Izisekelo ze-glaze

Iyini i-glaze

I-glaze wungqimba oluncane lwengilazi olunamathele embizeni ngokuncibilika. I-Glazy, umtapo ovulekile wamaresiphi e-glaze, iyibiza ngokuthi “ifomula yengilazi elungiselelwe ukuncibilika nokunamathela ebumbeni emazingeni athile okushisa”. Ifakwa njengongqimba lwempuphu, bese incibilika ku-kiln (isithando sokushisa izitsha zobumba) ibe wungqimba olufana nengilazi oluvala ubumba, ngakho imbiza ayinamathuba amaningi okuvuza, ukungcoliswa noma ukuguguleka. Ekushiseni okuphezulu kakhulu, okuncibilikile kuphinde kusebenzisane nobumba, kaningi kwakhe ungqimba phakathi kwazo olubamba i-glaze iqine. Ku-earthenware i-glaze ihlala phezulu njengongqimba oluhlukile; ku-stoneware incibilikela emzimbeni wobumba.

Iresiphi ibala okokwakha, njenge-feldspar, i-whiting ne-kaolin. Ku-kiln, ingxenye yento ngayinye iphuma njengegesi (amanzi noma i-carbon dioxide) bese okusele kuba ama-oxide: izinhlanganisela ze-element ne-oxygen, njenge-silica (SiO₂) noma i-calcium oxide (CaO). Ingilazi eshisiwe yenziwe ngama-oxide, ngakho ababumbi bachaza i-glaze ngawo. I-oxide ngayinye yenza umsebenzi owodwa kwemithathu.

• I-silica (SiO₂) iyakha ingilazi (glass former): yakha ingilazi. I-silica emsulwa incibilika ngaphezu kuka-1700 °C (3100 °F), kushisa kakhulu kune-kiln yokubumba, futhi i-glaze ene-silica eningi ngokuvamile ihlala isikhathi eside.
• Ama-flux (izincibilikisi) yehlisa izinga lokuncibilika abe yilelo i-kiln engalifinyelela. Ama-alkali, abhalwa R₂O, angama-oxide e-sodium, e-potassium ne-lithium (Na₂O, K₂O, Li₂O); asebenza kusukela ku-cone 06 kuya phezulu ekushiseni okuphakathi nokuphezulu. Ama-alkaline earth, abhalwa RO, angama-oxide e-calcium, e-magnesium, e-barium ne-strontium (CaO, MgO, BaO, SrO), ne-zinc oxide (ZnO) ifakwe eqenjini lawo; asebenza kangcono kusukela ku-cone 5 kuya ku-cone 10. U-R umele noma iyiphi insimbi yalowo mndeni.
• I-alumina (Al₂O₃) iyasimamisa (stabilizer). Yenza okuncibilikile kuqine ukuze kuhlale ezindongeni ezimile, futhi yengeza ubulukhuni nokuhlala isikhathi eside. Isexwayiso se-Glazy: uma i-alumina incane kakhulu “i-glaze yakho ingageleza; uma iningi kakhulu ingaqinisa okuncibilikile kube yi-matte”. I-alumina ivela kakhulu ebumbeni nase-feldspar.

I-boron (B₂O₃) ifiphaza umugqa. Osokhemisi bayibala njengento eyakha ingilazi, kodwa emazingeni okushisa e-studio isebenza njenge-flux, futhi ababumbi bayiphatha kanjalo. Ibaluleke kakhulu ku-cone 5–6 futhi ayidingeki ekushiseni okuphezulu. (Ama-cone, indlela ababumbi abaqamba ngayo ukushisa, achazwe ngezansi.)

Indlela eyodwa yokukukhumbula: i-silica yingilazi, ama-flux ayivumela ukuthi incibilike ezingeni lokushisa i-kiln yakho engalifinyelela, futhi i-alumina iyijiyisa ukuze ihlale lapho uyibeke khona.

Ubumba, izembozo nokushisa okubili

Izinhlobo zobumba

Umzimba wobumba (clay body) wubumba imbiza eyenziwe ngalo. Kunezinhlobo ezintathu ezinkulu.

