Sara Laitala on thu 8 sep 05
Dear folks- I've been helping a friend fire her 30 year old crossdraft kiln
and we're having some trouble with a peep that has grown over time so that
our peep brick is too small for the hole. We've tried sticking a wedge of
soft brick unto the peep brick with kiln cement to fill the gap, but the
wedge falls off after the first couple of looks into the kiln. This leaves
us with a fire breathing dragon of a peep hole around the too small peep
brick. Any suggestions will really be appreciated.
thanks-Sara Laitala, Okemos, Michigan
Rikki Gill on thu 8 sep 05
Hi Sara,
Electric kilns sometimes use long tapered cone shaped peep covers made of
soft brick. I use one backwards, I insert the wide end as far as it will
go, and the small end can be removed easily as it extends out. I have used
the same one for years now, and I fire to cone 11.
Hope this helps.
Rikki Gill
----- Original Message -----
From: "Sara Laitala"
To:
Sent: Thursday, September 08, 2005 7:52 AM
Subject: peep brick problem with aging gas kiln
> Dear folks- I've been helping a friend fire her 30 year old crossdraft
kiln
> and we're having some trouble with a peep that has grown over time so that
> our peep brick is too small for the hole. We've tried sticking a wedge of
> soft brick unto the peep brick with kiln cement to fill the gap, but the
> wedge falls off after the first couple of looks into the kiln. This leaves
> us with a fire breathing dragon of a peep hole around the too small peep
> brick. Any suggestions will really be appreciated.
> thanks-Sara Laitala, Okemos, Michigan
>
>
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>
Lester Haworth on thu 8 sep 05
Hi Sara,
This is a simple fix. Remove the bad brick with an old hacksaw blade. Do it
slowly as the hacksaw blade cuts soft brick like butter. Form the new
peephole with a keyhole saw kit and a drill. Again go slowly as new brick is
also fragile and very prone to chipping. You can either chisel or router the
old brick away. (about an inch in depth) and install new brick over the old
brick. Pre-cutting the brick and placing the brick in place before using the
mortar is crucial to the success of your project. If your satisfied with how
it looks then apply the mortar. Use smooth set mortar and allow to dry for a
full day before firing. Sand down any excess brick after the mortar has
dried. Doing a quick preheat or candleing (30 - 45 min.) before you fire
your first load will help cure the mortar if needed. To see a sample of this
technique go to http://www.mobilekilnrepair.com/pages/CasaAfter.html for a
nice picture of some surface repairs I've done to a 12 cu. ft. gas kiln.
Enjoy,
Lester R. Haworth III
Sales and Technical Support
Laguna Clay Co.
14400 Lomitas ave
City of Industry, CA 91746
(626)330-0631 ext. 229
les@lagunaclay.com
www.lagunaclay.com
"Once you can accept the universe as matter expanding into nothing that is
something, wearing stripes with plaid comes easy." ~~ Albert Einstein
-----Original Message-----
From: Clayart [mailto:CLAYART@LSV.CERAMICS.ORG]On Behalf Of Sara Laitala
Sent: Thursday, September 08, 2005 7:52 AM
To: CLAYART@LSV.CERAMICS.ORG
Subject: peep brick problem with aging gas kiln
Dear folks- I've been helping a friend fire her 30 year old crossdraft kiln
and we're having some trouble with a peep that has grown over time so that
our peep brick is too small for the hole. We've tried sticking a wedge of
soft brick unto the peep brick with kiln cement to fill the gap, but the
wedge falls off after the first couple of looks into the kiln. This leaves
us with a fire breathing dragon of a peep hole around the too small peep
brick. Any suggestions will really be appreciated.
thanks-Sara Laitala, Okemos, Michigan
____________________________________________________________________________
__
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.
John Baymore on thu 8 sep 05
Sara,
I am assuming theat the spy port is in a soft brick wall? Not sure if
this is the problem with your "repair" job or not that keeps "failing"...
but a suggestion hides in here that is oft "overlooked":
Take the spy port brick out of the old spy hole. Pick out the big chunks
of old failed "repair". Take a bucket of water and a big sponge and
TOTALLY ...and I mean totally... soak the whoe area of the spy port. Chip
off the old mortar mess. Try to square up the hole as much as possible.
