To Greg,

While I was reading page 125 of Burners 101 your thread disappeared. I am more than wiling to answer your questions, if you will post them again.

In the meantime, two 1/2" burners are sufficient to heat a five gallon forge, such as the one in my book. However, your burner flame needs a little tweaking to come up to snuff. You also mentioned uncertainty about where to place them in such a forge. Separate the forge body length into thirds, and place one burner on the line between front and middle third. Place the other burner on the line between middle and rear third.

Next comes what way to point them. The very best position is two inches above the forge floor and facing upward and inward; this allows the longest distance for combustion to complete before super-heated oxygen molecules can impinge on the material you are heating.

However, with burners this small you could even place the burners at top dead center and get by with it 

You need to get back to us about tweaking your burner to get the hottest flame; it probably will not take much.

Mikey

it looks like Greg gave up, and moved on. So, for those of you who copied the photo of his burner; while his air openings were less than perfect, they were probably adequate to induce one hundred percent combustion in a single flame envelope. The photo also showed that the flame was centered over the flame retention nozzle's exit. So, what was missing? Nothing in the burner's construction. However the amount of overhang of the flame retention nozzle past the end of the mixing tube must be not less than the inside diameter of the mixing tube, and no more than the equal of its inside diameter plus 1/16". All he probably needed to do was shorten the length of the nozzle's overhang less than 1/8" to tune the burner properly.

The forum lost a majority of it's members during Covid, some literally and most trying to keep out of the poor house. Not many have resumed posting here. It's a real bummer so many smart and interesting folk left us. 

I've heard about smithing fora starting up but haven't seen any take off and even the old regulars sites seem to have faded to archive sites. <sigh>

Theforge.list hosted by ABANA is still up but hardly anybody sends an email. I check in once in a while but it's very slow.

Frosty The Lucky.

 

I’m here but not so technically advanced regarding posting.  I kept looking at my inbox for any reply to my email and didn’t see anything.  Old dogs are hard to train.

What thread should I post on?

You're good right here Greg. Mike will be along when he checks . . . whenever that is. 

Speaking of old dogs and new things. My stupid computer mouse updated so it doesn't work at all now and I'm afraid I removed it trying to figure out what happened. Well, that'll teach me, I guess I'm not supposed to know. 

Frosty The Lucky.

Thanks Frosty.

Mike/Frosty - We settled on the design below.  I forge knives in the 4-12” range so we need to decide on length.  2 or 3 half inch burners?

I may opt to increase the internal height by shaping more like a mailbox.  3.2 inches as is may be inconvenient.  Thinking 5-6?

Thoughts?

That burner is running really rich! I'll leave getting that tuned to Mike, he's better at it. We have two very different methods and his is easier to explain.

The floor of your forge is silly over built and putting fire brick anywhere in a propane forge is detrimental. Just the kiln shelf and two layers of 1" blanket refractory is more than enough floor, you're not forging crank shafts even a long blade only weighs ounces and it'll be distributed over it's length.

Last we talked about it the consensus was 1/4" of a quality castable hard refractory, Kastolite 30 being a favorite was more than enough for the flame face liner backed by two layers of 1" ceramic blanket refractory. ALL blanket being rigidized and cured!!

A chamber 5" x 5" x whatever length you need is more than enough for making blades up to a decent sized hawk. 

Frosty The Lucky.  

Frosty,

Sorry to butt in here, but... what are you seeing that leads you to a diagnosis of a rich flame?  At first glance I thought it looked pretty good.  I do see multiple flame envelopes, but not the colors I'd normally associate with a rich flame.  What did I miss?

Buzzkill

You missed very little. In fact it is so close to a perfect flame as to be best left alone at this point, for anymore tinkering will require looking at the forge's atmosphere and exhaust first. 

No, there aren't multiple flame envelopes, but one envelope. What you are seeing is the flame's internal and external surfaces, because these burner are designed to burn from the exterior, as normal; but also from its interior surface. Also, there is some evidence at the forward end of that single envelope has metallic oxides burning; with such a new flame retention nozzle, that is likely to be left over particles from cutting, etc. Especially because the nozzle is not yet fully heated.

However, I suspect that his flame is running a touch lean. The only cure for this is playing around with his burner, until he learns all its ends and out. In other words, time is the best cure for that.

