Forges 101

[jwmelvin]

A thought on Kast-o-lite for those new to it. I did not appreciate before using it how crumbly and unable to support itself it is. I highly recommend carefully making forms for it before you start mixing the KOL. That way you will have ways to support it and define the surfaces you want. Posterboard seems to be sufficiently strong to make a form; I just wish I would have had a full form ready to shape and hold the KOL. It turned out okay after a couple iterations of patching but I have only fired it once and don't know long term how it will fare. 

[Mikey98118]

I've  never had a problem with Kast-O-lite 30, but always cast it between forms.

[Buzzkill]

11 hours ago, jwmelvin said:

I did not appreciate before using it how crumbly and unable to support itself it is.

By the way you worded your post I'm assuming you are talking about the properties when casting rather than after it's cured.   I've applied it to rigidized fiber blanket without any real problems of crumbling or keeping it in place.  However, if you apply it to a dry and porous surface, that will suck moisture out of the mixture and that can cause problems.  Even your posterboard can pull water from the mix if it's not coated with something impervious to water.  That's why Frosty preaches "buttering" the contact surfaces before applying the refractory mix.  There is also a benefit to vibrating the object it's being applied to.  After that you want maximum humidity while it cures.  Some people have sealed the entire project in a plastic bag.  I've draped a thoroughly wet towel directly over the Kastolite and added water to the towel a few times over a couple days when it was hot outside.

It is a small amount of water that takes you from too dry to too wet though, so when close water should be added in very small amounts and mixed thoroughly for a couple minutes to ensure consistency throughout the mix before adding any more.

Molds are a good idea for the product, but again you want to make sure your mold material isn't pulling moisture from your refractory.  The first time I used sonotube I did not deal with the issue and had a crumbly cast as a result.

Just my 2 cents based on my experience.

[Frosty]

My NARB forge has an upwards domed floor because I turned it over to apply the Kastolite to the roof too soon. For what we do we need to make it wetter than the company recommends. Remember Kastolite does NOT DRY, it is WATER SETTING. It's two part, water is absorbed and forms a different compound with the calcites in the binders. If you're using a mold it NEEDS to stay WET to cure properly. I'm liking waxed or greased linoleum better and better. It's smooth, strong, water proof, bends easily and smoothly, there are good adhesives commonly available. Even better a flooring company will let you dumpster dive for trimmings if you have decent PR skills. What's not to like?

Well said Buzz, you have the right of it.

Frosty The Lucky.

[jwmelvin]

Good advice all. My KOL seemed to set and fire fine, but it was, as Buzzkill guesed, working with it before it set that I found difficult. With premade forms, it would not be nearly as difficult. I think it turned out pretty well though for a first forge. 

[AngryDaddyBird]

Just an update on my forge build. I made a mount for my burner and played with the air gap from the burner flush with the forge so no air could come in around it and pulled it away up to 2 inches to let in max air mixture. I also played with making different nozzles. I found that a 1/2 to 3/4” gam on MY SETUP works best. I have forgewelded several times already so its hotter than I need it to be. 1 standard BBQ tank Lamar me 12+ hours of forge time making Flint strikers. I have the materials to insulate my forge and will update here when I start the process. If you haven’t seen my forge search MICRINI forge to seethe build. This place has been a wealth of knowledge for me!

[Frosty]

Posting the same thing in more than one thread is not only a waste of bandwidth for people who have to pay by usage, it's poor etiquette. What's bad in your case is it makes folk stop looking at your posts, after a while folk just think they're duplicates.

Frosty The Lucky.

[Old Crew]

I am a Newbie as such I have questions.

I am building my first forge.

To preface I have some character flaws which stem from my background. I can be very anal about things at times. I also am a firm believer in more / bigger is better !

I have been a welder for decades , I have a steel fab and erect business . I am German , born in Germany raised in Oregon and have lived in Texas for the last 20+ years.

To sum it up I have proper German anal sensibilities mixed with a large dose of "everything is bigger in Texas"

Before I found this site I had started planning to build my first forge out of hard fire brick with a counter weighted and hinged lid so that the entire top lifted up easily the interior dimensions were going to be 12" wide by 9" tall by 36" deep. It would have a modest 2.25 cubic foot volume ( 3888 cubic inches ) with a removable baffle at  2/3 of the depth and 2 Pine Ridge ribbon burners 1 small and 1 large. I figured that would take care of all my needs with 1 Forge.

