Jump to content


Photo
- - - - -

Building A Small Cantenary, Mortar Question


  • Please log in to reply
14 replies to this topic

#1 Wyndham

Wyndham

    Advanced Member

  • Members
  • PipPipPip
  • 434 posts
  • LocationSeagrove NC

Posted 25 August 2014 - 08:19 AM

John's pic of the kiln build has inspired me to dust off plans for a small soft brick cantenary car kiln. The 2 kilns I previously built were dry stacked but I noticed John used a mortar.

I was wondering if it is fireclay used for leveling each course or kiln cement to hold the brick in place. my concern is material from the mortar, falling into the pots during firing. My last 2 kilns were sprung arch with  ifb in the arch that contained no sand, those were used in the side walls.

Any thoughts?

Wyndham



#2 JBaymore

JBaymore

    Moderator

  • Moderators
  • 3,025 posts
  • LocationWilton, NH USA

Posted 25 August 2014 - 09:12 AM

Depends on what you are trying to do.

 

Most of that anagama build was hardbrick.... even dry pressed are not uniform in size. And mixing IFB and HB is really uneven....... hence mortar.

 

Three different ones were used....... leveling, spacing, and bonding. Leveling and spacing are the same ... fireclay and silica sand. Ratio of sand to fireclay varies. Bonding is used where you need a bond to develop....like arch skews.

 

Light dips on the sprung arch or not at all if it is IFB.

 

If you want to take it down and reuse bricks.... no bonding.

 

best,

 

..............john


John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#3 Wyndham

Wyndham

    Advanced Member

  • Members
  • PipPipPip
  • 434 posts
  • LocationSeagrove NC

Posted 25 August 2014 - 12:31 PM

Thanks John. The biggest issue I've seen with cantenary is that the walls may "suck in" from the burner channels where the flames work against the side walls in the fire box area. Still, it will last me many years before needing rebuilding .

Wyndham



#4 Mark C.

Mark C.

    Advanced Member

  • Members
  • PipPipPip
  • 3,071 posts
  • LocationNear Arcata Ca-redwood rain forest

Posted 25 August 2014 - 11:57 PM

If you plan on reusing the bricks  ever do not mortar. 

In my past catanaries we never mortared except for the reasons John mentioned. 

In my present kiln a sprung archcar kiln I have no mortar-I did mortar the chimney as I wanted it air tight and its permanent.

Another option is a non binding homemade mortar which will add space but will not stick well to the bricks. This will clean up easy years later

Mark


Mark Cortright
www.liscomhillpottery.com

#5 Biglou13

Biglou13

    Advanced beginner pottery, Advanced in other art

  • Members
  • PipPipPip
  • 1,042 posts
  • LocationNorth Florida

Posted 26 August 2014 - 05:55 AM

What's your non binding recipe?
If a cant' arch Is built with all straights there will be a lot of spaces needing filled? Can u use non binding?
Any capping recipes? And does capping allow reuse of bricks?
Caution big brother is watching.
The beige is blinding!!!!!!
The middle of the road is boring

The true sign of intelligence is not knowledge but imagination.
-Albert Einstein

#6 JBaymore

JBaymore

    Moderator

  • Moderators
  • 3,025 posts
  • LocationWilton, NH USA

Posted 26 August 2014 - 12:31 PM

Lou,

 

My general leveling mortar is 75% fireclay (the best you can get) and 25% 80 m silica sand.  No fired bond at all... just filling in the slight gaps and a light "wet bond" during construction work (like clay on a wheelhead)......until it dries out.  Comes right off with a straight trowl years later (if no ash on it).

 

Personally if I was building a cat with straights....... I'd use commercial castable to angle the backs of the bricks.  Castable is cheap... about $35 a bag.  The slight savings in initial $ you might get in making a home-made castable is not worth the lack of longevity.  If it is a temporary 'rubble kiln'........ just use straight fireclay and silica sand at 50/50.

 

Building any arch with straights.... that you want to last... is a serious art.  Not the province of a new kiln builder.

 

Capping (stucco) does not typically cause issues unless the insulation properties of the UNDER layers are insufficient to keep the hot face of the stucco below its fusion point.

 

best,

 

................john 


John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#7 JBaymore

JBaymore

    Moderator

  • Moderators
  • 3,025 posts
  • LocationWilton, NH USA

Posted 26 August 2014 - 12:43 PM

Thanks John. The biggest issue I've seen with cantenary is that the walls may "suck in" from the burner channels where the flames work against the side walls in the fire box area. Still, it will last me many years before needing rebuilding .

Wyndham

 

If you are getting that you are using too low a duty refractory on the hot face of the firebox.  In building I always use higher rated refractories in the firebox areas... they are subject to higher temps and more extreme atmosphers than the general chamber bricks.

 

For a typical cone 10 gas kiln....... I'm using 2800 IFB in there.  In the anagama we just built.... super duty in the whole main firebox area (arches, walls, floor, etc.) and also in the areas of the sidestokes.

 

But I alsio typically try to build gas kilns to last 30+ years in production use. (An example... kiln still going strong......  http://www.martymorg....com/about.html)

 

best,

 

...............john


John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#8 neilestrick

neilestrick

    Neil Estrick

  • Members
  • PipPipPip
  • 2,807 posts
  • LocationGrayslake, IL

Posted 26 August 2014 - 01:07 PM

On a cat you can probably get away with straights and mortar up to a point, but near the top where the arch curve gets tighter it would not be a bad idea to throw in some arch bricks if you've got them. That said, the cat crossdraft wood kiln I fired in grad school (graduated 1997) lasted for years and years built with all straights. It may still even be there.


