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 Well with my last post I was despondent and lost.  My hard brick had been stolen form my seller? I did pour the concrete the next day and my cinderblocks are in place, rearranged a 1/2 dozen  times!

 I have 700 IFB's purchased at 71 cents each, man has about 10,000 more. I think they could be had at much less then I paid! My hard bricks arrived Thursday.  My copy of Niles Lou's "Art of Firing" arrived yesterday.  My burners arrived today and their guts sometime next week.

 When I first signed on here I said that I needed a kiln . That I have pieces but no way to bisque or glaze fire without taking them to a friend in town and not getting them back until she could fire them for me, I said I didn't have 208v to the garage and did not want to incur the expense of having an electrician run the wire  and then I still would have to purchase  a  kiln and learn to operate it. After all I have built a raku kin with a weed burner all I needed to was to go bigger. SO I was going to build a gas kiln and thought I could do so for around $1200.

Someone, anyone could have told me I was dreaming a fool's dream. Someone I will not mention any names but someone told me "that when you  come to a fork in the road take it". Well I did and I find myself at the foot of Mt. Everest with a load of gear  and I am hopping that you people will become my Sherpa.  I have no real earthly idea what I am doing.

When last we spoke I was building Mel Jacobson's copy of a Minnesota Flat Top and I was a committed forced air man. Well not so much any more.  I am still building the flat top but  I was going to do so with a single forced air burner of my own build. After pricing everything out I thought that having Mark Ward build it for me would be a wise decision.  After talking to Mr. Ward he said that a one burner set-up like I was planning was a reinvention of the wheel. Jacobson does call for 2 burners so. Mr. Ward said I could achieve my results with 2 MR 100's low pressure, I am using propane . I do not remember if Mr. Ward told me what the BTU's out put would be but at this time I do not know. I am guessing 500k btu's each?

 Now the questions??? 

  The kiln will have 9" K23  walls with a fiber interior.  I have a degree in overkill from the "The School of Hard Knocks" and have traveled down the wrong fork many times. It's interior space will be 36x27x 27.5 or 30'' tall.  With the first shelf set 2" off the floor. Jacobson has the intake ports set at 4.5x4.5 for 40.5sq in and the exit flue at 4.5x7 for 31.5sq in.   All Ward would say about that was "what goes in must come out"! Ward said I could get  away with a chimney that was 8ft. off the floor.   Is this a tall enough stack?  The flat top in the book has the flue box dimensions at 9x9x17 constricting down to 4.5x7 and then emptying into the stack,  I have 8ft. of 9"riser tubes.

 There will be more questions to come but for now.

  Oh and can I add an umbrella roof vent cap to the stack to keep the rain out without restricting the exit gases?

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5 hours ago, postalpotter said:

Still here!

 Well with my last post I was despondent and lost.  My hard brick had been stolen form my seller? I did pour the concrete the next day and my cinderblocks are in place, rearranged a 1/2 dozen  times!

 I have 700 IFB's purchased at 71 cents each, man has about 10,000 more. I think they could be had at much less then I paid! My hard bricks arrived Thursday.  My copy of Niles Lou's "Art of Firing" arrived yesterday.  My burners arrived today and their guts sometime next week.

 When I first signed on here I said that I needed a kiln . That I have pieces but no way to bisque or glaze fire without taking them to a friend in town and not getting them back until she could fire them for me, I said I didn't have 208v to the garage and did not want to incur the expense of having an electrician run the wire  and then I still would have to purchase  a  kiln and learn to operate it. After all I have built a raku kin with a weed burner all I needed to was to go bigger. SO I was going to build a gas kiln and thought I could do so for around $1200.

Someone, anyone could have told me I was dreaming a fool's dream. Someone I will not mention any names but someone told me "that when you  come to a fork in the road take it". Well I did and I find myself at the foot of Mt. Everest with a load of gear  and I am hopping that you people will become my Sherpa.  I have no real earthly idea what I am doing.