I   (my wallet)  am VERY thankful that I found this site.   Soooooo after reading all of the ribbon burner pages all of the forge 101 pages and many other pages from the burner section and others. I have decided that maybe the forge I was planning was to big.       ACCEPTING this  caused me PAIN , mentally , emotionally (as much as can be for Germans) and Physically, My stomach still hurts from typing it for the whole world to see!

After several round s of denial and finally acceptance I was back to the drawing board. 

My round 2 thoughts after some of this helpful reading , was starting with a 16" by 36" tank lined with kaolin-wool and castable and D shaped with an elevated floor still with 2 burners.  It would have  a vertical sliding baffle made from 1" kiln shelve at the 2/3 point.  This sliding baffle  could pinned a certain heights if needed.  This would have given me 1 chamber of 690 cubic inches , 1 chamber of 1380 inches and with the baffle raised 2070 cubic inches or 1.2 cubic feet. Still big but not Texas Big.

After continued reading on this forum I found myself asking why so big? So after much painful down sizing I decided to draw another trough sketch and try to get some feed back. This is my round 3 basic shell sketch .

I have a 12" by 24" tank as the starting point with the kaowool ,kastolite , K26 brick and kiln shelve I am left with about 30 cubic inches per linear foot of forge

 

 

[Old Crew]

My questions are :

1      Mike mentioned in 1 of his posts to use as thin of a kiln shelf as possible for the floor.  Why?

2      In the forges 101there is a post stating the volume capacity of 3/8 and each size larger burner . Is this based upon standard burners Mikes burners or Frosty T burners . Are the volume           numbers still applicable to Frosty or others NARB burners.

3      With forge shape above what would you more experienced Curmudgeons recommend for burner placement and burner type (still contemplating pine ridge burners, not sure if I want to build my own NARB or just build Frosty T burners)

4    What am I forgetting/ doing wrong with this design ?

I am planning to have front and back doors and a chimney . 

Thanks for all of the info and research done by you experienced guys (you know who you are)!

David

[Mikey98118]

(1) High alumina kiln shelves are seven time more insulating then hard clay firebricks; but they are still a solid refractory, and therefor something of a heat sink; how much depends on how thick.

(2)  I make general recommendations based an the average burner; well tuned enough to produce a neutral flame and to finish combustion before leaving the forge interior.

Too answer any more questions I would have to read that postage stamp drawing; it wou not enlage.

[Frosty]

4 hours ago, Old Crew said:

"everything is bigger in Texas"

You could cut Texas in half and be second and third largest states. We love Texans touring Alaska, they're fun to needle. My in laws are mostly Texans and S. Californians. 

Uh let's see, the rule of thumb is one each well tuned 3/4" burner to bring 300-350 cu/in to welding temp. IF the chamber is more or less mono-dimensional, roughly spherical or cubic, long narrow chambers benefit from multiple smaller burners.

Ribbons seem to be more effective heating the chamber I believe it's largely because the flame velocity is low so the flame stays in the forge longer and transfers more energy to the liner. 

I copied your sketch to another window and hit ctrl + until I could read it. I general it's a proven design but lose the brick floor. If you make if flat by filling the bottom curve with Kaowool feathering the edges so they blend smoothly with the sides and rigidize it more than the rest it'll make a fine floor. The final blending is with the hard refractory and kiln wash if you wash it. I like about 1/2" of hard refractory for the floor, it takes more beating than the walls.

Frosty The Lucky.

[Irondragon Forge ClayWorks]

True story, we always went to breakfast at the restaurant in the bowling alley where there was a long table that most of the farmers would sit & tell their stories (the liars table). One day there was a transplanted Texan sitting there bragging about just buying a 160 acre farm. He asked Bill "what's your best crop here". Bill replied Texans, he had sold the same farm a half dozen times when the buyer's went broke and he repossessed it.

