KARS Ceramics, Arts & Crafts Club

Pouring and Firing Instructions

 

Care of Molds and Pouring

 

All KARS members must have a pouring lesson before using club molds.  Arrangements for your pouring lesson are scheduled by the person designated for that job.  Molds are not to be taken out of the clubhouse under any circumstances.  If you find a damaged mold or accidentally damage one, be sure to bring it to the attention of the mold chairman.  Damaged molds will be brought to the attention of the Board and they will decide on the action to be taken.

 

Molds are to be poured only once a day.  Allow 24 hours between pourings.  This will ensure that our molds will not be abused.  Some larger molds require more than a day to dry, so if a mold is damp from previous pouring, do not pour until dry.  Never clean the mold with water or a damp cloth.  If poured correctly there wonπt be much clean-up.  After you have poured a mold, be sure that the inside and outside of the mold are clean.  A card is provided for each mold for members to write the date and time that the mold was poured.  Sign the card, and put the mold back on the shelf in the proper designated place.  Make sure the right card is on the right mold.

 

Straps and rubber bands are required on molds, for proper use and care of mold, be sure the straps and bands are on the mold when pouring and when you put the mold back on the shelf.

 

To facilitate locating a mold there are finished samples of pieces made from club molds in the meeting room.  The number on the piece corresponds with  the shelf number of the mold.  There is a loose leaf notebook in the Meeting Room that explains where all molds are located.

 

When you have finished pouring, please sweep and wipe up any slip that may have been dropped on tables, chairs, floor and etc. Keep sink free of slip because we have a septic tank and it would be costly to have the tank cleaned.

 

Firing

 

No one can fire the kilns at KARS unless they are a member and have participated in a firing lesson conducted by the club.  If you wish to schedule a lesson or have any questions, contact the person designated for the job.

 

There is a firing calendar posted in the pouring room where members sign up to fire.  You may sign this calendar (name and phone number) for firing not more than once a month.  Do not sign up to fire and have someone else fire for you.

 

If you have a piece to be fired, place it in the cabinet designated for firing and fill out a slip denoting the date, your name, name of the piece, and which firing you want (04, 05, 06, etc.) also any information as to type of glaze (red, green or crystal).  Mark your ceramic greenware with your initials or any identifying mark which indicates the item belongs to you.

 

When you fire, log all items in the log book which is located in the credenza in the firing room.  Do not fire just for yourself – take as many pieces as possible out of the cabinet to fill the kiln and fire to the applicable cone.  Turn on exhaust fan on wall when you begin firing and leave on until you unload kiln.

 

Please walk carefully in the firing room.  If someone is firing any vibration may cause a piece to fall or perhaps a shelf to fall in the kiln.  Be sure to check firing instructions for that particular kiln on firing room wall.  Make sure to check the pyrometer this is very important.  Never go outside of the ceramic building while the kiln is on.

 

Never open the kiln for any reason until the kiln is completely cooled down.  The kiln can be opened 24 hours after use  (for example: if the kiln turned off at 4:00 P.M. Tuesday, it may be opened at 4:00 P.M. Wednesday).

 

 

 

INSTRUCTIONS FOR FIRINGS

 

Greenware

 

1. Greenware to be fired again (that is, to be glazed) should be fired to cone 04 "Normal Bisque" or 03 (Hot for dinnerware).

 

2. Greenware not to be fired again should be fired to 05 or 06. That will make it "Soft Bisque" which more is more absorbent and easier to paint. NOTE: Always fire the item from Greenware to Bisque at least two cones hotter than the Glaze will be fired. For instance, it your Glaze instructs you to fire at 06, make sure your Bisque is fired at 04. This will prevent bubbles in your glaze from unreleased impurities in your Bisque.

 

3. Greenware should be dried for 3 days, longer for larger pieces.  Wet greenware may crack during firing or explode causing damage to other pieces.

 

4. Hands should be clean and free of oils while handling pieces.

 

5. Sets should be fired in the same load (canisters, dishes, bookends, etc.).

 

6. Greenware that is used together such as a box and lid should be fired together.

 

7. Plates, ashtrays (flat low pieces) should be placed on shelves in the middle of the kiln not on the bottom.

 

8. Greenware may touch, with the exception of pieces with under glaze or one strokes on them.  If they touch, the paint may rub off.

