Forges 101

[Mikey98118]

In the five gallon propane forge, I think I used 2" from TDC, along with aiming the burner vary carefully, but 3" should work out okay. However, you only want to aim the flame about one-third of the way in from the kiln shelf edge. You want avoid aiming the burner at your work pieces. Even though there will be no VISIBLE flame impingement from a properly tuned burner, there can still be super heated gas molecules, which can chemically interact with the metal; why take the chance of going there?

Okay; you could do much worse than to use that old book. Everything in the text is straight forward. There is zero padding, obfuscation, and B.S in it. BUT, the information is also dated; my designs were the last word, then. But a lot more words have been added my a lot of clever people, since. You need to read Burners 101, and Forges 101 threads if you want know all those changes; should you want all the edge you can get. If you just want rock-on equipment, it will deliver.

Getting the most out of Gas Burners for Forges, Furnaces, & Kilns

The first thing you won't find mentioned in the book, is that a few years after it came out there was a quiet revolution in rotary hand tools (electric die grinders to our generation), and their accessories, which changed from over priced and underfed, to powerful and cheap. So, for get using a small angle grinder.

The next thing is Larry Zoeller's change over to 1/8" schedule 80 pipe nipples for the gas tubes; this makes a more powerful gas accelerator, which can be threaded directly into, for the MIG tip. These advantages are well worth having to special order the part, rather than picking the schedule 40 version at your locale hardware store.

After thousands of burners were built around the world, my six un-puckered, and I started making the burners with only three air openings, no matter what their sizes; this configuration is more powerful than five or six openings, which I used as an added safety feature, back then.

Finally, I would recommend using two 1/2" burners (instead of the single 3/4") with a movable internal baffle wall in any five gallon propane cylinder forge, it will allow you to heat with half the fuel for most of your work.You need well contained heat in your forge; not blasting into your shop.

I shouldn't need to say that the smaller non-returnable Freon or helium cylinders make a better size first forge, but it's no big deal. It can always be a second forge. I think most smiths who even heed this advice, simply end up building the five gallon size later on. So, most people will just reverse the cycle, and arrive to the same end point

[customcutter]

Sorry, I don't have a copy of the book.  The only downloads I've seen require joining a book club, which I am not apt to do.  When I first found this site, I read about half of Burners 101, then NARB, back to finish Burners 101, then Forges 101.  At almost 63 my memory isn't what it used to be, also trying to learn about something that I have absolutely no knowledge of puts beginners at a great disadvantage when you and Frosty are describing things.  

When you say to aim the flame approx 1/3 of the way in from the kiln shelf edge, I would assume that you mean on the same side of the forge as the burners are located on based on my background and how hydrosizers and cyclone seperators work.   However, every picture I see shows a burner mounted top dead center aimed at the work, or they are mounted slightly off center pointed directly across the forge.  Both flames are impacting the floor or wall straight on, no where near what would produce a circular or cyclonic flame IMHO.  Maybe I just haven't seen the right picture yet?   

Here is a link to a diagram of a cyclone seperator.  The type we used were for seperating solids from liquids in phosphate mining.

https://blogofchemicalengineering.wordpress.com/2015/09/26/cyclone-separators-design-calculation-wiki-mini-for-chem/

thanks, Ken

[Mikey98118]

16 minutes ago, customcutter said:

When you say to aim the flame approx 1/3 of the way in from the kiln shelf edge, I would assume that you mean on the same side of the forge as the burners are located on based on my background and how hydrosizers and cyclone seperators work.   However, every picture I see shows a burner mounted top dead center aimed at the work, or they are mounted slightly off center pointed directly across the forge.  Both flames are impacting the floor or wall straight on, no where near what would produce a circular or cyclonic flame IMHO.  Maybe I just haven't seen the right picture yet?   

There is always a perfectly logical reason not to follow sound advice. During all the years that book was in circulation, there were people who just couldn't make up their minds whether to cough up a twenty, or take a chance on a pirate site. Now the book is out of circulation, and people have to pay hundreds, or down load from a pirate site. When those few copies are gone, things will get even weirder.

I spent two years of my life learning what I needed to know, and then two more years writing that book, so that some people could be very happy with what they found in it. There just isn't time or strength enough, for me to worry about all of the others anymore.

