Hank Murrow on wed 16 apr 03
On Wednesday, April 16, 2003, at 07:13 AM, Steven D. Lee wrote:
> I was wondering if anyone knows the approximate layout of Arch No. 1,
> Arch No 2. and straight bricks needed to create a catenary arch
> between 3 and 4 foot high. If I could have this then I coudl
> estimate the brick needed and more importantly the cost for K-26
> brick.
Well Steven;
If you are determined to build a catenary, here is a proven way.=20
Purchase a nice small supply (perhaps 30) of straight brick, less #1=20
arch brick (perhaps 20) , even less #2 arch (maybe only 6 of these)=20
brick. Take these to your studio.
Hang a chain (upside down) between the two points of greatest spread=20=
of the proposed hot face, against a piece of paper until you arrive at=20=
the right height/spread relationship...you have to be the judge of=20
this. The chain should hang free of obstruction. Then spay paint the=20
'shadow' of the chain on the paper. Take the paper down and lay it out=20=
on the floor.
Now, start with the straights on each side (3, maybe 4 straights) until=20=
you need a #1 , then place your #1. Do this on each side, then maybe 2=20=
straights, then #1, then straight, then #1, straight, #1 and #1, then=20
#2 etc. Try to arrange your selection of brick so that the curve is=20
followed as closely as possible. You will have to improvise somewhat.=20
When you have a nice looking arch, take the paper away and rebuild the=20=
arch on the floor again with a clean sheet of paper, or the other side=20=
of the first one. Now draw the exact curve of the shape of your bricks=20=
and build your forms from that curve.
Have Fun, Hank in Eugene (well, still in LA, but heading home this=20
afternoon)
BTW, catenary arches fail eventually, because the sloping wall=20
'pinches' the flame at the top of the bagwall, creating a hotter=20
condition there, the wall expands, pinching the flame more, and the=20
wall expands, etc..........until it chokes off the space between=20
bagwall and kiln wall. Just my observation, of course. takes awhile,=20
but for this reason, I do not consider catenarys to be permanent kilns.=20=
We're talking C/10 and above here, OK Clayart? Don't want to start=20
another faux cause c=E9lebre here.
John Rodgers on thu 17 apr 03
Hank, my understanding of the true cantenary arch is that the "Inside
Base" is ALWAYS as wide as the "Inside Height" ......always! No more,
no less.
That would mean the base of the right triangle formed by the triangle's
base and height would always be a ratio of 1:2. Thus a cantenary arch
with a hot-face height of 4 ft would have a hot face base of 2 feet. in
it's right triangle. That is, the configuration for the arch would be 4
ft.H x 4 ft W. An interior arch 3 feet high would have an interior
base of 3 ft.
Am I wrong in my understanding of this?
John Rodgers
Birmingham, AL
Hank Murrow wrote:
> On Wednesday, April 16, 2003, at 07:13 AM, Steven D. Lee wrote:
>
>> I was wondering if anyone knows the approximate layout of Arch No. 1,
>> Arch No 2. and straight bricks needed to create a catenary arch
>> between 3 and 4 foot high. If I could have this then I coudl
>> estimate the brick needed and more importantly the cost for K-26
>> brick.
>
>
> Well Steven;
>
> If you are determined to build a catenary, here is a proven way.
> Purchase a nice small supply (perhaps 30) of straight brick, less #1
> arch brick (perhaps 20) , even less #2 arch (maybe only 6 of these)
> brick. Take these to your studio.
> Hang a chain (upside down) between the two points of greatest spread
> of the proposed hot face, against a piece of paper until you arrive at
> the right height/spread relationship...you have to be the judge of
> this. The chain should hang free of obstruction. Then spay paint the
> 'shadow' of the chain on the paper. Take the paper down and lay it out
> on the floor.
>
> Now, start with the straights on each side (3, maybe 4 straights)
> until you need a #1 , then place your #1. Do this on each side, then
> maybe 2 straights, then #1, then straight, then #1, straight, #1 and
> #1, then #2 etc. Try to arrange your selection of brick so that the
> curve is followed as closely as possible. You will have to improvise
> somewhat. When you have a nice looking arch, take the paper away and
> rebuild the arch on the floor again with a clean sheet of paper, or
> the other side of the first one. Now draw the exact curve of the shape
> of your bricks and build your forms from that curve.