Neil Estrick
Kiln Repair Tech
L&L Distributor
Owner, Neil Estrick Gallery, LLC
www.neilestrickgallery.com

neil@neilestrickgallery.com

#9 JBaymore

JBaymore

    Moderator

  • Moderators
  • 3,025 posts
  • LocationWilton, NH USA

Posted 26 August 2014 - 01:10 PM

On a cat you can probably get away with straights and mortar up to a point, but near the top where the arch curve gets tighter it would not be a bad idea to throw in some arch bricks if you've got them. That said, the cat crossdraft wood kiln I fired in grad school (graduated 1997) lasted for years and years built with all straights. It may still even be there.

 

Yup... typical cat, once the skews are set at the correct angle....... it's usually all straights for about 5-7 courses, and then a slight angle one and a few more straights in a row. Only near the top does the spacing get large.

 

best,

 

..............john


John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#10 Marcia Selsor

Marcia Selsor

    Professor Emerita, Montana State University-Billings

  • Members
  • PipPipPip
  • 4,078 posts
  • Locationwhere Texas, Matamoros, Rio Grande and Gulf of Mexico come together.

Posted 26 August 2014 - 01:47 PM

i used a mix if fire clay , sawdust and vermiculite at the time 1971 for filling between the bricks on the curve. ( excuse the little hippie chick image)
I built this kiln in update NY with old bricks from a boiler in the woods. Empire firebricks.and an outer layer of insulation bricks. there had been an urban myth of using aluminum foil between the bricks but it really did nothing. Turned pretty much to ash in a firing or two. I did cover the exterior with a thin coat of home made castable which I have posted here before.This was a cross draft catenary. I built a larger cross draft in Illinois for oil burners. Those burners were in an article in Studio Potter in 1973.I cast some ridged plastic lampshades in a block of castable for the burner ports. I built another kiln for burners on each side of the door in Montana.-no photo.

Attached Files



#11 JBaymore

JBaymore

    Moderator

  • Moderators
  • 3,025 posts
  • LocationWilton, NH USA

Posted 26 August 2014 - 02:44 PM

Nice looking oil kiln, Marcia.

 

Few folks do that anymore. (if you do want to do that .... search the term "clinker" and be prepared. ;))

 

best,

 

..............john


John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#12 Marcia Selsor

Marcia Selsor

    Professor Emerita, Montana State University-Billings

  • Members
  • PipPipPip
  • 4,078 posts
  • Locationwhere Texas, Matamoros, Rio Grande and Gulf of Mexico come together.

Posted 26 August 2014 - 03:12 PM

Read all about them (clinkers) in the Potters book by Leach. We solved it by eliminating cold secondary air by making a collar of firberfax around the tube of the oil burner and sealing the burner port.

Marcia

#13 Wyndham

Wyndham

    Advanced Member

  • Members
  • PipPipPip
  • 434 posts
  • LocationSeagrove NC

Posted 26 August 2014 - 03:42 PM

First catenary i built was a cross draft dry stack 12 cu ft from a small book on space age kiln  building materials. I used IFB and cut the skews on a table saw. When I got to the top of the arch I used castable for the key way. On my first firing I used some old style advancer shelves that had been stored in the open for several years.

About 1/2 hr or less in the firing the kiln BLEW up.The shelves had moisture trapped in them and it looked like a stick of dynamite had gone off, but the cat stayed in place but too much damage to repair, that was 1996

My second kiln was a sprung arch with cordierite shelves, 30 cu ft, didn't blow that one up. :) IFB and finished wearing out the table saw cutting the IFB for the arch.

I think I have over come my fear of Catenary's, I'm going to try it again sans advancer shelves :)

Wyndham



#14 JBaymore

JBaymore

    Moderator

  • Moderators
  • 3,025 posts
  • LocationWilton, NH USA

Posted 26 August 2014 - 04:38 PM

Yeah... when wet Advancers go.... it is pretty impressive.

 

best,

 

.............john


John Baymore
Immediate Past President; Potters Council
Professor of Ceramics; New Hampshire Insitute of Art

http://www.JohnBaymore.com

#15 Marcia Selsor

Marcia Selsor

    Professor Emerita, Montana State University-Billings

  • Members
  • PipPipPip
  • 4,078 posts
  • Locationwhere Texas, Matamoros, Rio Grande and Gulf of Mexico come together.

Posted 26 August 2014 - 04:49 PM

Wyndam,
My first solo catenary is the one in the first two pictures above. My bricks had gotten wet. I fired the kiln with burners I made following Don Bendel's design. He was at NAU Flagstaff. I fired it really slowly and it looked like a cloud machine the way the steam came off that thing. It eventually dried out and gave good firings.
The oil kiln was a good one too. Nice reds, temmoku, stoneware matts that I prefer. We had modified those household furnace burners that have one nozzle at a rated BTU output. We put 3 nozzles in each one with .75, 1, and 3 gallons/hr output which was more than we needed. But we did "beat the clinker" (sounds like beat the reaper) by eliminately the cold secondary air. Clinkers are really an amazing phenomenon, hard carbonized soot.And they can clog up a burner port really well.

Marcia




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users