Marcia Selsor on tue 10 dec 02
I dislike brick up doors because they hurt my wrists over many years BUT
to answer your questions...
!. The bricks can be stacked within the door or in a locking system of a
course inside the door and one on the outside of the door.
Your floor should be designed to accomidate whatever style door you
intend to use.
2. To stack under the arch, usually one has cut small shaped to fit into
the space under the arch. If you have the second stack of the door on
the out side, this provides a good seal.
3. Stack really tight and mud up the cracks. I used some cellulose that
I used for paper clay, mixed with ash and sand and bonded together with
clay. It insulates pretty well also.
Marcia in Montana
Tuscany in 2003
http://home.attbi.com/~m.selsor/Tuscany2003.html
Lynne Kay on tue 10 dec 02
Hello ClayArters
I've never seen a brick up door in real life before, so I am curious. =
Does the brick up door go up on the outside of the kiln, overlapping the =
kiln wall. If so does it require some sort of bracing?
Or=20
Does the door brick up in line with the kiln wall? If so, how do you =
get the last ones in? What about the arch?
Thanks
Lynne Kay
vince pitelka on wed 11 dec 02
I believe strongly in hinged kiln doors or roll-up kiln doors, but sometimes
a stacking door is the only reasonable option, especially for someone
building their first gas or wood kiln.
I wanted to mention one of the best tricks to use if you must have a
stacking door. When you build the arch form for your kiln, also build a
narrow "rack" of the opposite curvature, perhaps a curved piece of masonite
well supported with backup ribs - built just like the arch form, but with
exactly the opposite curvature, and just wide enough to store the door
bricks when you unstack the door. If your door is two bricks thick, which
is the norm, make this rack 9" deep. Place it off to the side in front of
your kiln where you won't have to move the bricks very far, or better yet,
mount it on very sturdy caster wheels. When you remove the custom-shaped
bricks from the top of the door, invert them and lay them in this curved
rack. That way they will stay exactly in order. If you have a sprung arch
kiln, then this rack need only accommodate the bricks that fill the arched
space a the top of the door. The rest of the bricks can be stacked any old
which way. But if you have a catenary arch kiln, the rack needs to
accommodate the entire door, since there are custom fit bricks in every row.
In either case, it will help to have a back board on back side of the rack -
just a sheet of plywood, that the bricks but up against. It makes it easier
to stack them in the rack, and decreases the chances of the pile falling
over if someone bumps into it.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://iweb.tntech.edu/wpitelka/
John Kimpton Dellow on wed 11 dec 02
Lynne Kay wrote:
>
> Hello ClayArters
>
> I've never seen a brick up door in real life before, so I am curious. Does the brick up door go up on the outside of the kiln, overlapping the kiln wall. If so does it require some sort of bracing?
For a start the bricked up entrance to a kiln is a wicket ,not a
door . A door is
on hinges .
> Or
>
> Does the door brick up in line with the kiln wall? If so, how do you get the last ones in? What about the arch?
The is best place in the wall which is formed by the arch not
that which supports
it. It usual to make it just wide enough for the largest pots one
makes.
John Dellow "the flower pot man"
Home Page http://www.welcome.to/jkdellow
http://digitalfire.com/education/people/dellow/
Snail Scott on wed 11 dec 02
At 03:45 PM 12/11/02 -0600, Vince wrote:
>You are wise to mention the importance of overcoming that lean, but it could
>never be caused by reduction pressure. The simple truth is that the bricks
>get hotter on the inside, expanding more than the bricks on the outside, and
>thus cause the upper part of the door to lean outwards...
Good point, Vince. That hot-face expansion can
be significant, and I should have mentioned it.
I still think pressure can cause some of the
effect, but having reconsidered, I think you're
quite right, and it's the expansion differential
that's mostly to blame.
-Snail
Snail Scott on wed 11 dec 02
At 02:42 PM 12/10/02 -0600, you wrote:
>I've never seen a brick up door in real life before, so I am curious. Does
the brick up door go up on the outside of the kiln, overlapping the kiln
wall. If so does it require some sort of bracing?
