Buzzkill

This is where it can get a little bit challenging. You really don't want the flames entering the forge chamber from the side at floor level where they will hit your stock before combustion is complete. You, in my opinion at least, want to install the burner so that the flames enter the forge near the apex of the forge chamber and have a little room for combustion to complete before impinging on the lining. Based on your pictures I'm guesstimating you have about 2.5" from the mixing tube to the business edge of the burner head. Unfortunately this means the preferred mounting spot is such that your mixing tube will hit the side of the shell before the burner head gets as deep into the forge body as would be ideal. Of course you can flip the burner 180 degrees so that the T is sticking up above the forge, but then you need to build some support for the mixing tube to help hold the burner in place, and it also increases the likelihood of recycling exhaust gases. I prefer the side mount near the top to encourage swirling of gases in the forge, but I think this issue is why some people mount ribbon burners in the top of the forge body and point the flames straight down. As with most things, there are advantages and disadvantages to the various options here.

Not at all as far as I can tell. Looks quite good. There is a very small design feature I did a bit differently and I can't tell you for sure if it really matters. Around your front opening you have a thicker portion (I assume you did that for more durability at the opening) which effectively makes a lip going up into the insulation. What I did on both ends was the same principle, but I put the lip inside the forge chamber. My reasoning for this (again I can't say for sure is correct) is it would help keep the flame in the center of the forge chamber a little bit longer and therefore transfer more heat to the lining before exiting. Of course I have most of the front and rear openings closed off/restricted while in use, but I'm hoping that the swirling gases try to "hug" the shape of the lining and will be slowed a little bit by having to go over the lip to get out of the forge. Regardless, I think you're going to be happy with what you have when you get done with it.

Is it the regulator or the burner that sat out in the elements for a couple years? Either way, one of the quickest and easiest things to do is ensure that nothing has restricted the opening of the mig tip in your burner. Debris or tiny critters can restrict or deflect the gas stream. That can also produce the sputtering flame that burns inside the mixing tube. If your regulator has been compromised it could be part of the issue as well. When we were young Dad always told us "Check the easy things first."

I did one similar to this. I'd have to find my notes or pull the burner to do a hole count, but I think it was around 160 holes at 1/8" diameter. I used bamboo skewers and petroleum jelly for the holes. I sifted Kastolite 30 and used that for the refractory. My memory isn't what it used to be, but I think I ended up using a schedule 80 3/4" pipe nipple with a .023 mig tip to get the fuel to air ratio where I wanted it. I'm still using that setup, so I can check it out and report back if I remember. I'm pleased with the overall performance of the burner. Although I sometimes do get some harmonic howling for a few minutes while it heats up, in use it's generally whisper quiet and provides a great even heat in the forge. The operational range is excellent as well. I can go from less than 1 psi showing on the gauge to over 20 psi. If I've been operating at forge welding temps for a while and try to go back down under 1 psi it will experience some burn back into the plenum, but that's not surprising. I hope yours works out as well. I'm certainly interested to learn how it performs for you after you get a few hours on it. I've also built the style forge you refer to. I couldn't tell if you are planning to do a floor mount burner or mount it in the shell. Both work well, but I found I prefer the shell mount burner location due to the amount of floor space I had to sacrifice with the floor mounted orientation. You may find that half a helium tank is a bit small for that burner. Unless you will only ever need to heat straight pieces you may want a little more diameter to work with. If I recall correctly I ended up building my latest one with about 9 inches width at the floor and about 4 inches at the apex. That gives me a little wiggle room for oddly shaped pieces. Unless you are going to do long twists you can keep the length to 8 or 9 inches to keep the volume down where a single 3/4" fed burner is enough for forge welding. Just my 2 cents, but it looks like your burner should do well with a little tweaking. I'd try the next lower size mig tip as a first step if it were me.

That would be my working assumption unless there was other evidence to change my mind.

It could be cracks or it could be other things as well. If the surface of the steel was brought to an even finish then it probably was cracks. If there were some deeper scratches from grinding or something else it could appear as cracks. This may be a good opportunity to learn a little. You can grind/sand (preferably perpendicular to the lines) where you see what looks like cracks until the darker lines you see disappear and then etch again. If they were just grinding lines or surface cracks then they probably will not show up again in the same location and orientation. If they are truly cracks then they will probably show up again where you saw them originally.