>
> Have Fun, Hank in Eugene (well, still in LA, but heading home this
> afternoon)
>
> BTW, catenary arches fail eventually, because the sloping wall
> 'pinches' the flame at the top of the bagwall, creating a hotter
> condition there, the wall expands, pinching the flame more, and the
> wall expands, etc..........until it chokes off the space between
> bagwall and kiln wall. Just my observation, of course. takes awhile,
> but for this reason, I do not consider catenarys to be permanent
> kilns. We're talking C/10 and above here, OK Clayart? Don't want to
> start another faux cause célebre here.
>
> ______________________________________________________________________________
>
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>
Mark R.Dennehy on thu 17 apr 03
Hello,
I am going to be building a kiln this spring too !Any info you can share
would be great. If you know where to find good kiln plans I would be
grateful if you could pass it on. Do you know anything about used oil to
fire?
thank you
mark
Hank Murrow writes:
> On Wednesday, April 16, 2003, at 07:13 AM, Steven D. Lee wrote:
>
>> I was wondering if anyone knows the approximate layout of Arch No. 1,
>> Arch No 2. and straight bricks needed to create a catenary arch
>> between 3 and 4 foot high. If I could have this then I coudl
>> estimate the brick needed and more importantly the cost for K-26
>> brick.
>
> Well Steven;
>
> If you are determined to build a catenary, here is a proven way. Purchase
> a nice small supply (perhaps 30) of straight brick, less #1 arch brick
> (perhaps 20) , even less #2 arch (maybe only 6 of these) brick. Take these
> to your studio.
> Hang a chain (upside down) between the two points of greatest spread of
> the proposed hot face, against a piece of paper until you arrive at the
> right height/spread relationship...you have to be the judge of this. The
> chain should hang free of obstruction. Then spay paint the 'shadow' of the
> chain on the paper. Take the paper down and lay it out on the floor.
>
> Now, start with the straights on each side (3, maybe 4 straights) until
> you need a #1 , then place your #1. Do this on each side, then maybe 2
> straights, then #1, then straight, then #1, straight, #1 and #1, then #2
> etc. Try to arrange your selection of brick so that the curve is followed
> as closely as possible. You will have to improvise somewhat. When you have
> a nice looking arch, take the paper away and rebuild the arch on the floor
> again with a clean sheet of paper, or the other side of the first one. Now
> draw the exact curve of the shape of your bricks and build your forms from
> that curve.
>
> Have Fun, Hank in Eugene (well, still in LA, but heading home this
> afternoon)
>
> BTW, catenary arches fail eventually, because the sloping wall 'pinches'
> the flame at the top of the bagwall, creating a hotter condition there,
> the wall expands, pinching the flame more, and the wall expands,
> etc..........until it chokes off the space between bagwall and kiln wall.
> Just my observation, of course. takes awhile, but for this reason, I do
> not consider catenarys to be permanent kilns. We're talking C/10 and above
> here, OK Clayart? Don't want to start another faux cause célebre here.
>
> __________________________________________________________________________
> ____
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
Mark R.Dennehy
Hank Murrow on thu 17 apr 03
On Thursday, April 17, 2003, at 07:01 AM, Mark R.Dennehy wrote:
> Hello,
>
> I am going to be building a kiln this spring too !Any info you can
> share
> would be great. If you know where to find good kiln plans I would be
> grateful if you could pass it on. Do you know anything about used oil
> to
> fire?
> Dear Mark;
I don't build brick kilns anymore. My kiln design may be seen at
http://www.murrow.biz/hank/kiln-and-tools.htm and would be too
challenging for most to complete themselves. I also cast salt/soda
kilns with thin hardcast sections backed up with fiber, and these are
experimental at present.
I have built oil burners with good success using slot burners of my own
design and natural draft.