 

 

[customcutter]

I apologize if I have offended you.  I would gladly pony up $20 for a copy.  I have actively searched in several used book stores for a copy of your book, but have not found one.  Used books on Amazon are still approaching $100 as of this morning.   

I don't know your health condition, but it sounds as if you are in poor health, I hope and pray that it improves.  I will try not to bother you with trivial questions.

thanks, Ken

[Mikey98118]

You didn't offend me. I just suffer increasing bouts of irony from so much time watching the parade pass. And yes, the book not being very available  frustrates me too. In the meantime, information must be passed forward.

So, as to your questions: You asked " When you say to aim the flame approx 1/3 of the way in from the kiln shelf edge, I would assume that you mean on the same side of the forge as the burners are located on based on..." Yes, the same side. This slows down the flame, without stopping its swirling path within the forge, and is less likely to allow it to impinge on the work, which is usually placed in the center of the forge floor.

You stated "However, every picture I see shows a burner mounted top dead center aimed at the work, or they are mounted slightly off center pointed directly across the forge." Positioning the burner straight down from TDC will result in the flame splitting into two swirls of left and right hand spirals. A friend of mine uses this position in his forge with success. But his burner is turned down very low, so that his flame is short and slow; otherwise his stock would suffer from it. He can get away with the slow heating this engenders, because he only heat 1/4" square bar to red heat. If he used larger stock and needed to work faster amd/or hotter, the straight down flame would have to be turned up, and would impinge on the stock, causing a lot of trouble.

So, why are so many burners positioned at TDC? That's the way most of the first gas forges came out; since the manufacturers don't like to change anything, they still are. If automobile manufacturers played the game that way, road apples would be a big problem on today's highways. Not that this is the only reason for TDC aiming; in the past, it made sense in some brick forges, and small box forges. With the new choices in ceramic materials, that may change.

Mounting a burner slightly off center, and  pointed directly across the forge, would cause the flame to impinge on the weaker wall structure sooner in its path, rather than later. The whole point of your forge's floor is to provide a tougher area for the stock to rest on; one that is resistant, to impacts, flux, and flame impingement. You want the flame to impinge as long as possible on the floor, to save where and tear on the forge walls.

Essentially, your burner and forge are a pile of decisions that are made wisely--or not. If you don't know the reason why someone is doing something different in a design, find out, before copying it. People are usually worried about their forge not getting hot enough, but that can always be fixed; there are a hundred ways to do it. What they should be wary of, is having to look at a forge full of wrong choices, every time they go to use it; that is what gets most forges replaced

 

[customcutter]

Michael, thanks for the response.  When I first came to the site, like I said I did a lot of reading before asking questions.   I've been on the site long enough to see some of the questions that are asked without any searching, or information that might allow someone to answer.  I can certainly understand the frustration that leads to.  I try to search for the answers before asking, and all I've found and read about the flame direction said to introduce it on a tangent, directed toward the back of the forge.  So that's what I'm trying to do, I know most of the older forges were square, so it's hard to get a flame swirl around inside of a box.  Like you say there are a lot of choices to be made.  I'm trying to make better ones, so that my forge and burners are as efficient as I can make them.

[Frosty]

There is one thing I've been wanting to do but keep finding the hard refractory's aggregate is too coarse. Many years ago I was visiting friends at a metal head gathering in south of Chicago and gave the host one of my early T burners for hosting. It got mounted horizontally , lengthwise across the forge (2 burner Whisper Moma) about 1" off the floor. In his experiments to get better performance he'd corrugated the floor. It was a series of rounded grooves like tight waves. 

The way the flame circulated in the forge wasn't ideal though the entire thing got well above welding temp. What really impressed me was how flame circulated under the stock and how much hotter the deck was. I have experimented with the effect by laying coarsely broken fire brick on the floor to get flame circulating under the work. The better result was when I discovered the box of round soap stone "chalks" I drop my soapstone too often, the round ones just break up. Well, laid on the floor with the stock on top was a BIG improvement over the bare deck or broken fire brick. They were too fragile of course and broke up quickly but as an experiment they proved the concept. For me anyway.

I'm thinking this is a perfect way to use the bentonite or Veegum and zircopax in a thicker mix than a kiln wash. 

Frosty The Lucky.