I delaminated the blanket so that the strips were less than half an inch thick. I soaked them with rigidizer before putting them in place, partially to reduce the risk of airborne fibers. I placed the forge body on the strips while they were still wet and fired up the forge. While probably unnecessary, this essentially fused the floor and top shell pieces together. I've had to take it apart once since then and the blanket gasket pulled apart in the middle. So, ultimately I'd say the advantages of using rigidizer are a reduction in the likelihood of airborne fibers (although it's not a big risk due to the small amount directly exposed to flames) and probably a slightly better seal than the blanket alone. I should probably also mention that when I coated the interior of the forge chamber with a kiln wash the small amount of exposed blanket received a coating of kiln wash as well. Not at all. I'm happy with the 2 piece constuction overall. I was just letting you know a couple small issues to consider. As far as I'm concerned it's the best design I've used so far. If done right this could work well. It would certainly cut down on the amount of castable refractory needed for the floor. I may give it a shot when I have to rebuild my forge the next time.

I have done this. There are a couple things to consider. The thicker you make the floor, the more it is a heat sink. The result is more time required to heat up the forge and a longer cool down time. A half inch isn't too bad, but it becomes much more noticeable if you go thicker. Each forge/burner combination is different so it's hard to compare to what other people have done, but I'm still able to go from a cold forge to forge welding temperature in about 20 minutes with a cast floor as you describe and a "D" shape overall. However, I'm using a ribbon burner and the volume of my forge is a little larger than yours. The other issue I had was getting a good fit between the upper forge body and the floor. It seems like it should be easy, but if you are trying to avoid having any gaps at all it is not so simple. I ended up using strips of some extra kaowool, which I treated with rigidizer, as a gasket between the floor and the forge body. That has worked well so far.

Unless you are planning to make crucible steel I don't think you need to reach temperatures anywhere near that hot. One of the highest temperature tasks we do is forge welding, and that can be achieved around 1200 to 1250 degrees C in most cases.

I built a forge similar to your last sketch with a ribbon burner. The reality is that I sacrificed about a third of the floor space to install the ribbon burner in that orientation. However, it did perform well and provided good even heat throughout the forge that way. Since then I built a different forge with the ribbon burner mounted on the side. It was more difficult to build and doesn't perform quite as well as the floor mounted burner in my opinion, but I prefer the extra floor space.

I thought perhaps he was smashed on some potent corn squeezins. That would certainly explain the serpentine pattern of locomotion.

Oh come on now. How can a smashed snake get the mail?

IMO an auto switch system would not be worth the hassle/headache. Although unnecessary, my setup has a gauge for the tank pressure as well as one for the burner feed pressure. When I notice the tank pressure dropping down below 50 psi I have about 20 minutes left before needing to switch tanks. Typically I can swap tanks and start up again while the forge is still glowing and will ignite the propane just by turning it back on. Your mileage may vary. I'm a keep it simple kind of guy, so adding other things that can go wrong but don't significantly improve functionality (in my opinion) is a step backwards. You do you though.

What could go wrong? Several decades ago when I was in the Army I was told about an attempt at automating "friend or foe" vehicle recognition. They had numerous photos of different vehicles which they "fed" to the program to train it. After a while the program was 100% accurate with the training photos. However, once they moved beyond that it was wildly inaccurate. Long story short, the training photos for one set of vehicles were all taken on sunny days and the other set was taken on overcast days. Rather than the subtleties of vehicle shapes, the program keyed in on the weather conditions. Technically there was nothing wrong with the program. It found the most reliable information to determine friend or foe. The problem was the input. The outcome of these types of systems are still largely dependent on how we design them and what we "feed" them. This will probably remain true until/unless an AI can rewrite its own source code. Then we open a whole new can of worms.

The main reason for me is I've run out of things to say. Your work always has a simple elegance which would make it look as at home in a display box as in a working man's hand. Regardless of whether I comment or not, I always look forward to your latest work.

I recommend the following link if you're obsessed with wootz. You may want a plastic cover for your keyboard to keep the drool off the keys: https://www.iforgeiron.com/topic/53084-first-crucible-steel-run-and-forging/

I'm not sure what you meant by "vertically swinging door." The door on the professional setups stays in the same orientation when opened but moves away from the body of the oven and upwards. That way the hot inner surface of the door isn't a hazard to you while loading or removing objects. I'm guessing that's probably what you were thinking, but thought I'd bring it up just in case. I'm a little jealous. That thing is a beast. I wouldn't be able to power it.