As to the forge floor, Frosty is quite right. The only brick that should be used as forge floors are Morgan K26 insulated bricks, and even these should have a coating of Kast-O-lite 30. As to the Perlite, it is a good idea so long as there is insulating brick or ceramic wool separating it from the heat of the forge interior. I am totally in favor of Perlite as tertiary insulation. I am also in favor of increasing the exterior of a forge's body (steel shell). enough to include that tertiary Perlite insulation.

The number one mistake of newbies is making oversize forges. However the second most common mistake is not allowing  enough room for primary, secondary, and tertiary insulation layers. Heat reflective coatings are also a good idea, but are what I call add-ons; that is anything external or internal that can be done to a forge, after its construction. 

Got it on the insulation.

How many 1/2 burners assuming the chamber size above (but increasing the height from 3.2” to 5”) with a length of 16”?

I must've been thinking of another burner when I said it's running rich. It's close enough to good I'd need to test it and see if it oxidized clean steel in the flame or not.

The only time I've recommended 1/2" of Kastolite was for the floor if the forge was going to see heavy use and 3/8" for the remainder of the liner. Before Kastolite 30 a forge needed thicker hard refractory and earlier still needed stainless needles mixed in for reinforcement or thermal cycling just broke them up.

While Plistex is an excellent stand alone refractory it's darned expensive and makes a better "kiln wash" a final protective layer between the flame and refractory liner. Especially against forge welding fluxes containing borax in any form. Molten borax is as caustic as lye and literally dissolves standard silica based refractories and fire brick like a sugar cube in hot water.

One of the problems reading the archives or things posted on old fora and such is much of the info and opinions are dated. Improvements in refractories, high temperature insulation and fire brick is always changing.

The only real reason for a fire brick in a propane forge is as a sacrificial floor that is easier and cheaper to replace than relining a forge when the hard liner floor wears out. Everything in a propane forge suffers from the extreme rapid temperature changes, Thermal Erosion. Anything going from ambient temperature to 2,400f or higher temperature in a few minutes is enduring severe thermal shock. 

One last thing. Greg, the dimensions of your forge do NOT determine the number of burners necessary it is the VOLUME. I do not do basic math for people anymore. Being a rectangular box it's as easy as simple multiplication, length, x width x height = the volume in cubic inches. For anyone building in metric simply convert the initial measurements to mm and do the math that's all there is to it.

The required number of burners is simple and printed in plain English in the T burner directions I published a few decades ago and found on IFI in the propane burner section. 1 ea. well tuned 3/4" naturally aspirated propane burner will bring 300 - 350 cu/in. of volume to welding temperature.

Two 1/2" propane burners is equal to One 3/4" burner.

Frosty The Lucky.

 

2 hours ago, Frosty said:

One of the problems reading the archives or things posted on old fora and such is much of the info and opinions are dated. Improvements in refractories, high temperature insulation and fire brick is always changing.

How true that is, Frosty! I recommended high alumina kiln shelves as forge floors for decades, and I still would today, if they hadn't become too darned expensive. I laughed at insulating fire bricks just as long...until Morgan K26 insulating firebricks hit the market. Everything changes, including pricing on new versus not so new things.

  The one thing that never changes is ignorance tax, placed on people who will not do a little research before they buy stuff 

You and I spent too long on different fora email lists, etc. I never considered kiln shelf and when I checked it out after hearing your reasoning I was appalled at how expensive it is, even broken and partial pieces from ceramics studio waste bins. Once they found out someone wanted it it was off my list.

I tried for quite a while to MAKE insulating firebrick work but could never get a second firing before they started to crumble. Morgan K-26 is the BOMB, though If I crank the burners hard enough for long enough even they will degrade. 

Ever read R. A. Heinlein? A recurring adage in a few different books and stories, "Stranger In A Strange Land" spouted by Jubal Harshaw at one point is, "Ignorance can be cured. Stupidity is it's own death sentence." Sort of implies ignorance can be taxing but not the end eh?

I know I've been paying the ignorance tax my whole life though the rates keep going down. Unfortunately new stuff keeps coming out and I'm ignorant again. <sigh>

I don't think there's a bottom to this one but I can hope. <sigh>

Frosty The Lucky.

Yes; I read all his books that I found in print. I even agreed with about half of what he thought (the other half was appalling).

9 hours ago, Frosty said:

Unfortunately new stuff keeps coming out and I'm ignorant again. <sigh>

Sooner or later it is time to pass the torch. If the next generation does not reach out and take it, tough stuff, I don't have to care 

A lot of what Heinlein wrote was under contract for a magazine and he didn't get a choice on the subject, how they were edited, some rewritten even. They owned his name for years or decades but it kept a roof over his, Virginia and and the kids heads. The post WWII boom let him start writing what he wanted for a better publishing house. 

