Mel Jacobson on mon 19 jan 98
some points to consider, esp. after a curly ,red headed student
slams you. gosh, some people. (i never do a thing like that)
1. slide your damper in until you have a flame/backpressure at your
highest spy hole. maybe three inches/ and it should be colored/yellow more
than likely.
2. if you can, reduce the amount of primary air to your burners, take away
some of the blue color of the flame and make it almost yellow.
3. save some gas pressure/do not have your burners on full during this
time. if possible.
Now:
you can adjust any of these factors to get more or less reduction.
1. if you leave all settings the same, and then turn up the gas pressure,
you will get more reduction.
2. if you slide the damper in farther, you will get more pressure and
the flame will grow in the spy hole, hence more reduction.
3. if you take away more oxygen at your primary source the flame will get
more dirty and add reduction.
you need not have flame coming from every portal in the kiln...that is just
a great waste of fuel, and sometimes does not improve reduction.
it is the balance that you want....you should have no smoke from your
stack...it should be clean. (your neighbors should never know that you are
firing.)
weather, wind, snow...all will change the balance of your kiln..that you
must learn. watch, observe, and make simple notes. you do not have to
chart the history of the western world...just make notes.
Now:
if your kiln is hot on the top/lower your gas
if your kiln is hot on the bottom/increase your gas. or reverse this if
not true for your type kiln.
if you have two burners, learn to increase one, decrease the other,
watch the heat move across your kiln.
as i have said many times on clayart....most people fire with too much gas.
save power for the end of the firing when you may need to get that last 50
degrees. and i am sure if you get things humming, you will not need it.
a well balanced firing will just zip to cone 12 before you know it.
i have a low pressure house system for my gas. run a 25 yard gas line
underground from my house...so it is very simple...use old `denver fire
clay` natural air burners that are 40 years old. even marc ward laughed
and said` how the hell do you make temp`?
but you take a nice flat top, 15 foot 12 inch stack....45 cubes....
and fire it right....you do not need gobs of gas...in fact `gobs of gas
a great firing do not make.`
i have a rule:if your kiln is not doing what you want...change something.
turn up the gas, turn down the gas. turn up one burner, open the flue,
close the flue, turn up primary air, turn down primary air...
DO SOMETHING.
and do not fire by your notes. listen to the kiln, smell the kiln, hear
the kiln, feel the kiln.
get a welding goggle glass and look inside...see the shine on the pots.
remember they are `never` as shiney as they appear in the kiln. and if the
kiln is clear and you can see everything...no reduction.
if you cannot turn down your primary air at the burner...use light
aluminum, or foil...make a cover for the back of your burners.
i feel that air reduction at the burner is very important to good, medium
reduction. during the 70's, to save fuel, i never shut back my air...did
it all at the damper...pots where not nearly as nice...have gone back
to shutting down air....the color and speckles are back, better than ever.
i have felt that having low gas pressure has been a blessing for me.
it has taught me to use the entire kiln....i do not just pour on the gas.
that is why i never chart my gas use...it is too low.
about 6 bucks....not even the cost of a mug.
my gas bill is lower than my two adjoining neighbors. that is a fact.
and they do not own a kiln.
so....that is all i can tell you for now.
if you have questions....post me in private.
mel/mn
http://www.pclink.com/melpots
Lisa P Skeen on tue 20 jan 98
Mel:
The damper on the kiln I use is a piece of broken kiln shelf over a
chimney hole on top of the kiln. When you say, "slide the damper in", do
you mean to close or open the damper?
Lisa Skeen, Living Tree Pottery and Soaps
http://www.uncg.edu/~lpskeen
>1. slide your damper in until you have a flame/backpressure at your
>highest spy hole. maybe three inches/ and it should be colored/yellow
| |
|