Or a Portal to your heart......

There is no dark side of the moon really; as a matter of fact, it's all dark......

It looks like he's in the ballpark there. It's the unknown steel that concerns me. It would have been good to cut off a small piece of the tang (assuming you had a little extra material there) and do a test quench and temper on that to get an idea of how the steel will respond to heat treating. 10 hours from the start to the point of heat treating on a sword is far from excessive. If anything it might be a little on the low side. Regardless, with an unknown steel and therefore uncertainty regarding the heat treat ..... let's just say I wouldn't want to be standing nearby the first time that sword hits something solid. It may be fine, but you should approach any testing with it as if you expect it to fail to avoid injury to yourself or anyone else. If you do get a phone, tablet, camera, etc. (or could borrow one) so you could show us what you've made I'd love to see it.

I posted some details about the NARB powered by a 1/2" T burner I built a few years ago here: https://www.iforgeiron.com/topic/48001-naturally-aspirated-ribbon-burner-photo-heavy/page/6/ You may have to scroll down a bit to get to it. I used that in a forge whose shell was a disposable freon tank. I had no trouble forge welding with it.

The only times you want to heat the entire length of the blade on a sword are the heat treating processes. Even for those you can "pump" the blade in and out of the forge to obtain an even heat. Tempering would be a bit tricky that way, but generally speaking forges running naturally aspirated burners can't reliably be turned down and hold specific temperatures in the tempering range anyway. If you're forging using a hand hammer you'll only be able to work about 6 inches at a time before the stock needs to go back into the forge for reheating. Especially for a long, relatively thin blade you really don't want a lot of excessive heats that can degrade and/or decarburize the steel. The chuffing you're getting after 30 minutes or so is most likely due to the chilling/freezing of the propane tank. You are running 3 burners off a 30 lb tank. It is pretty much inevitable that you will see reduced pressure due to the temperature drop with that setup. You can get a bigger tank, link 2 or more tanks together, or place the bottom of your propane tank in a water bath to reduce that problem. Or you can construct a smaller forge that doesn't require that many burners and therefore that level of fuel consumption. A lot of us had to learn that lesson the hard way.

To take this a step further: we often hear about planning for "the worst case scenario," and in certain cases that makes sense. However, when it comes to allocating both time and resources we're frequently much better off planning for the range of most likely scenarios. As a silly example, you may be concerned about your house being burglarized. The worst case scenario you might be able to think of could be a group of highly trained, technologically skilled thieves and murderers who possess the knowledge and skill to defeat alarm systems, cut through inches of steel, and escape without a trace. However, the most likely scenario is more along the lines of a couple teenagers looking for easy targets of opportunity. A dog and a deadbolt will handle the most likely scenario, not so much with the worst possible scenario.

Just one more observation to throw in there: Your T's are all lined up with each other. If they are close enough they may compete for air to induce. If you turn them 90 degrees that shouldn't be an issue. It may or may not be an issue now, but if it is going to cause problems it will be when running at higher psi than you are using in those videos. It is fairly common for multiple burner forges to create some additional challenges. It's common for one burner to function well but other burners to show substandard performance in use. Small variations in construction and back pressure within the forge chamber can cause some frustrating scenarios. I'm fairly sure (as the others have mentioned) that your problem with the flame burning inside the mixing tube is due to low pressure. I think BBQ regulators are typically set around 1.5 to 2 psi. That's not enough to make most T burners function properly. I'm assuming this is just test firing and you still plan to add insulation and refractory material to create the flame face and keep the burner ends from protruding into the forge chamber. I don't know what you plan on using your forge for, but that thing looks like a well-built gas-guzzling beast to me. Long decorative bends and twists are about the only things I can think of that would require that much forge for a hobbyist. Most of us had to realign our thinking from "better to have it and not need it" overkill to "what's the smallest I can build this thing and still do what I want to do?" The up front construction cost pales in comparison to the long term fuel consumption costs of an overly large forge. Beyond that, propane forges that are unnecessarily large result in consistently reheating more steel than can be worked by hand before the stock needs to go back in. This can cause excess degradation of the steel - especially high carbon steel.

Hmmm. Was that chicken nugget forged or fabricated?