[ThomasPowers]

For experimental purposes:  a stainless mesh raised off the bottom a 1/2" would be interesting to check out.   (Now to scrounge an inconel example...)

[Buzzkill]

Ceramic supports for kiln shelves might be useful there too.

[Mikey98118]

All worthwhile ideas, guys. This new refractory should rewrite the rules for forges even more radically than for burners. These are exiting times. My second favorite new burner (Vortex) is best positioned facing up; the old refractory choices made that an expensive proposition. "Thin thermal "armor" alone is going to be such a game changer!

Customcutter,

There is a wealth of solid information in the book, but why was a question it limited to the burner section. I thought heating equipment like forges were obvious, or would become so, as they were constructed. It took a lot more years to understand that nothing is obvious to anxious people; and first time builders are always anxious. This is why the two 101 threads are heavy on the why of things.

You wrote " I'm trying to make better ones, so that my forge and burners are as efficient as I can make them."

That makes a good direction, but a poor goal. The sharper you get the faster you will see a better way to do things; but as often as not the vision comes just after you have done something already. Better is the enemy of good enough. Both of those dogs can push your sled; just don't get too fond of either one, lest the other bite you 

[Irondragon Forge ClayWorks]

Here is a thread of building our forge beginning to end.

[Mikey98118]

Thank you for the photos; I like that you included a link for the information on its parent thread, so that readers can easily find it in future

[Frosty]

This was in reply to LiveWire's question about lining his first gas forge and using the zircopax and bentonite or Veegum hot face mixes some of us have been thinking about and experimenting with. 

Following is the cut and paste of my response as requested. 

--------------------------

I see you've arrived at the heart of the zircopax + bentonite or Veegum flame face current cutting edge. For us anyway. We're still winkling this stuff out. Mix it thin like heavy latex paint and it's kiln wash. Mix it thick like modeling clay and it's a hard refractory inner liner + flame face. My issue with thick is shrink checking as it dries, too much moisture and it begins displacing clay so when the moisture drys out the clay will shrink. visualize dry mud in a puddle.

However, you ARE making a mistake common to anyone breaking into a new craft. You are trying to design a "perfect" tool and you don't know what you're going to need or want in just a short time. For now think of the first forge as a wear item, it is regardless but the first one wears fast. Even if it's just wearing on the nerves. Everybody does it, all the "old guys" here have forges collecting dust under a bench or out in the yard collecting leaves, I have several. I may be dragging out my large coal forge though one of our guys has located one of the seams of good smithing coal.

Anyway, keep it simple. Have a cat, know someone who does? Cheap clay kitty litter is bentonite. Put some in a jar, put in about 2-3x that much water close the lid and let it dissolve. That's your kiln wash, if it's too watery let it evaporate, adding more litter takes longer and is more by guess and by gosh but works. When it's thick latex paint consistency butter the RIGIDIZED kaowool and just paint it on. When it's dry, bisque fire it with a bernzomatic torch, let it cool and fire up the forge burner for a FEW minutes, let it cool then fire it to red heat and let it cool again. She's ready to rock.

If you want to use it like plaster use less water, peanut butter consistency is pretty darned wet but okay. It's going to take MORE time to dry, an incandescent light bulb and a fan will help a LOT. Be patient it will be rewarded. Fire same as above but skip the bernzomatic torch. A small forge should spend some time in the kitchen oven, 170f. for a few hours then 230f. for a few hours to drive off the hygroscopic moisture. Bentonites should get the 230f. over night at least. That was the standard time for a moisture content test in the lab, about 3:00 pm. to 8:00 am the next morning. Bentonite takes longer but is very thermal shock resistant so over night should be good. If not, you have more, butter and patch the cracks, spalls, etc.

Don't worry about the whole zircopax IR re-radiating hot face / kiln wash thing till we get something worked out that isn't an exercise in "WOW what  happened?  Patience will be rewarded and you get to beat HOT steel in the mean time. Hmmmm?

Frosty The Lucky.

[Mikey98118]

Frosty,Thanks for posting an alternative method to get something done.

[Mikey98118]

Quick, quick; somebody tell a joke before we run out of page 19

[Frosty]

48 minutes ago, Mikey98118 said:

Quick, quick; somebody tell a joke before we run out of page 19

Okay.

