Talbott on sun 10 aug 97
During a discussion a potter mentioned that he was aware of someones kiln
that was having roof problems.. (bricks falling in)... it was a flat top.
Why would anyone build a flat top roof instead of an arched roof? What
forces keep a flat top from collapsing?... An arched roof seems
geometrically far more stronger than a flat... Just curious in the logic
of having a flat top... ..Marshall
1ST ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summer 1997)
http://fmc.utm.edu/~dmcbeth/cag/naples.htm
2nd Annual Clayarters' Gallery details will be forth coming!!!
Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box 4116,
Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call first)
WBS Live Chat Room, Sat Nites 10 PM EDT & Sun Afternoons at
1 PM EDT Private Room: Clayarters E-MAIL: clupus@ime.net
kinoko@junction.net on mon 11 aug 97
Marshall, We have built both flattops and arches and would go for the arch
every time....First,becaue it is a thing of beauty...self-supporting with a
minimum of buttressing and only a thin wash of mortar between bricks. Our
largest kiln, a 300cubic ft. Ana-gama withstood several New Brunswick
winters without moving and was operated during several summer sessions.
(Perhaps it is continuing in operation.) Flattops of any appreciable size
require heavy channel irons and rugged threaded rod as well as excellent
'glue' to retain the bricks,and a brick or two will always slip a bit.While
threaded rods through each course of brick will usually prevent bricks from
falling into the kiln,such solutions run up the cost. Anyone who has watched
Mexican or African dome builders at work can appreciate the CASUAL beauty of
the workmanship...and feel certain that unsupported arches and domes will
fall....They do not.Don& Isao>----------------------------Original
message----------------------------
>During a discussion a potter mentioned that he was aware of someones kiln
>that was having roof problems.. (bricks falling in)... it was a flat top.
>Why would anyone build a flat top roof instead of an arched roof? What
>forces keep a flat top from collapsing?... An arched roof seems
>geometrically far more stronger than a flat... Just curious in the logic
>of having a flat top... ..Marshall
>
> 1ST ANNUAL CLAYARTERS' GALLERY - NAPLES, MAINE (Summer 1997)
> http://fmc.utm.edu/~dmcbeth/cag/naples.htm
> 2nd Annual Clayarters' Gallery details will be forth coming!!!
>
> Celia & Marshall Talbott, Pottery By Celia, Route 114, P O Box 4116,
> Naples, Maine 04055-4116,(207)693-6100 voice and fax,(call first)
> WBS Live Chat Room, Sat Nites 10 PM EDT & Sun Afternoons at
> 1 PM EDT Private Room: Clayarters E-MAIL: clupus@ime.net
>
*****************************************
*****************************************
** Don and Isao Morrill **
** Falkland, B.C. **
** kinoko@junction.net **
*****************************************
*****************************************
David Hendley on mon 11 aug 97
>Why would anyone build a flat top roof instead of an arched roof?
An arched roof seems
>geometrically far more stronger than a flat...
Dittos. Why?
I also think that an arched top encourages even flame and heat circulation
in a downdraft kiln. The circulation is up to the top, with no sharp
angles, and then back down.
Kenneth D Westfall on mon 11 aug 97
Dear Marshall
The answer in my opinion is simplicity. You don't need any arch
brick, wedges, key bricks, skews, skew backs, or formula book to figure
out what of those bricks you do need. You also cut down greatly the
amount of heavy steel support you need. The roof is essentially
straight brick strapped together using tie rods. The brick are clamped
tightly from all four corners sufficient (a little mortar for insurance)
to form a solid mass.
Personally, I think its worth the added brick, steel and time to use
an arched roof. I feel you have less problems with bricks falling out
and brick crumbling. But, lots of flat tops are out there and firing
away!
Kenneth D. Westfall
Pine Hill Pottery
potter-ken@juno.com
Don't get stuck in the mud pies K&T
Tom Wirt on tue 12 aug 97
>
----------------------------Original message----------------------------
During a discussion a potter mentioned that he was aware of someones kiln
that was having roof problems.. (bricks falling in)... it was a flat top.
Why would anyone build a flat top roof instead of an arched roof? What
forces keep a flat top from collapsing?... An arched roof seems
geometrically far more stronger than a flat... Just curious in the logic
of having a flat top... ..Marshall
Marshall....
Having built one of Nils' MFT's a bit over a year ago, I promised him
that whenever anyone shot out the Flattop question, I'd speak up.
Well, here goes....the thing fires exactly like Nils says it does, it
does not drop bricks or anything else IF you buils and maintain it
exactly like he says in his book "The art of firing".
Why build a flattop? Much lower cost since you use all straight bricks.
Much easier to build....no forms, just a sheet of plywood. The kiln is
repairable and even expandable just by jacking up the lid. And it gives
more firing space for a given heeight. The concept that an arch gives
more even firing is hooey.
So, get the book, read it and know "why would anyone build a flattop.
P.S. Joe the Potter, it was your comment that finally convinced me not to
do the arch, which was getting about 50%support at the time.
Tom Wirt
Clay Coyote Pottery
Claypot@hutchtel.net
Hutchinson, MN
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