 

Glazed Pieces

 

1. Glazed pieces must be stilted and not touch one another, or they will adhere to the shelf or each other.

 

2. Leave at least a fingerπs width between pieces, sometimes colors will ≥jump.≤

 

3. Follow the instructions on your jar of paint for the proper cone at which to fire.

 

4. Red glazes should never be fired in a kiln with greenware or green glaze.

 

5. Crystal glazed pieces should be kept away from other pieces as the crystals pop during firing and will get on other pieces.

 

6. If glazed pieces are dry footed (all glaze wiped off the bottom) they may sit on the shelf without stilting.

 

     Loading the Kiln

 

1.    Check the inside of the kiln for dust, brick particles, etc. and vacuum if necessary. This is especially important before a glazed load.

 

2.    When loading the kiln, do not pack it too full.  It is a bad habit to stack things inside of each other, on top or in any combination to save space.  Too much of this and the stress caused may result in cracked bisque.

 

3.    Greenware plates, bowls, saucers may be fired top to top.  Greenware cups may be top to top with handles opposite. (Glazed pieces will fuse together if touching.)

 

4.    Greenware such as pitcher and bowls should not be fired one in the other (flat clay on flat clay) as this causes an airlock and dark spots on the piece.

 

5.    Choose posts tall enough to have at lease 2 elements between shelves.  The shelf should be 1 inch above the tallest piece.

 

6.    Place posts in a triangle, avoid putting a post near the kiln sitter.  (a kiln sitter is an electrical switch which is turned on by hand and turned off by the action of a cone bending under the rod).  Although an automatic kiln sitter does turn off the kiln, it is a mechanical device and cannot be considered an absolute guarantee against over firing.  There fore it is important to check the pyrometer for the correct temperature.  If it goes more then 25 degrees over the correct temperature, turn the kiln off manually.

 

7.    Place pieces on the shelf carefully, using stilts on glazed pieces.  Keep the pieces at least 1 inch from the wall of the kiln.  If pieces touch an element both will be damaged.

 

8.    When adding a shelf to the kiln, hold it by the edges and lower it carefully onto the posts, avoiding the sides, kiln sitter and pyrometer.  Be sure shelf is stable.  Build shelves up to the sitter.

 

9.    Inserting Cone:  The most important item that goes into the kiln is the cone.  It merits careful placement and sufficient space in planning your load.  With one hand, move weight to upright position, push down on the lever with thumb.  (lever is holding weight up.)  With the other hand hold cone number side toward you, flat side down, slide cone under sensing rod and hold.  Cone sits on T-bars.  Release thumb gently allowing rod to rest on cone.  Cone should be centered under sensing rod.  Release hold on cone gently so it remains in position.

 

10. Continue loading kiln placing posts on triangles as previous shelf.  Pieces should be one inch from top.

 

Firing

 

1.     Lid should be propped open, insert plugs in peep holes leaving top hole open.

 

2.     Set the timer (if the kiln has one) for a little longer than you expect the firing to take.  Push in plunger all the way.  The plunger will not go in if the timer is not set.

 

3.     Starting at bottom switch, turn to low, pause and turn next switch to low, continue same manner to remaining switches.

 

4.     Fire on low for 1 hour.  During the low, the moisture is being taken out of the pieces, bricks and furniture.

 

5.     After low firing time is complete, turn switches to medium starting at the bottom and working up.  Lid is still open and top peep hole is still out.

 

6.     Fire on medium for 1 hour.  During firing, medium gasses are released from the pieces.

 

7.     After medium firing is done, turn all switches to high as before, close lid and plug peep hole.  During high the pieces will reach maturity.

 

8.     When the kiln shuts off automatically, two important things must be done, turn switches to off and turn timer off.

 

9.     Proper cooling of the kiln is important.  Lid must not be opened at anytime during firing or cooling.

 

10.  Allow kiln to cool for 24 hours.  Pieces should be cool enough to touch.  Pieces cooled too fast can crack.

 

11.  Unload kiln as carefully as you loaded.  Close lid and peep holes to keep clean.

 

These are general instructions but always check your jar of paint or glaze for the correct cone to fire to.  Also check the wall for signs.  Each kiln has slightly different instructions.