Erin Hayes on fri 29 aug 97
Hello to Vince, Bob, Tony and any Clayarters who have experience with
Alpines!
I am wondering how you can tell when an Alpine goes bad. Here's the
deal...
I've been firing our college's old Alpine (called Gadget) for the three
years since I got here, about 30 - 35 firings a year, each to Cone 10 in
reduction. She has been extremely reliable, from the placement of hot
and cool spots, the slightly hotter temp on the bottom, and even at what
cone the hot layer inverts from top to bottom. I was heartily impressed
with this, since I had always fired downdrafts in grad school (and still
prefer them).
In the past few months, however, Gadget has been increasingly uneven
both from top to bottom and front to back. Even on single pieces there
can be drastic difference in temperature and reduction. Instead of sweet
spots throughout the kiln, we have a two to three shelf sweet zone, and
the rest of the kiln is strangely cold - to the point of underfired
bodies and dry glaze. The amount of refiring we are doing is inordinate.
Now, Gadget is an old girl. I understand that she got here in the mid
70's. There are large cracks in the lining, the muffle slab pockets are
shot to hell and the door insulation is baggy. I don't know what to do.
She's been a great kiln for a long time, but the quality of the firings
is really unpredictable these days! All my firing notes look
consistent, including time and temperature rise. The loading has been
consistent, and I am careful to leave space behind the shelfs to allow
drafting up the back of the wall.
What is your advice? Can we coat her gut with mortar and make any
difference? Or is it the cracks at all? I'm just about at my wit's end
and I know it will be a problem if the student work keeps emerging from
the kiln fired so unevenly - despite the cones coming out melted exactly
the same as they always have! I feel like I'm watching my kiln die
slowly!
Thanks in advance for your help.
Erin. (pounding my fists and stomping my feet because I don't know
what's going on ...)
Nils Lou on sat 30 aug 97
From your description I would do the following: Trash the flame channel
muffles! Clean any detritus (debris) and spray the interior with ITC100
including the door. After drying patch any part of the door that has
broken so it will seal well using ITC200EZ. It is important to have the
ITC100HT on as a first coat. Next, if your burners still have the lousy
porcelain burner heads remove them and again clean any debris in the
burner ports. You can either leave the burners with just the open pipe, or
if you have the time and money replace with a pipe nipple and Eclipse
flame retention head. In either case, a coating of ITC213 metal protectant
will beneficiate the new head's life.Now, line the cleaned out flame
channel with a one inch layer of ceramic fiber going the entire length and
up the back wall about five to six inches. Your kiln will now fire like
new. Nils
On Fri, 29 Aug 1997, Erin Hayes wrote:
> ----------------------------Original message----------------------------
> Hello to Vince, Bob, Tony and any Clayarters who have experience with
> Alpines!
>
> I am wondering how you can tell when an Alpine goes bad. Here's the
> deal...
>
> I've been firing our college's old Alpine (called Gadget) for the three
> years since I got here, about 30 - 35 firings a year, each to Cone 10 in
> reduction. She has been extremely reliable, from the placement of hot
> and cool spots, the slightly hotter temp on the bottom, and even at what
> cone the hot layer inverts from top to bottom. I was heartily impressed
> with this, since I had always fired downdrafts in grad school (and still
> prefer them).
>
> In the past few months, however, Gadget has been increasingly uneven
> both from top to bottom and front to back. Even on single pieces there
> can be drastic difference in temperature and reduction. Instead of sweet
> spots throughout the kiln, we have a two to three shelf sweet zone, and
> the rest of the kiln is strangely cold - to the point of underfired
> bodies and dry glaze. The amount of refiring we are doing is inordinate.
>
> Now, Gadget is an old girl. I understand that she got here in the mid
> 70's. There are large cracks in the lining, the muffle slab pockets are
> shot to hell and the door insulation is baggy. I don't know what to do.
> She's been a great kiln for a long time, but the quality of the firings
> is really unpredictable these days! All my firing notes look
> consistent, including time and temperature rise. The loading has been
> consistent, and I am careful to leave space behind the shelfs to allow
> drafting up the back of the wall.
