraulic press, much less owned one. I'm not saying they aren't a nice tool, and I wouldn't mind owning one, but they are also expensive, need a significant power source to run, and can be dangerous for the novice user.

Have one and quench once color doesn't show, IF I need to quench. Ideally you should work the drift pretty hot so it doesn't suck the heat out of your stock. I find these really work a bit better as mandrels rather than drifts, but I weld my sockets typically so need to worry about "popping" the weld.

Cross posted with Thomas. Great minds... Hope someone comes up with a better solution, but my advice would be to drill a small hole at the end of the crack to stop it progressing further and braze the rest of it shut. As I understand it, welding cast iron is not a simple process. Did you drop it or hit it with something?

Note: While a kiln wash like Plistix may help with IR re-radiation and a bit of flux resistance, it is unlikely to add any significant strength to the ceramic fiber board walls. This is the major advantage to adding a 1/2" - 3/4" thick layer of cast refractory insulation like the Kastolite 30. In my experience ceramic fiberboard does not stand up at all well to multiple thermal cycles, and sags at higher temperatures depending on the unsupported span. I hope the kiln wash does what you need, but it isn't the direction I would go for a durable forge skin.

Been thinking about trying to market hawks to that crew as well, though might be tough to meet the price point of some commercial suppliers. In my limited experience with throwing I find that I agree with you on the typical point of impact for the top half of the edge. I actually like a bit of an upswept point there for good penetration on impact (see Francisca axes), but a flat top works well also.

Wish I could take credit for that, but I learned it from James Austin

That Wilton Bullet is nice (and I believe fairly collectable). Around here they go for a good dollar.

Cool, a tabletop camelback. Thanks for sharing that's a new one for me.

For power hammers think greater force, lower BPM, lower force, greater BPM. Take a look at the Anyang USA site for details. I have a "34 lb" that hits at 250 BPM when all is running properly; their "178 lb" is only rated for 205 BPM. What I've seen work well is a combination hydraulic press and rolling mill using a hydraulic motor to produce low RPM and high torque...

Yes your forge is likely on the order of twice the size you need right now. I'm a fan of putting a rather healthy layer (3/4" thick minimum) of high alumina castable refractory insulation (like the Kastolite 30 that Glen sells in the IFI store) as an internal protective wall in my forges, but I have some significant lung scarring from exposure to untreated ceramic blanket during my years as a glassblower. Rigidizer will keep down the bulk of the fibers, but it is an extremely thin topcoat layer, if applied correctly, and can be easily damaged (not to mention dissolved by flux). The castable refractory adds some thermal mass, so your forge will heat slower, but also acts as a bit of a "thermal battery" when you put a mass of cold steel into the forge (like a hammer head blank). Mixed and applied correctly it is a very durable surface and will also resist molten flux to a great degree.