When last we spoke I was building Mel Jacobson's copy of a Minnesota Flat Top and I was a committed forced air man. Well not so much any more.  I am still building the flat top but  I was going to do so with a single forced air burner of my own build. After pricing everything out I thought that having Mark Ward build it for me would be a wise decision.  After talking to Mr. Ward he said that a one burner set-up like I was planning was a reinvention of the wheel. Jacobson does call for 2 burners so. Mr. Ward said I could achieve my results with 2 MR 100's low pressure, I am using propane . I do not remember if Mr. Ward told me what the BTU's out put would be but at this time I do not know. I am guessing 500k btu's each?

 Now the questions??? 

  The kiln will have 9" K23  walls with a fiber interior.  I have a degree in overkill from the "The School of Hard Knocks" and have traveled down the wrong fork many times. It's interior space will be 36x27x 27.5 or 30'' tall.  With the first shelf set 2" off the floor. Jacobson has the intake ports set at 4.5x4.5 for 40.5sq in and the exit flue at 4.5x7 for 31.5sq in.   All Ward would say about that was "what goes in must come out"! Ward said I could get  away with a chimney that was 8ft. off the floor.   Is this a tall enough stack?  The flat top in the book has the flue box dimensions at 9x9x17 constricting down to 4.5x7 and then emptying into the stack,  I have 8ft. of 9"riser tubes.

 There will be more questions to come but for now.

  Oh and can I add an umbrella roof vent cap to the stack to keep the rain out without restricting the exit gases?

As a new kiln builder why are you thinking of fiber at all with two layers of soft brick. Thats plenty of insulation without fiber.

The 1200$ is low ball as you now know.

.71cents a brick is a great deal be happy

Mr 100s are 100,ooo vs the MR75s which are 75,000- those two MR100s should do the job with propane (i'm not a propane guy ) but it has more BTUs than Natural gas.

I'm the fork in the road guy-my back says no to sherpa duty

The bottom shelve needs to be above the flue opening so that 2 inch off the floor may not work well. That is since its a downdraft. That way the gasses go under the floor not thru the load.

I think that small kiln will draw at ok with and 8 foot stack. The top hood need to well above the top otherwise it will interfere with draw. I have tried a few top vent caps and had to remove them all because it slowed exit gases. I suggest it be many feet above the top of stack. The flue liners need to be kept dry.

Hey down there( bottomMt. Everest with a load of gear)welcome to the climb

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Funny Mark C. funny!

Looking forward to the climb, just sorry I choose the steepest route. 

 So first shelf say 5in. off the floor? I really really  really just don't understand the placement of only 3 posts per shelf? I have only loaded an electric  kiln twice and not under a teachers instruction. Me, King of Over Kill would use 5 for the floor shelf and one where ever I could put one on the shelves above but I have read otherwise. It just doesn't seem right to the rookie who  actually wants a shepra  to carry him most  of the way up!

 

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2 hours ago, postalpotter said:

Funny Mark C. funny!

Looking forward to the climb, just sorry I choose the steepest route. 

 So first shelf say 5in. off the floor? I really really  really just don't understand the placement of only 3 posts per shelf? I have only loaded an electric  kiln twice and not under a teachers instruction. Me, King of Over Kill would use 5 for the floor shelf and one where ever I could put one on the shelves above but I have read otherwise. It just doesn't seem right to the rookie who  actually wants a shepra  to carry him most  of the way up!

 

The idea of the 1st shelve just coving the flue is to make the heat go UNDER shelve .So whatever flue hole size you make put that Botton shelve at top of that hole.If the hole is 4 inches make the shelve at 4.5 inches-5 inch high flue hole shelve at 5.5 inches inches. Just cover the hole.I like hard bricks at the floor post points and hard bricks as the 1st shelve supports before any shelving.

Now as to posts-the 3 point stand is the most stable without rocking.using 4 or 5 or 10 posts you will notice only some touch the shelve the others do not as most shelves are not perfectly flat.

In high fire all these fine points multiply to larger errors. You can screw up the stacking in a cone 08 fire and survive(no issues) at cone 6 the heat and load can really matter if you have stacked pots wrong near Bottom of load. At cone 10 their is no forgiveness .

Rookie mistake list is long-in fact its a whole thread thats yet to be covered.

her are a few

Stacking kilns many do not line posts up-mistake

Using to many posts-mistake

The first shelve off kiln floor can have cut bricks under the stack points so the posts on 1st shelve can move around some with out line up issues. that gives you a larger surface area for strength as well. Posts can settle into soft brick floors with larger loads over time at high temps .Seen it happen a many times.