Cheers, Hank
Hank Murrow on thu 17 apr 03
On Thursday, April 17, 2003, at 08:02 AM, John Rodgers wrote:
> Hank, my understanding of the true cantenary arch is that the "Inside
> Base" is ALWAYS as wide as the "Inside Height" ......always! No more,
> no less.
> Am I wrong in my understanding of this?
>
Dear John;
You are right if you say your version is one example of a catenary arch.
There are as many catenary curves as may be described by hanging a
chain between two points, no matter the width or height, all are
catenary curves. I have built kilns with them up to three times as high
as wide, and also slightly less high as wide. All nine kilns failed
eventually 1/3 of the way up the curve. All were hard brick, except for
one made of castable.
Hope this clarifies, Hank
Fredrick Paget on thu 17 apr 03
I groused about this last year. Now in the boat building field there are
hundreds of nice plans - some free and some of the more compete type sold
by the author. These are mainly plans that have been drawn up by a
draftsman and give complete material lists and detailed drawings of each
step.
Why don't some of our kiln guros get together with a draftsperson and put
out kiln plans?
THERE IS MONEY TO BE MADE!
Hank, Nils, John, etc are you listening?
Fred
>I am going to be building a kiln this spring too !Any info you can share
>would be great. If you know where to find good kiln plans I would be
>grateful if you could pass it on.
>mark
From Fred Paget, Marin County, California, USA
Marcia Selsor on thu 17 apr 03
I have built them usually taller than wider. And I stack them with the
shelves tapering in as the arch tapers. Mine usually got a crack 2/3 up
the sides but didn't cause problems. I fired one 2 xs 'week for 5 years
at my school. Then we moved into a new building and I built new kilns.
Marcia
Hank Murrow wrote:
> On Thursday, April 17, 2003, at 08:02 AM, John Rodgers wrote:
>
>> Hank, my understanding of the true cantenary arch is that the "Inside
>> Base" is ALWAYS as wide as the "Inside Height" ......always! No more,
>> no less.
>
>
>> Am I wrong in my understanding of this?
>>
> Dear John;
>
> You are right if you say your version is one example of a catenary arch.
>
> There are as many catenary curves as may be described by hanging a
> chain between two points, no matter the width or height, all are
> catenary curves. I have built kilns with them up to three times as high
> as wide, and also slightly less high as wide. All nine kilns failed
> eventually 1/3 of the way up the curve. All were hard brick, except for
> one made of castable.
>
> Hope this clarifies, Hank
>
> ______________________________________________________________________________
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>
--
Tuscany in 2003
http://home.attbi.com/~m.selsor/Tuscany2003.html
Hank Murrow on thu 17 apr 03
Dear Fred;
I always listen to whatever you say, can't remember deleting one of
yours before reading. However, the kilns I am interested in are not
generic. Personally, I cannot imagine beginning the design of any kiln
without knowing what furniture is planned for it. Anyway, if I do come
up with something easily buildable by regular folk, I will publish the
plans at my web site for all to use. Thanks for the suggestion.
Cheers, Hank in Eugene
On Thursday, April 17, 2003, at 11:30 AM, Fredrick Paget wrote:
> I groused about this last year. Now in the boat building field there
> are
> hundreds of nice plans - some free and some of the more compete type
> sold
> by the author. These are mainly plans that have been drawn up by a
> draftsman and give complete material lists and detailed drawings of
> each
> step.
> Why don't some of our kiln guros get together with a draftsperson and
> put
> out kiln plans?
> THERE IS MONEY TO BE MADE!
> Hank, Nils, John, etc are you listening?
> Fred
>
>
>> I am going to be building a kiln this spring too !Any info you can
>> share
>> would be great. If you know where to find good kiln plans I would be
>> grateful if you could pass it on.
>> mark
>
> From Fred Paget, Marin County, California, USA
>
> _______________________________________________________________________
> _______
> Send postings to clayart@lsv.ceramics.org
>
> You may look at the archives for the list or change your subscription
> settings from http://www.ceramics.org/clayart/
>
> Moderator of the list is Mel Jacobson who may be reached at
> melpots@pclink.com.
>
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