[JHCC]

One of my favorite jokes involves the Texan quizzing the Vermont hill farmer on the extent of his property (the teller of the joke can insert here a lengthy monologue detailing boundary markers and their respective histories) and then bragging, "Down in Texas, I got me a spread where I can get in my pickup and drive all day without coming to one of my boundaries!" The Vermonter replies, "Ayup. I had a truck like that once."

[SLAG]

Mr. Dragon,  Mr. JHCC,  et al.,

'Ayyup',  Texas is a big place, indeed.

But some years back  SLAG Industries   (L.L.C.) bought an enormous spread in Antarctica.

We are breeding thoroughbred penguins there.

SLAG.    ( CEO),

p.s.  great joke John.

[Frosty]

Tourist questions in general are pretty entertaining even if you give them a straight answer. I've been asked when the queen Salmon run, the family had seen the King Salmon. Let's see (an interjection to separate tourist questions) Ummm, "what season do Caribou turn into Moose. One of my favorites was the gentleman standing on the ferry dock who demanded a purser's mate, addressed him as Captain, he had braid you know. He demanded to know what the elevation was. The poor purser's mate was looking pretty stricken he just didn't know what to say so I rescued him. I didn't know his rank so didn't try I just said, "I think I can answer that for you, you have a LOT to do getting the ship loaded." I sort of combined a wink and rolling my eyes and asked the gentleman to step to the bull rail on the dock. I picked up a piece of debris, wood chip I think, held it in my left hand so I could start the stop watch. (Cassio calculator watch is my sort of trademark) While he was jabbering about how rude people are not answering simple questions. Just a second sir, dropped the debris and stopped my watch when it hit the water. Then I turned to the mate and asked him where the tide was and said . . . Something. 

Then I spent some time fiddling with my calculator watch, it takes me a lot of time and a pad of paper to work acceleration, distance, etc. calcs. We were about 28' above sea level at that moment but I was reading the depth marks on the Ferry's side. 

A BUNCH of people had gathered around to discover what the answer was going to be, the guy had been pestering a lot of people. We were in Haines the tides don't run as high there as in Cook Inlet but they're still significant, 22' IIRC. And I told the gentleman to paraphrase, "Without dropping a tape measure I calculate the dock is approximately 30'(?) above the current sea level, of course this changes with the tides."

I don't recall exactly what I said but his expression is burned into my memory. 

Tourist questions, gotta love em.

Frosty The Lucky.

[Irondragon Forge ClayWorks]

Gotta love tourist town too. There is a motel in town that has on their marquee "Please don't pet the Moose" the only thing is, the statue below it is an Elk.

[pnut]

2 hours ago, SLAG said:

We are breeding thoroughbred penguins there.

I prefer draft penguins. They have a friendlier disposition.

Pnut (Mike)

[John B]

I prefer these  chocolate ones,       

[ThomasPowers]

I prefer my penguins daft; they tend to put up better with me.  What was that old chant "Draft Beer, Not Students!"

(Actually seeing the line of penguins across the monitor tells me that the linux boot has progressed...)

[Mikey98118]

Ceramic fiber, or insulating firebrick?

For many years ceramic fiber insulation in walls and under the floor has consisted of two one-inch thick layers inside curved forge walls, and single layers of ceramic board, with a further 1” layer of ceramic blanket between the board and shell, in box forges.

    Two one-inch layers of ceramic fiber insulation outside of a hot-face layer is the minimum that is normally considered adequate for heating equipment; one-inch of insulation normally isn’t. How much insulation is adequate depends on other factors, such as how small the equipment is, and how long the heating cycles are. In other words, circumstances can alter cases.

Morgan’s Thermal Ceramic K26 insulating firebricks have become a  tougher alternative to ceramic board in box forges and a better alternative to ceramic blanket under floors in tunnel, “D,” and oval forges; they are use rated to 2600 °F (1427 °C), and available from eBay and other online sources; shipping charges are small because these bricks are very light weight. Other K26 rated bricks are not anywhere near as insulating, nor as lightweight; with the addition of several layer of high temperature coating like Plistex 900, or a 1/2” layer of Kast-O-lite 30, these bricks can even be used as a hot-face layer in forges and casting furnaces.

    K26 IFB bricks can be cut by hand with a hacksaw, but are more  quickly cut with ceramic cutoff blades: they can be cut with ordinary drill bits, but drill faster with carbide tipped bits; unlike ceramic fiber products, they are resistant to hot flux.