My 35 cubic foot natural draft car kilns(firing right now) has 4 MR100 and 4 MR.75s its a bit overkill as I used to only have 8 MR75s but wanted a little kick if needed.

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5 minutes ago, Mark C. said:

The idea of the 1st shelve just coving the flue is to make the heat go UNDER shelve .So whatever flue hole size you make put that Botton shelve at top of that hole.If the hole is 4 inches make the shelve at 4.5 inches-5 inch high flue hole shelve at 5.5 inches inches. Just cover the hole.I like hard bricks at the floor post points and hard bricks as the 1st shelve supports before any shelving.

Now as to posts-the 3 point stand is the most stable without rocking.using 4 or 5 or 10 posts you will notice only some touch the shelve the others do not as most shelves are not perfectly flat.

In high fire all these fine points multiply to larger errors. You can screw up the stacking in a cone 08 fire and survive(no issues) at cone 6 the heat and load can really matter if you have stacked pots wrong near Bottom of load. At cone 10 their is no forgiveness .

Another point on shelves not covered is some are stronger at high temp than others.

Advancers are much stronger at cone 10 than room temps-this is not the case with many materials

Rookie mistake list is long-in fact its a whole thread thats yet to be covered.

here are a few

Stacking kilns, many do not line posts up-mistake

Using to many posts-mistake

Not lining pots up with funder floor posts-mistake

The first shelve off kiln floor can have cut bricks under the stack points so the posts on 1st shelve can move around some with out line up issues. that gives you a larger surface area for strength as well. Posts can settle into soft brick floors with larger loads over time at high temps .Seen it happen a many times.

My 35 cubic foot natural draft car kilns(firing right now) has 4 MR100 and 4 MR.75s its a bit overkill as I used to only have 8 MR75s but wanted a little kick if needed.

 

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I disagree about the bottom shelf.  It does not have to be above the flue opening- it will work just fine with the flue being level with the floor. I've built many kilns that way and they work great.

Like Mark said, ditch the fiber. It's not necessary and not worth the extra work and health risks.

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Even if using a rigidizer? Lou says"use it with ITC 100 I have some rigidizer  from Laguna. Lou say's the tighter the better, insulation saves  radiation loss and fuel both will weigh down my ascent. Won't hurt will it???

 Okay I said my interior was 36x27x30 but is really only 341/2 x27 so I will only have a floor shelf 20x20 or 22x22? Flame path??? do I need space for gasses to return through the floor shelf?  So do I need a floor consisting of four 10x10, two 10 x 20 or can I use a 20x20?

 

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1 hour ago, postalpotter said:

Even if using a rigidizer? Lou says"use it with ITC 100 I have some rigidizer  from Laguna. Lou say's the tighter the better, insulation saves  radiation loss and fuel both will weigh down my ascent. Won't hurt will it???

 Okay I said my interior was 36x27x30 but is really only 341/2 x27 so I will only have a floor shelf 20x20 or 22x22? Flame path??? do I need space for gasses to return through the floor shelf?  So do I need a floor consisting of four 10x10, two 10 x 20 or can I use a 20x20?

 

Ok I will agree with Neil on the floor height but I still would split the flue difference so all the heat does not travel thru the lowest shelve. My car kiln lower shelve splits the flue.

My salt kiln does not split the flue-its below

As to fiber you need to know a lot to get it right. I do not think on a soft brick kiln you need fiber as its overkill.

Yes use rigidizer if you use fiber . Spray it on -also you need to have some lift or loft with fiber as it shrinks and will get smaller.This is a whole other topic.If you are going to use fiber I can say more

As I have said all along-build you kiln around your shelves not the other way around. 12x 24 are the standard size

none of your sizes are standard  sizes.

Keep in mind shelves can weigh a lot so the large sizes weigh a ton and are hard to handle.I also have found the larger the shelve the more likely warpage is at high temps over time-the only exception is advancers that never warp.