Take an old hacksaw blade and cut some 1/8" deep grooves sort of randomly
around the interior of the faces of the existing brickwork maybe 1/2"
apart...it's not too critical for spacing.
Now with the area still very wet, take and clean out every scrap of
old "junk" and brick crumbs and dust that is accumulated there. Be
CAREFUL about the dust... this is laden with sub-micron crstyaline
silica .... really BAD stuff to breathe... and it will stay in the air in
the kiln room for days unless you have good ventilation (which you SHOULD
have anyway ).
Measure the general size of the hole. Decide on the size that you want
the repaired spyport to be. That will allow you to figure out how thick
the laminations need to be to apply to the inside of the existing hole.
If the laminations are less than about 1/2" thick...... you likely want to
enlarge the hole in the wall so that they ARE at least that thick.
BTW...... sometimes is is easier to just replace whole brick module
structures.
Inside the existing hole, the side wall lamination repair sheets need to
support the top lamination spanning it, and they both sit on top of the
bottom one that goes the whole width of the hole too. So measuere
appropriately for cutting the right size pieces. And subtract about 3/16"
for the thickness of the mortar that will be in there too. Plan ahead .
Get a single 2800 rated IFB to cut the repairs out of. Much stronger
physically than 26 or lower rated brick..... but harder to cut too .
Use a treee pruning bow saw to cut the new laminations. This hard surface
will help resist the friction wearing that is prevalent in so many IFB
spyports.
Get yourself whatever variety of combination air AND heat setting bonding
mortar that you prefer or have available from your suppliers. ITC 100 HT
will work in a pinch... but it is too expensive to use unless you just
have some leftover already on hand. Don't use a home-made fireclay and
sodium silicate "potter remedy".
Now once again SOAK the whole area of the repair. If you don't do this
step, the bonding mortar will have the liguid sucked out of it into the
softbrick "sponge" almost instantly, and it will not bond to the
surrounding brick correctly. This is KEY to real success.
Trowel on a 1/8"-ish thick coating of cement on the bottom laminate and
the bottom of the hole and then press the piece into place with a wiggling
motion back and forth. The mortar should readily ooze out of the
sides.....just clean it off afterwards. Then do the same for the two
sides, and then last the top. The top might be a tigh "slid in" job. You
may have to shave the brick if you got the mortar thickness allowance
wrong in the cutting stage .
Now take a much thinner mix of the mortar (dilute with a TAD of water) and
lightly surface the entire inside of the new spyport with it. Do a very
craftsperson like job. Smooth and even. NOT thick.
Let it all dry without a brick in it closing it off for at least a couple
of days in dry weather before firing the kiln to peak temperature. On the
first peak temp firing....... use a spyport plug brick that is only
inserted shallowly into the outer part of it to let the heat penetrate a
bit further out toward the cold face than normal.
Hopefull this is of help.
best,
..................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
JBaymore@compuserve.com
http://www.JohnBaymore.com
"PLease use compuserve address for any direct communications."
Sara Laitala on thu 8 sep 05
Thank you John and Lester for the tips on reducing the size of the "peep
hole" in our old kiln. It is a soft brick wall, and the peep hole was in
earlier years equal in size to the peep brick that slides into it. We
hadn't even thought of applying laminations to return the port to it's
original size! We overlooked the obvious and were trying to make a bigger
peep brick by cementing a piece of soft brick to it. It is the little piece
of cemented on soft brick that breaks off the peep brick as it is pulled
out to check cones. We'll sure give this a try to make the peep hole
smaller. Thank you so much for the help.
gratefully- Sara
John Baymore on thu 8 sep 05
Sara,
You are welcome.
The thermal shock from taking the spy port plug in and out at temperature
was not helping your cause of keeping the patch on the plug . That was
inducing a lot of expansion / contraction stresses on the join between the
two....because the mortar and the bricks will have slightly differing
COTE's. Patching the HOLE will likely give you better long term results.
best,
................john
John Baymore
River Bend Pottery
22 Riverbend Way
Wilton, NH 03086 USA
JBaymore@compuserve.com
http://www.JohnBaymore.com
"Please use compuserve address for any direct communications."
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