>Does the door brick up in line with the kiln wall? If so, how do you get
the last ones in? What about the arch?
Personally, I like 'em to fit inside the walls of the kiln,
rather outside than against the ends of the walls. It's easier
to stack on the outside, since the rows can be any approximate
length and the shape/height of the top row doesn't matter.
With an inside-stacked door, you have to spend a lot of time
fitting the bricks. After you've done it once, take down the
door systematically, and stack the bricks by row, so the next
time you fire, they're all waiting in the right order. For a
catenary or sprung-arch, you may have to cut or break bricks
to fit the top, and sort of slide or wedge them into position.
An inside-fitted door can easily be made to lean slightly inward,
offsetting the tendency of reduction pressure to force it outward,
while an outside-stacked door would need a slight angle to the
wall-ends to make this work well. Also, when that interior
pressure does force the door to bend slightly outward, the crack
around an inside-stacked door stays constant in width. An
outside-stacked door will have a wedge-shaped gap open up along
the wall as pressure increases.
Also, I like to do double-thick doors for high-fire, and chink
any gaps with clay...it makes a BIG difference!
-Snail
vince pitelka on wed 11 dec 02
> An inside-fitted door can easily be made to lean slightly inward,
> offsetting the tendency of reduction pressure to force it outward,
> while an outside-stacked door would need a slight angle to the
> wall-ends to make this work well. Also, when that interior
> pressure does force the door to bend slightly outward, the crack
> around an inside-stacked door stays constant in width. An
> outside-stacked door will have a wedge-shaped gap open up along
> the wall as pressure increases.
Snail -
You are wise to mention the importance of overcoming that lean, but it could
never be caused by reduction pressure. The simple truth is that the bricks
get hotter on the inside, expanding more than the bricks on the outside, and
thus cause the upper part of the door to lean outwards. This lean tends to
be far more pronounced with a hardbrick stacked door, but the disadvantage
of a softbrick stacked door is that the bricks tend to erode quickly from
stacking and unstacking.
You are generally a fount of wisdom and truth, but I felt I should correct
this.
Best wishes -
- Vince
Vince Pitelka
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166
Home - vpitelka@dtccom.net
615/597-5376
Work - wpitelka@tntech.edu
615/597-6801 ext. 111, fax 615/597-6803
http://iweb.tntech.edu/wpitelka/
Ned Ludd on thu 12 dec 02
Clayarters,
I am resending this post after it didn't show up by this evening. If
you already got it somehow, please delete.
>At 02:42 PM 12/10/02 -0600, somebody wrote:
> >I've never seen a brick up door in real life before, so I am curious. Does
>the brick up door go up on the outside of the kiln, overlapping the kiln
>wall. If so does it require some sort of bracing?
>>Does the door brick up in line with the kiln wall? If so, how do you get
>the last ones in? What about the arch?
and Snail wrote:
>Also, I like to do double-thick doors for high-fire, and chink
>any gaps with clay...it makes a BIG difference!
When a potter takes more trouble to get the kilnbrick door (or
'wicket' as John Dellow in Oz points out) cut to fit the arch, it
does not mean the firing results will get better. This is the case
with us, using a feisty gas oldie, 18 cu ft., regular trips to cone
eleven, with a wicket of twenty courses of softbrick, top to bottom.
The bricks go up outside the arch, abutting it and not snug under it.
Sides of the wicket, left and right, fit just within a vertical angle
iron L-frame bar, which defines the loading door, about three feet
wide.
I use a white stoneware body. My firings to cone ten have been good
and getting better. But my much more kiln-experienced studio
partner's firings to cone eleven are even better, technically. By
this I mean heat evenness, no hiccups, consistency and predictability
of firings and the quality of his pots (porcelain, copper reds
predominant). By endfire, his cones fall in perfect time at top and
bottom, whereas I am satisfied to have them end up only a cone apart.
ie, hard cone ten at top, cone nine over on bottom. I find that hard
enough!