Standard size shelves are 12x24 or (11x22 to some degree ) so are 14x28-theere are some others-I suggest you look say Bailey ceramics web site and check out the kiln shelve pages-there are 3 pages of  shelves made from 3-4 materials-

yes you can get other sizes but only in certain materials like mullite. but you will be limited from the start.

Decide your kiln shelve size and build the kiln around that.

I have 3 gas kilns now, I made  two around the standard 12x24 shelve size the 3rd kiln is a commercial one made around 12 x18 shelves which are a pain as they are two small-I stack 4 on the bottom and finish the stack with 12x24s(its an updraft 12 cubic footer)

Edited by Mark C.

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I know you have told me many times to build the kiln around the shelves. Having nothing to start with and  having never seen this mountain except in pictures I have just finished the floor I have my flue framed, the ports built and the door worked out and blocked. I have part of a wall started and I have quit for the evening. 34.5x27 is my interior. 

 " I can't get to sleep
I think about the implications
Of diving in too deep
And possibly the complications
Especially at night
I worry over situation

Day after day it reappears
Night after night
My heartbeat shows the fears"

Colin Hay

 

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Sounds like two 12x 24s will work well-two shelves together is 24 inchs leaving 3 inch in front and 24 wide leaves 12.5 on side or side or whatever plan you have for bag wall or walls

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7 hours ago, Mark C. said:

Sounds like two 12x 24s will work well-two shelves together is 24 inchs leaving 3 inch in front and 24 wide leaves 12.5 on side or side or whatever plan you have for bag wall or walls

Bag walls??? The flat top calls for no bag walls both Lou and Jacobson  say they are not needed?  And I haven't planned for them ???

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Bag walls are a holdover from the time when kilns were fired with coal thrown (or blown) into the fire pit.  The bag wall was the equivalent of a backsplash used on a kitchen sink - to keep the water from damaging the wall.  The bag wall kept the fine clinkers from being carried from the fire pit onto the first row of ware.  The debris problem is solved with fuels such as natural gas and propane, therefore a bag wall is not needed.  In fact most bag walls are a hindrance to good circulation of combustion gases throughout the kiln.  

LT

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11 minutes ago, Magnolia Mud Research said:

 

Bag walls are a holdover from the time when kilns were fired with coal thrown (or blown) into the fire pit.  The bag wall was the equivalent of a backsplash used on a kitchen sink - to keep the water from damaging the wall.  The bag wall kept the fine clinkers from being carried from the fire pit onto the first row of ware.  The debris problem is solved with fuels such as natural gas and propane, therefore a bag wall is not needed.  In fact most bag walls are a hindrance to good circulation of combustion gases throughout the kiln.  

LT

Actually, bag walls are often very important, especially in downdraft kilns. It's not about debris, nor do they hinder the circulation of gases. In fact, they help the circulation by forcing the heat upward before the flue can draw it down and out, thereby making it much easier to keep the kiln even from top to bottom.. A bag wall does not need to be really tall, just tall enough to do the job. Often, as little as 6 inches will do the job.  They also help keep the flame from the burners from hitting directly onto the ware loaded along the fireboxes.

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Many kilns do not use bag walls. Bag walls are not used much when the burners point up in floor. In downdrafts with burners pointing in on sides that flame will overheat the wares that it is blasting . You  need to get that heat and flame going up to top to even out the temps. In Lou's kiln layout he uses two forced air burners and a target brick.With natural draft burners (not forced air) the flame is long and gentle  and not has hot as a forced air burner. You need to make sure this flame goes up towards kiln roof not strait into exit flue-thats where a bag wall comes in.It stops flame /heat from exiting the flue to fast creating hot spots down low. The height will be determined by trail and error .

On my car kiln I have 4 burners per side pointing towards the load hitting a tall bag wall and forcing the heat going up. Since the kiln is pretty tall(6 feet inside) so is the bag wall.

Since you only listed two dimensions 34.4 Wx27 D????? I have no idea how tall your kiln will . If you are going with two rear burners like Lou's flattop you will need something to get the natural draft going up.Remember he used forced air high BTU burners. Natural draft NR100 are not those.