>
> What is your advice? Can we coat her gut with mortar and make any
> difference? Or is it the cracks at all? I'm just about at my wit's end
> and I know it will be a problem if the student work keeps emerging from
> the kiln fired so unevenly - despite the cones coming out melted exactly
> the same as they always have! I feel like I'm watching my kiln die
> slowly!
>
> Thanks in advance for your help.
>
> Erin. (pounding my fists and stomping my feet because I don't know
> what's going on ...)
>
Vince Pitelka on wed 3 sep 97
At 09:32 AM 8/30/97 -0400, you wrote:
>----------------------------Original message----------------------------
>From your description I would do the following: Trash the flame channel
>muffles! Clean any detritus (debris) and spray the interior with ITC100
>including the door. After drying patch any part of the door that has
>broken so it will seal well using ITC200EZ. It is important to have the
>ITC100HT on as a first coat. Next, if your burners still have the lousy
>porcelain burner heads remove them and again clean any debris in the
>burner ports. You can either leave the burners with just the open pipe, or
>if you have the time and money replace with a pipe nipple and Eclipse
>flame retention head. In either case, a coating of ITC213 metal protectant
>will beneficiate the new head's life.Now, line the cleaned out flame
>channel with a one inch layer of ceramic fiber going the entire length and
>up the back wall about five to six inches. Your kiln will now fire like
>new. Nils
Just an additional note based on repairing the old Alpines at U-Mass,
Amherst when I was ceramics tech there. Go for the shorter burner pipe with
the Eclipse flame-retention tip, and mount the tip OUTSIDE the burner port,
rather than poking into the port as those oddball Alpine burners do. Cut
back the sheet-metal and framing to expose about one inch of refractory
around the outside of the burner port, and use some APGreeen Greenpatch-421
(or the equivalent ITC product) to affix a softbrick collar to direct the
burner flame into the small Alpine burner port. This, in combination with
the suggestions above, will make the Alpine fire BETTER than new.
- Vince
Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
1560 Craft Center Drive, Smithville TN 37166
Erin Hayes on thu 4 sep 97
Hi Vince!
Thanks for the extra burner suggestions about the Alpine. I got word
this morning that since it will be a repair job, we won't have to pay
for it, so I guess I'll be buying those Eclipse burner tips! Any ideas
on where to get them?
Erin. (rejoicing in the Vice-President's repair fund.)
Nils Lou on thu 4 sep 97
Vince makes very good points. It will fire better. NL
On Wed, 3 Sep 1997, Vince Pitelka wrote:
> ----------------------------Original message----------------------------
> At 09:32 AM 8/30/97 -0400, you wrote:
> >----------------------------Original message----------------------------
> >From your description I would do the following: Trash the flame channel
> >muffles! Clean any detritus (debris) and spray the interior with ITC100
> >including the door. After drying patch any part of the door that has
> >broken so it will seal well using ITC200EZ. It is important to have the
> >ITC100HT on as a first coat. Next, if your burners still have the lousy
> >porcelain burner heads remove them and again clean any debris in the
> >burner ports. You can either leave the burners with just the open pipe, or
> >if you have the time and money replace with a pipe nipple and Eclipse
> >flame retention head. In either case, a coating of ITC213 metal protectant
> >will beneficiate the new head's life.Now, line the cleaned out flame
> >channel with a one inch layer of ceramic fiber going the entire length and
> >up the back wall about five to six inches. Your kiln will now fire like
> >new. Nils
>
> Just an additional note based on repairing the old Alpines at U-Mass,
> Amherst when I was ceramics tech there. Go for the shorter burner pipe with
> the Eclipse flame-retention tip, and mount the tip OUTSIDE the burner port,
> rather than poking into the port as those oddball Alpine burners do. Cut
> back the sheet-metal and framing to expose about one inch of refractory
> around the outside of the burner port, and use some APGreeen Greenpatch-421
> (or the equivalent ITC product) to affix a softbrick collar to direct the
> burner flame into the small Alpine burner port. This, in combination with
> the suggestions above, will make the Alpine fire BETTER than new.
> - Vince
>
> Vince Pitelka - vpitelka@DeKalb.net
> Home 615/597-5376, work 615/597-6801, fax 615/597-6803
> Appalachian Center for Crafts
> 1560 Craft Center Drive, Smithville TN 37166
>
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