Our wicket is only one brick thick, (four inches), and we do not plug
chinks with clay. The only plugging we do is at the top of the
wicket, with fiber. When I started firing this kiln I plugged my
chinks religiously, thinking it would improve things. Everybody said
so, after all. ;->
My firing-savvy studio partner never does plug those chinks, and soon
I followed suit. I noticed no unwanted effect. Another old potter's
tale bites the dust, perhaps? Not necessarily: if our gas supply were
lower pressure, our no-plugging policy might not help. In fact our
piped gas supply is very powerful, designed as it was to fire several
kilns at the same time (now it need fire only this one, and heat the
pottery too). Not clamming, for us, does help, I think. How might
this be? Maybe the secondary air coming through the chinks in our
bricked up door is a plus and not a minus. Here's why I think so: our
kiln has four small burner ports that don't let in a great deal of
secondary air around the burner heads. The sides of the kiln are
sheathed in board, so there - and at top and bottom - it does not
'breathe' much, further lessening the available secondary air. An
oxidation or even neutral atmosphere as we fire higher soon gets
impossible. We are in moderately heavy reduction all the way from the
body reduction stage to end of the firing. No other way around it,
for us. Any air we are getting through our chinky door actually
helps, I believe. Its tendency to hamper temperature rise is overcome
by the power of our burners.
I am still learning my kiln lore and if I err in my understanding, I
ask wiser potters to enlighten me!
best
Ned
Gail Dapogny on thu 12 dec 02
Vince said--
>The simple truth is that the bricks
>get hotter on the inside, expanding more than the bricks on the outside, and
>thus cause the upper part of the door to lean outwards. This lean tends to
>be far more pronounced with a hardbrick stacked door, but the disadvantage
>of a softbrick stacked door is that the bricks tend to erode quickly from
>stacking and unstacking.
I have been bricking and unbricking the doors on two sizeable gas kilns for
over 25 years, and I would gladly abandon the chore for real hinged steel
doors! It is a dusty, back-breaking chore when the kiln is large, and
unfortunately it comes at the end of hours of stacking. Takes about an hour
to brick up our 90 cubic foot kiln, 30-45 minutes for the 60 cub ft (which
we bisque in).
Having said that--- we use soft bricks -- both regular-size and wedges--
and build up the door including 4 vents total, plus a peep through which to
view the cones and to gauge the reduction flame. We insert the bricks long
way so they are equivalent in depth to two rows, in and out, of bricks.
They fit between the sides of the front wall. There is an arch so it
requires bricks cut and rasped to fit. At the end, we "caulk" with
stoneware -- quite a lot of it. (I'm interested in Marcia's mixture.)
Even taking the trouble to brick tightly, when we get to the high temps, I
see an awful lot of spaces. Discouraging. And no help to clower cooling,
I'm afraid.
On top of that, these bricks, as Vince mentioned, erode and break (and we
do coat them, which helps). Re-doing the arch is a pain in the butt.
Incidentally do you tool wizards think that a jig saw could handle brick
sawing? I haven't tried anything other than hand-sawing --ugh--and
rasping. I am open to any and all suggestions, especially the miraculous
ones.
---Gail
Gail Dapogny
1154 Olden Road
Ann Arbor, MI 48103-3005
(734) 665-9816
gdapogny@umich.edu
http://www.silverhawk.com/ex99/dapogny (single historical photo - no longer
registered with Silverhawk)
Steve Mills on fri 13 dec 02
The brick-up door on one of my previous kilns was assembled inside the
arch. The answer to the last question is: VERY CAREFULLY! Seriously
though the bricks were followed up with wedges which held them in place,
then the whole mortared over with a mixture of equal parts of old door
mortar, scrap clay, sand, and sawdust. Later I cast 6 blocks with
handles on the outside; quicker to put up than umpteen bricks!
Steve
Bath
UK
In message , Lynne Kay writes
>Hello ClayArters
>
>I've never seen a brick up door in real life before, so I am curious. =3D
>Does the brick up door go up on the outside of the kiln, overlapping the =
>=3D
>kiln wall. If so does it require some sort of bracing?
>
>Or=3D20
>
>Does the door brick up in line with the kiln wall? If so, how do you =3D
>get the last ones in? What about the arch?
>
>Thanks
>Lynne Kay
--
Steve Mills
Bath
UK
| |
|
