mel jacobson on sun 3 jul 05
i am going to give some examples of
things talked about at hay creek this
summer about cones. several long discussions.
tim frederich as many of you know worked
at orton for about 10 years...he knows a bit about
cones.
angle.
the box has a template that shows how the cones are
suppose to be placed in the holder. about 10 degrees in angle.
if you change that.. be consistent...some like 20 degrees...
one of our friends likes 30.. he always does 30 so he has
learned to read it. it is so much about consistency. a thirty degree
cone reads about a half cone cold.
you learn over time to read your cones like you read your
kiln. you understand it. old time firing folks learn to
trust their consistent cone placement. never question it.
if the cone says 6....it is 6.
placement.
away from direct flame, and back on the shelf is best.
but again....place the cones in the same place for your
viewing pleasure....if you read from the third peep hole,
make sure it is always in the third peep.
consistent viewing..same place each time you fire.
that way you always get the same stuff happening.
in a fuel kiln...it is very important to have one cone that you always
trust. same place...cones can do funny things in a fuel kiln. you have
to have one you trust above all others. (same for life.)
viewing.
if you blow on your cones every time you open the kiln...maybe
10 times over the last hour...you can freeze the cone. you are
blasting it with cold air. try not to blow a great deal. also gets
crap on your pots...the peephole is usually full of crap.
welding glass is great. dark lenses of any kind will help you.
just buy the glass part of an arc welding hood. about a buck.
buy them in three or four strengths...any welding place has them.
just hold them up to the sun...see what you like.
back ground.
a dark flat iron coated background is best for viewing cones.
remember, glazes get glossy in a kiln, reflect light. a flat surface
will aid you in seeing. it will not affect the pots. keep it small, about
2x4 inches with a tiny base. use if a few times over. it can be thin.
adding iron to the cone.
it works, but you must be very consistent, as it changes the value
of the cone. it could be as high as a half cone difference. if you
learn to read that colored cone/it will work. just make sure you know
what you are doing. orton does not recommend you slather stuff on
cones.
many potters make very interesting cone packs. some use three cones.
some will add a cone 011 in the front of the pack with a small catcher for
the runny cone. (reduction time.) shino folks love that technique.
you could build a tiny wall
behind the cones and coat it with iron...how you create a cone pack is up
to you. some hollow out a piece of soft brick..use it over and over...i like
a solid base of clay...(always allows you to read not just the cone when
done, but clay color as well.) one can make them large or small, elaborate
or simple...just make sure that you trust what you do.
a cone is the safest, cheapest single thing you have as a firing potter.
use them...waste them...don't get cheap with cones. add them all
over your kiln if you are having trouble. see what is going on inside
the kiln during the firing. it is like reading a book.
this year before hay creek, kurt and i sat for an hour making cones.
we knew if the wood kiln was going to fire...we needed cones.
we did about 30 sets. 10, 11, 12. then a series of cone 9,10 for the salt
kiln. put them in the sun, ready for the gang. (used the 10,11,12 for the
iron saga firings.)
i like to make about 40 sets and put them in the window of my studio.
ready to go. i use three packs for each firing. same place every time.
i read the cone in the front, middle..next to the oxyprobe and thermocouple.
then they are all in the same place for every firing. three inches between
them. one cone pack on each side. this helps me read if the kiln is lagging
on one side or the other. i can turn up a burner and move the heat if
that happens. but, i always turn off the kiln based on that front cone.
when are you done?
when the cone bends over and touches the shelf.
just the tip.
of course some like to read half way. i don't. tim fires the cones
to touch the kiln shelf. i follow that lead...always have.
it is so easy to read. but each potter picks a bend of the cone.
reads it their own way. and that is best.
just remember, trust your cones. pyrometers do not tell the story.
they are just a guide. my oxyprobe is pretty accurate...but i don't trust
it. cones...your best friend.
mel
from mel/minnetonka.mn.usa
website: http://www.pclink.com/melpots
bonnie staffel on mon 4 jul 05
thanks for the Primer on this subject, Mel. However, to clarify my use of
iron on the edge of my cones, I do not "slather" the iron on, but use either
my finger dipped into the dry iron oxide and just touch the edge, not the
face of the cone. Or I may use my signing brush wiped of most liquid and
just touch the edge, not the face, and that gives a very clear vision
through the peep hole as I place the three cones with the edges toward the
peep holes. No blowing required. Depending upon one's eyesight, dichroic
glasses are good, but to put them on top of one's regular bifocals makes
contortions a real sight to behold when trying to bend/squat down to that
middle peep, the lifting one's head so you can see out of the bifocal. I am
sure some of you "same age" potters can laugh at this one.
I have a terrific large L&L DaVinci. The only problem I see in it is that
they put the peep holes dead center in the front wall right where the posts
go. I have to offset the posts so the cones can be seen. I think that L&L
saw the folly of this position and the peeps are placed off to the side a
bit now. I like the square/rectangle shape of this kiln as it holds a lot
of large round work. Corners are great for the stacking operation.
Regards,
Bonnie Staffel
http://webpages.charter.net/bstaffel/
http://vasefinder.com/bstaffelgallery1.html
Charter Member Potters Council
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