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Shelf stacking:  a useful technique to allow the use of shelves that, side-by-side, would be too wide is to overlap them by an amount that will allow you to place smaller items beneath the overlap. Posts go on outside corners and at center of overlap (always aligned with lower posts). This sort of stacking not only allows heat to travel through the center of the load, but can give you a little more clearance for fingers on the sides when loading. In my catenary kiln, this kind of staggering was essential, but it works in square and rectangular kilns as well. 

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Thanks Mark and Neil,

 I have the bricks for a bag wall but after reading Lou  I thought I could forget it. I am already using 1 1/4 HB for the outside wall 9in tall. I have some for the inside as well. Can I shrink the line of travel to 3 1/4 in. wide, after all the flame will only be traveling 27" to the back wall? 

Edited by postalpotter
height

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14 minutes ago, postalpotter said:

I have the bricks for a bag wall but after reading Lou  I thought I could forget it. I am already using 1 1/4 HB for the outside wall 9in tall. I have some for the inside as well. Can I shrink the line of travel to 3 1/4 in. wide, after all the flame will only be traveling 27" to the back wall? 

I'm not sure what you're asking here.

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I am trying to save overall shelf space . Interior space is 27" long and 34.5" wide. if I make a bag wall with a channel only 3 1/4 wide down each side ( the 27 in. walls) then I have about 27 in. for shelving and space for the return gases. I have set the outside HB into the 9''wall just so I could get that 1 1/4 on both sides just so I can get that overall 2.5 in. back to the return gases and gain some shelf space. Remember I am working under the illusion I know what I am doing.

Ward's burner system arrived today. 

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I think you draw a rough sketch and post it of the floor plan looking down and amber a front view looking at flue. That would be worth a 1,000 words right now for me.

The bag wall can be made from hard brick splits that are 1.4 inches thick 4.5 wide and 9 inch long if that helps you space wise-I dit just that in the Molokai salt kiln gas conversion I posted a few moths ago.You can buy them on Amazon just be aware one or two could be broken as they send them in an unpadded box-of course I was mid pacific so handling was much more and harder than here on the mainland.

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Sorry folks,

Cant move the photos from my phone to the computer and the phone doesn't email.

Did some reading and it seems you people call  it a flame trench. Mine will be 3 3/4 W x 9 H x27 L. The port 4 1/2 x 4 1/2 and then tapered down. I was wondering if that width was sufficient but it doesn't matter at the moment because that is what mine is.

I long for the days when a pound of coffee was 16oz. I found out my HB's are a 1/16th short in LxW and only 2 1/4 H while my splits are exact as are my IFB's. Makes keeping things close to square and level an interesting bit of creative rearranging. 

Is there a form Q & A on terms and meanings for the novice?

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I'm now wondering of you have fireplace hard brick not high fire hard brick. The two ways to tell are high fire hard brick have stamped names on the flat side-do yours? Where did your hard bricks come from?That will answer this for me usually.

and the color is usually a bit different than true stamped hardbrick . The fireplace bricks are usually no name and are slightly irregular brick to brick (Not made to hardback standards)If you have fireplace bricks -forget about using them in the lower part of kiln near any burners or flame trench as you call it.

The port 4 1/2 x4 1/2 is fine no need to taper.Just keep it the same size.Whats keeping the flame in the trench from going out the exit flue straight away?I call those bricks bag walls.

I'm assuming your two burners are on the back wall?

To help us a floor detail would really help.Maybe a friend with a phone can e-mail you a photo and from there you can post it?as its on your computer.

Edited by Mark C.

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OMG I think I have just had my first fall going up this damn mountain.  I have only held one HB in my hands and the ones I have seem to me to be more fragile then that one. The bricks I have I was told come from Pinehall  and have no markings on them. 

 Is cursing allowed in this forum? How bad is this screw-up?  Will they last if I only fire to ^6

bagwalls.jpg

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With Venturi burners going horizontally, there needs to be a baffle (not necessarily a whole wall) a few inches in from the port to deflect the flame/heat upwards and to the sides.  Your trench is for forced air.

it sounds like you're thinking that you can't stack shelves above the trenches, but you can.

 

Are you doing a stacked brick chimney up the back side? Fireplace brick will probably be ok for that. Sorry you're on the steep side of the learning curve, although that's where the best lessons are. 

 

Wait...how do you access your burners when they're plumb up against the chimney?

Edited by Rae Reich

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