    These bricks have become popular over the last two years, their prices on eBay have effectively doubled, but now they can be purchased from more and more sources like High Temp Inc., at reasonable price and shipping charges.

     There are several kinds of refractories used for hard firebricks, but only one kind was historically used for insulating bricks, until recently: that was the pinkish to yellowish bricks made by including a foaming agent in clay to make lightweight bricks use rated to 2300 °F (1260 °C), that you see employed all too often in old gas forges, and electric pottery kilns. To call them friable is to completely understate their unsound nature; calling them future rubble is more to the point, when they are used in equipment with rapid heating cycles.

    While the strength and durability of various insulating refractory vary widely, all of them have a good insulation value in an environment that is at or above 2000 °F, but that of Morgan’s K26 brick equals that of ceramic fiber blanket products at these temperatures. On the other hand, their K26 bricks can provide some structural integrity, while the blanket can easily be shaped into curved forms and then rigidized into featherweight insulation for secondary insulation.

    Even the cheapest grade of ceramic fiber blanket doesn't melt below 3000 °F. Product temperature ratings come from the level of heat the fiber will withstand without massive shrinkage; this should illustrate the importance of locking the individual fibers in more secure positions by rigidizing; it also demystifies the seemingly magic protection given by a relatively thin sealing coat of high-temperature refractory, capped by a heat reflective coating. When you exceed its use rating it begins to wither.  If you exceed 1900 °F (1038 °C), Perlite and the sodium silicate it is usually bonded together will, both quickly melt.

    Ceramic fiber products need both rigidizer and finish coatings to do well in today's gas heated equipment; this is because better burner and forge designs create much higher internal temperatures than were likely twenty years ago. Rigidizer is especially important if you want your insulation to last. On the other hand, between using 2600 °F (1427 °C) rated fiber insulation and rigidizer, you can toughen the secondary insulation layer in your equipment enough so that it should stand up well to the heat that will leak past a high emissive coating (AKA heat reflector) and thin hot-face layer like Plistix 900F® (rated to 3400°F; 1871 °C) or Matrikote 90 (rated to 2500 °F; 1371 °C). Rigidizer also helps mechanically support a thin coating, or cradle a cast refractory layer.

(A) You don't want to use thick ceramic fiber layers; instead of a single 2" thick layer, use two 1" thick layers. Ceramic fiber blanket will easily part into thinner layers via delamination, if you mistakenly purchase 2” thick blanket.

(B) Rigidize each layer after installation, and heat cure it with your burner, before installing the next layer.

(C) Form the burner openings before rigidizing each layer. Remember to leave burner openings just a little oversize so that they can be finish coated with a hot-face layer.

(D) Dispense the rigidizer from a used cleaner bottle with a spritzer top unto fairly horizontal surfaces, and heat-set the ceramic fibers in position, before rotating curved surfaces to position further areas for the same treatment.

(E) Silica rigidizer is colloidal silica (just fumed silica, which remains suspended in water) and common everyday food coloring (to allow you to visually judge how far it is penetrating into the fiber); this water born product is easiest to dispense by spritzing. You can always pay through the nose for premixed rigidizer from a pottery supply if you prefer; I buy mine through eBay and Amazon.com and get free delivery.

[Swadly]

Mike final coating of the forge quick question about Zircopax. Do I need to add a binder to the mix? It says its bound by Sinter on DigitalFire.com but its not listed in the Zircopax formula.

 

Thanks Swadly 

[Frosty]

You'll need a binder using Zircopax as a kiln wash a propane forge doesn't make the right conditions to sinter zirconai. A couple % of bentonite seems to work well. Read some of Monkey Forge's posts re zirconia refractories. He's done some pretty scientific experiments with good success though he was experimenting with making forge liner type refractory. Still. . .

Frosty The Lucky.

[Mikey98118]

Frosty has the right of things. Thus far, making Zircopax into a solid refractory is no slam-dunk. It is much easier to use it as a coating--not more worthwhile though

[Swadly]

Thanks Gent's

[Swadly]

Thanks Gent's

 

How do you get the rigidizer powder to mix in water?