His last novel was 1967 but much of the 60s culture was loosely based on, "Stranger In A Strange Land", published in 1961. My favorites being "Glory road" and "The Moon Is A Harsh Mistress."

As much as I buried my nose in his books while I was growing up in S. Cal. I had no idea he and Virginia lived maybe 25 miles away. 

I'm still a fan even if I roll my eyes a lot at the science he bases things on. Bear in mind though much was written when the first atomic energy was going to power everything. Did you know a few companies were working on air liners powered by atomic reactors?

Funnier still, micro reactors are getting close to small enough to do it but jet engines are smaller lighter and more powerful than any prop drive CAN be. 

Yeah, I'm still a fan and reread my favorites every year or two. Have them on Kindle audible now so I can listen while doing stuff. 

Life in the future ROCKS!

Frosty The Lucky.

1. My first sci-fi story was one of the Skylark series; I got it from the Rialto CA city library, around fifth or sixth grade. Eventually I bought all of E E Doc Smith's books. Heinlein came a decade later.

Yeah, I remember the "age of the atom" craze in the fifties. Kathy and I liked the ant monster movies that came out of it best. We used to watch reruns of them on TV in the seventies. Then Mexican versions of them came out, like one with giant devouring scorpions derailing trains; they were hilarious 

I just looked up Doc Smith and darned if he and my maternal Grandmother weren't born 11 days apart in May 1890. Not that matters I just thought it was neat.

He was a food engineer and liked telling stories centering on fantastic technology and epic challenges. I don't know when I ran across the first one but remember the title, "Skyark Duquense."

Of course there was a list of publications in order. 

"Skylark Of Space" was a written between 1915 and 1920 with Mrs. Garby as co-author and published in Amazing Stories Aug- Oct, 1928. "Skylark Duquense," published in "Worlds Of If", June to Oct 1965.

It lists everything and I only posted the one for GP. I didn't remember and details count in discussions.

I didn't read them all, the Skylark and Lensman series and a scattering of others. They weren't really my style, too much "Hale Fellow, Well Met." and "Right Back At Ya!" Fantasies for me, I've always been interested in how things work so consistent science and tech rates high. Even when I was just learning to read.

Clifford Simak and A.E. Van Vogt held me for quite a while. Van Vogt was writing from the early 20thC till his death in 2,000. I might have to check out some of his later work, it was always strange and thought provoking. 

Ah yes, the Atom age movies, you liked Them too eh? You a Ray Harryhausen fan too? 

"Them" is my favorite giant mutant bug movie and once the craze started selling tickets some real dreck got pumped out. You know, such classic masterpieces as "Attack Of The Fifty Foot Woman."

I gotta sign off, I'm really rambly right now thinking about Deb.

Jer

On 9/7/2025 at 5:42 PM, Frosty said:

Ah yes, the Atom age movies, you liked Them too eh? You a Ray Harryhausen fan too? 

"Them" is my favorite giant mutant bug movie and once the craze started selling tickets some real dreck got pumped out. You know, such classic masterpieces as "Attack Of The Fifty Foot Woman."

I was a total fan of his movies. My favorite special effect was the fighting skeletons in Jason and the Argonauts. Even while watching, I was admiring how they could pull it off so believably 

Attack of the fifty foot bimbo was total dreck; what a waste of film.

Deb on a trip? I used to have to work hard at not missing Kathy during her yearly trips to Europe. Fortunately, she and her best friend Marilee got too old to put up with half a month there, and just do at week at a time, these days.

Ahhh, the skeletons! A truly great animator. It wasn't until they got CGI polished special effects started surpassing his work.

Deb was having a pacemaker installed, tuned and tested, we only got home about 2 hours ago. Even exhausted and really sore she looked better than before, good color, more energy and . . . heck, just good. She's upstairs napping and I'm back on pack mule duty for a week or so while she heals up enough not to pull a wire. 

Frosty The Lucky.

I kind of have a soft spot for a lot of the really bad ones, the worse the better. It's hard to beat Plan 9 from Outer Space but Lord knows there's plenty of candidates - the giant creeping eye comes to mind, any number of bad Italian 50s and 60s vampire movies with redheads and gratuitous nudity, attack of the killer tomatoes (before you ask, each and every one of them), anything with a kaiju in it including 50 ft. women across the remake spectrum, modern versions like Tammy and the T-rex or Dead Alive, Cocaine Bear, the Pirhana movies, or Sharknado. Even a lot of the great Vincent Price movies were pretty schlocky - take a look at the bat, or The Last Man on Earth - which was a Richard Matheson story and gave birth to the zombie movies - "They're coming to get you, Barbara!" For that matter, White Zombie.