A young blonde lady knocks on a well to do Yuppy's door asking if there is anything she can do, she badly needs $50.00. The man asks his wife who says yes, the porch could use a fresh coat of paint on the exterior, the paint and tools are in the garage. They go back to doing whatever this yuppy couple does and in about 45 minutes the young lady knocks and tells them she's finished.

The husband is surprised she's finished and asks if she painted the whole porch. The young lady says yes of course, she even put on a second coat. After counting her $50.00  she says on the way out the front door. "Oh, and that isn't a Porch it's a Lexus."

Will that cover it Mike?

Frosty The Lucky.

[Mikey98118]

Gahan Wilson  could not have done a better yikes, his very own self, Frosty; thank you (LOL)

BTW, that little essay on welding in gas forges should preserved on this thread, too; I never heard any other arguemant slam the door on that old "you can't do it in a naturally aspirated forge" lie. You're on a roll today. 

[Frosty]

Okay, I'm going to start calling 09/03 "cut and paste day".

Another response to gas forge questions follows.

---------------------------------------

Gareth: Don't over think things you can tweak that forge easily, I'd just put a thicker floor in it to reduce the volume as a start. 

If someone can't weld something it only really means THEY can't weld it. There used to be a long standing and commonly accepted myth that you can't weld in a naturally aspirated gas forge. Back before you could search the patent servers without being buried in worthless junk ads you could find patents for "improved" naturally aspirated forge burners from the turn of the last century. Those mostly used brown gas generated on the spot later Mr. Hobart patented calcium carbide water reactor supplied acetylene burners in forges, then oxy acet torches.

Anyway, blacksmiths and especially city farriers have been welding in gas forges since just after, maybe earlier than the Civil War. 

A few years ago I watched an online acquaintance and a neighbor make repeated forge welds (in his farrier's NA gas forge) as cool as med red heat. They got into a friendly speed weld contest and because I was a spectator I got to break them in the vise with a 5lb. single jack sledge. Try to break them actually only a couple out of probably 20 failed. IIRC they were using a can of "Sure Weld" from the early 70s maybe before. 

Welding is a matter of following the steps and like most types of welding the three canon rules are, Clean CLEAN CLEAN!

I don't think that's a bad forge, not what I'd build but I build the things from the ground up, mistakes and all. My most recent forge has a raft of mistakes but works well enough, the next one will be better. 

Frosty The Lucky.

[Mikey98118]

 

thanks Frosty.

[ede]

Here's some photos from earlier this summer.   For those wondering if the zirconium kiln wash with bentonite works or not as a high emissive coating.   In my case I used bentonite at about 5%-- if i recall correctly--with a  zircnium powder mixture.   I've also used the zircopax with kaolin as well.   

The only thing I encountered with both is the way it dries appears like a dried up lake bed.   

Forge is powdered by a 3/4" Mikey burner.

second photo was a heat image done with my iPad.   Last photo if I recall was on cool down.   

[Frosty]

Looks pretty good, especially the psychedelic pic. I see C-O-L-O-R-S !

How wet did you mix the liner? Shrink checking is something that's concerned me. I keep thinking it shouldn't be any damper than absolutely necessary to ram it in. Spreadable like plaster is I'm afraid asking for shrink checking.

How'd it hold up after the tests?

Frosty The Lucky.

[ThomasPowers]

Picture yourself with a forge on a table

with tangerine trees and marmalade skies

Somebody posts, you answer quite slowly....

[Buzzkill]

...'bout the girl with kaleidoscope thighs....

 

Not my fault.  I told her about the bruises she'd get from that anvil orientation.

[ede]

Well if she had iron like thighs instead of kaleidoscope thighs, the anvil orientation would not have been so much of a problem.  

Frosty, I don't remember if I buttered the kaowool before applying the zirconium mixture.   I know you recommend doing this and plan to add it to my routine.  

As far as durability, I've been using a friends coal forge at his place as of late since I don't have a shop currently, so could not tell you about overall long term durability.  

[Mikey98118]

 

Something that jumps out from these photos, is the unusual temperature gradients within the the Kaowool blanket. Normally, ceramic blanket heats quite evenly. What we get to observe is the effect of heat reflection by re-emission; This works in a synergistic fashion with the insulation to slow heat loss by conduction. Conversely, it shows WHY that is important; to keep the hot face radiating energy back into the forge.