firing-001 - pişirme
1) Definition
source: Dave Finkelnberg
Heatwork: it is a combination of effects including:
- temperature
- duration of firing
- kiln atmosphere
- volume and mass within the kiln
- volatiles in the kiln
2) Measuring heatwork: pyrometric cones
We use pyrometric cones because, each cone within a temperature range has a separate behaviour, each of the cones has a has a separate chemical and physical composition.
Their composition is designed to permit the cone to bend over under the force of gravityat a particular temperature when heated at a specific rate.
There is an infinite combination of kiln heating rates and times.
So this bending does not begin at a specific temperature but rather at a combination of temperature and time. This means, cone cannot be considered a scientific measure of temperature, rather the cone shows off that a particular combination of time and temperature is reached
3) Pişirme teknikleri
3.1) to soak or not to soak (ısı sabitleme /bekletme)
source:Dave Finkelnberg
Some process in a firing are temperatur dependent, while others are time dependent.
A soak may be used at any point in a firing.
A soak reduce the difference between the surface and interna; temperature of ware in a kiln
3.2.) Temperature dependent process:
A soak at different temperature is critical and useful to the following process. TR: Belirli ısılar bu yukarıdaki prosesşer için kritik öneme sahip. Bu ısılara erişildiğinde ısıyı sabitlemek (soak) prosesin tam oluşmasına yararlı olacaktır:
- organic burn off
- driving off chemically bound water
- mullite formation
- silica melting
Once a glaze is melted, it will become less viscous (flow easily = katılaşacak) as temp increases.
The viscosity of a melten glaze is temperature dependent. A soak may be used to hold the viscosity of a melted glaze constant.
While time passes so that the glaze may flow or smooth out
This type of soak is often used to improve the final surface appearance of a glaze.
3.3) Atmosphere controlling kiln
source: Edward Orton Jr. / Ceramic foundation
Different degrees of oxidation (Tr: oksijen ile temas) and/or reduction may be used during the soakto further influence the appearance of the glaze surface.
3.4) Soak without over firing
- a particular cone is down (not the last?)
- temp is held constant for 15 minutes
- so we increased the firing by one cone
- the target cone is fully bent to a 90 angle - > end of soak
3.4) Slow cooling in electirc Kilns
Slowly colling is used for variety of purposes:
- slow cooling large work to reduce dunting
- cooling slowly and soaking (holding a temp) to form glaze cystals
- Slower cooling reduces stress on ceramic wares
- for glaze containing, these can result in some spectacular effects
- feathering to small crystals
- fully developed satin-matte surface
- and many more
- containing materials
- zinc, rutile, calcium
- magnesium, lithium, iron
- combination of short soak at peak temp and down firing may result in eliminate pinholing in glaze
Many more computer controlled kilns come with built in pre-heat or cool-down programs
Tip: for using pre-program set up kilns test the program in a typical firing using self supporting Orton cones to calibrate the kiln (cone 6 is over firing)
4.1) Bana öğretilen
Bisküvi
980 C ile 1020 C arası fırınlanmalı yoksa malzeme uyuşmazlığı ortaya çıkar
950 C de fırınlanırsa sır malzeme uyuşmazlığı ile tutmaz veya bozuk çıkar
1050 C de fırınlanırsa, sır tutmaz (beyaz kilde bunun tersini pek çok defa yaptığını bir seramikçi söyledi, ama doğru mu bilmiyorum)
4.2) Deneyim-14-09-2019
4.2.1) Kırmızı kil -
Aşağıdaki malzemede trapez şekiller daha ince idiler, daha fazla küçüldüler.
Hesaplamada trapez ve kare parçaların küçülmeleri ayrı değer ile yapılmalı
Islak kil boyutuları:
- a - 69mm - trapez
- b - 68 mm - trapez
- c- 110 mm x 111 mm - kare
- d - 107 mm x 110 mm - kare
Kuru kil boyutları:
- a - 61 mm - küçülme : % 11,59
- b - 60 - küçülme : % 11,76
- c - 100 mm x 100 mm - küçülme : % 9,9
- d - 98 mm x 99 mm - küçülme : % 8 - %10
İlk fırın boyutları - bisküvi
- a - 60 mm - küçülme : %
- b - 59,53 mm - küçülme : %
- c - 99,67 mm - küçülme : %
- d - 96,45 mm - küçülme : %
İkinci fırın - sırlama
- a - 1 mm - küçülme : %
- b - 1 mm - küçülme : %
- c - 1 mm - küçülme : %
- d - 1 mm - küçülme : %
4.2.2) Cam
Eski camların erimesi daha mükemmel
karo fayans seramikleri erimesini arttırmak için boraks kat (Kalaçlar'da var). Boraks daha düşük derecede camın erimesini sağlıyor.
4.2.3) Seramik Ar / Ge
note : Trains in India are serving tea in clay cups to fight plastic pollution
5) Bisque firing
Range
Fragile with high porosity firing: 998 C (1828 or cone 6)
6)Çini fırınlama
13 Mart 2023 Lerzan hoca ile 2. çini fırınlama
- Seramik üzeri şeffaf çini sır:
- çatlamaya sebep oluyor- efektli gibi.
- Sebebi farklı yüzey gerilmeleri
- Çini fırını 925 C da çalıştırıldı
- seramik şeffaf sır (seramik üzeri) iyi sonuç verdi
- Çinide
- Kırmızı ve siyah: 2 kat yetersiz oluyor. En az 3 kat olmalılar
- Çini sır karışımı
- 850 gr kurşunsuz sır
- 150 gr kurşunlu sır
- 10 gr selüloz
7) Raku
7.1) Obvara pişirim tekniği / Baltık Raku
Bisküvi yapılırken, seramik 900 C derecede fırından çıkarılır
un, su, şeker, ve mayadan oluşan organik karışım içine daldırılır,
ardından su ile temizlenir (soğunyunca mı? hangi derecede?)
Teknik orijini baltık bölgesidir
7.2) Saggar firing
source: potterywheel.com
7.2.1) Saggar - Definition
Container that is designed to keep a selection of materials close to the surface of the pot as it fires
7.2.2) Different ways
- Pots fired inside an oldtin can that contains a selection of materials close to the surface of the pot as it fires
- Wrapping paper clay around a pot
- Dip strips of paper in clay slip and make something like a paper mache coccon around the pot
7.2.3)What you need
- Plastic table or plastic sheet on table
- Rubber gloves
- Safety googles
- Plastic bowl
- Ferric Chloride solution
- Respirator filtering vapor
- Salt shaker
- Aluminum foil
- Old rays or paper towelling
- plastic garbage bag
7.2.4)Saggar firing materials that can be used
- Copper sulfate
- Iron sulfate
- Granulated sugar
- Miracle gro
- Horse hair
- String soaked in salt solution
- Sawdust
- Straw
- Seaweed
- Epsom salts
- Manganese sulfate
- Dried banana peel
- Steel wool
- Coffee grounds
- Corn husks
- Copper wire
7.2.5) Selection of pots
- Wheel turned or hand building
- The surface should be nice and smooth
- The pots should be bone dry
- Apply 3 layers of terra sigillata (parlak kirmizi astar)
- Buff it up to shine (parlatmak) using a soft lint-free(parça/tiftik) cloth
- Bisque fire to cone 6 - 1823F / 995C
- Put in a salt-shaker (must have big holes) together
- copper sulfate
- iron sulfate
- miracle gro
- Apply 3 layers ferric chloride (highly corrosive) to the outside surface of bisque fired pot
- let it dry before each coating
- On second coat apply the mix in salt shaker
- cover all up in two coat of aluminum foil
- Fire
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