Hope Deb gets better over the procedure soon.

Scary movies gave me nightmares when I was young so I wasn't allowed to watch any, like I wanted to. I was in my teens before I watch an episode of Chiller or Thriller or the Twilight Zone. Remember the one about the hen pecked banker who's wife wouldn't allow him to read, then something killed everybody while he was in the vault and he was celebrating being able to read everything ever written on the steps of the library, dropped his glasses and stepped on them. The closing scene was him sitting on the steps of the Metropolitan Library with books stacked everywhere and it fades. 

Then there was. "They're COOKBOOKS!" Was that the "Twilight Zone" or "Outer Limits?"

Old and cheesy with bad even for the day special effects are fun. On the other hand I really like  some of the new ones like, "Battleship." Or "Cowboys and Aliens." Twisty, weird and fun is good.

Kaiju are good, I LIKE kaiju. How many GodZirra moves do you think have been made, well more than a hundred, Couple hundred? I like Rodan movies too.

Frosty The Lucky.

I watched the first Godzilla movie; it was boring, but I forced myself to finish it. Never watched another. I did see some twisted horror comedy mystery movies, and then an of alien cowboy and a couple horror time travel types back in the eighties, and must agree; twisty is cool. I used to spend Halloween night at the drive-in, watching old horror comedy flicks like Abbot and Costello meets Frankenstein; the mummy; the wolf man... 

Never had nightmares about any of it. Instead I had a recurring nightmare where I fell through stars all night long (or anyway it seemed like it); then it changed and I was being chased down a slope by a giant boulder. Kathy took me to see the Indiana Jones movie on the big screen just to surprise me with its boulder sequence. And women think guys blockheads!

 

9 hours ago, Frosty said:

How many GodZirra moves do you think have been made

Depends on how you argue what's canon, but generally speaking, 39, 34 from Toho, 5 American and the last two or three have been really, really good - I thought they'd mess it up. Kaijus are legion, almost like zombie movies. I agree - the original is boring, love it anyways, like reading all the bits about whale trivia to get to "from the heart of hell I stab at thee!" in Melville.

Twilight Zone memes are still very relevant in our house - whenever my kid goes full ADHD and wastes a half hour or I get asked to do something just as I'm sitting down - "It's not fair...It's not fair, I had all the time in the world." Or when somebody starts doing Duolingo full blast without their headphones on, "IT'S A COOKBOOK!!!"

Godzilla #1 is pretty basic and not much. Heck, Godzilla isn't the monster's name, the director of the first American release didn't like the Japanese term and had it dubbed to what he thought Americans would accept or whatever. Maybe he thought Kaiju sounded too cute and cuddly?

For the most part the genre is cool special effects of cities being stomped to dust, lots of Japanese movies follow the theme. I think it could be a cultural trait that's been caused by lived under a monster threat for  centuries.

Oh yeah, Abbot and Costello meet X monster movies were fun. I liked them but they were about as far into the Alpha character beating on the sidekick, as I could stand. Couldn't go over to a friend's house without watching 3 Stooges movies so I must've built up a tolerance. I never actually liked them even though I picked up a couple things. There was one Curly used to say frequently most of us used to to express what we thought of a stupid idea, action, like saying "Good Idea" sarchastically.

I was one of those Boomer kids with 2 parents working and a Grandmother keeping the house. Mother used to sit me in front of the TV and run errands, or whatever. I definitely remember my life improving quite a bit when Mother FINALLY showed me how the horizontal hold worked! The vertical hold was on the face of the TV but horizontal was on back. I was allowed to change channels if nobody else was watching, later I was the remote control. Anyway, remember the old sci fi serials? Buck Rogers, Rocketman, etc. From the 1st. time I saw it I had trouble believing the people making the films could be so stupid as to have characters entering aircraft by belly flopping on the roof and opening a door in the side. Some even opened outwards. Sure it's a meme from paratroopers in WWII. 

I was thinking total Godzilla movies made, I'm not fan enough for canon to even occur to me. The first one was less than 10 years post Hiroshima and Nagasaki and featured burned and flattened cities.  

About that Mike, in woman-think, all men are blockheads while to us most women seem to have the mechanical aptitude of a random number generator. Balances out pretty well though.

Frosty The Lucky.