• I-earthenware: umzimba wokushisa okuphansi, cishe i-cone 06–02, ohlala unezimbobo ezincane. Kaningi ubomvu noma umbala we-buff, futhi udinga i-glaze ukuze ubambe amanzi.
• I-stoneware: umzimba wokushisa okuphakathi kuya kokuphezulu, cishe i-cone 5–10, oba yi-vitreous noma ucishe ube yiyo.
• I-porcelain: umzimba omhlophe wokushisa okuphezulu ocebile nge-kaolin, kaningi okhanyisa ukukhanya.

I-vitreous isho okufana nengilazi nokungenazo izimbobo ezincane; i-vitrification wumzimba uba njalo njengoba ushiswa. Ababumbi base-UK kaningi badweba umugqa ngezinga lokushisa esikhundleni salokho: i-stoneware ishiswa ngaphezu kuka-1200 °C (2192 °F), i-earthenware ngaphansi kwalo. Ukushisa okuphakathi, i-cone 5–6, kuwela eduze ezinhlangothini zombili zalowo mugqa.

Izembozo nokomisa

I-slip wubumba oluxutshwe emanzini, olokuthela esikhunjeni, ukuhlanganisa noma ukuhlobisa. I-engobe yisembozo esifana ne-slip, kaningi esinombala, esinezinto eziningi ezingebona ubumba. I-underglaze yi-slip enombala noma umhlobiso we-oxide, ngokuvamile ombozwa nge-glaze ecacile.

Izitsha ezingashisiwe zingama-greenware (imithombo ayivumelani ngokuthi leli gama lihlanganisa zonke izitsha ezingashisiwe noma ezomile kuphela). Njengoba zoma ziba leather-hard (lukhuni njengesikhumba), ziqinile kodwa zisamanzi kancane, isigaba sokuzicwecwa nokufaka izibambo; bese ziba bone dry (zomile nya), zingenawo amanzi akhululekile asele, zibuthaka kakhulu futhi zilungele ukushiswa.

Ukushisa okubili

Ukushisa kokuqala, okuphansi, yi-bisque (UK: biscuit), ngokuvamile i-cone 08–04 (kaningi kakhulu 06–04), cishe 942–1063 °C (1728–1945 °F). Kushiya izitsha ziqinile kodwa zinezimbobo ezincane. I-Digitalfire, iwebhusayithi yolwazi nge-glaze, iphakamisa ngokuvamile izimbobo ezingaphezu kuka-15%, ukuze i-bisque idonse amanzi ku-glaze njengoba ifakwa. I-bisque ethambile (i-cone 08–06) inezimbobo eziningi; i-bisque eqinile (kaningi i-cone 04) inamandla kodwa yamukela i-glaze kancane.

I-Potclays, umhlinzeki wase-UK, ichaza ukushisa kwe-biscuit kuze kube cishe ku-1000 °C (1832 °F), cishe i-cone 06. Uma sifunda le mithombo ndawonye, siphakamisa i-cone 06–04 ye-bisque yokuqala: 998–1063 °C (1828–1945 °F) ngesivinini esiphakathi se-Orton.

Ukushisa kwe-glaze (ababumbi baseBrithani bangathi ukushisa kwe-glost) kuncibilikisa i-glaze futhi, ku-stoneware, kuvuthisa nobumba. Ukushisa kanye (once-firing) kufaka i-glaze ezitsheni ezingashisiwe bese kuzishisa kanye kuphela. I-Digitalfire ibika isimo sokukhiqiza lapho izitsha ezifakwe i-glaze zingashisiwe zahoxa emaphethelweni azo kwaze kwaba ukushisa kwe-bisque kwakulungisa, ngakho qala ngokushisa okubili. Ukushisa ku-kiln elula kunikeza amashejuli akho kokubili.

Ama-cone ne-heatwork

Ababumbi baqamba ukushisa nge-cone: iphiramidi encane yobumba olushisiwe egoba uma isithole inani elithile lokushisa. I-Orton, ewenzayo, ikubeka kanje: “Ama-cone awalinganisi izinga lokushisa lodwa. Alinganisa i-heatwork, umphumela ohlangene wesikhathi nezinga lokushisa.”

I-heatwork yisizathu: i-glaze, ubumba ne-cone konke kusabela esikhathini okushisa ngaso kanye nokuthi kushisa kangakanani. Ukushisa okuhamba kancane kugoba i-cone ezingeni lokushisa eliphansi, okusheshayo ezingeni eliphezulu. Ishadi le-Orton libonisa i-cone 6 igoba ku-1185 °C (2165 °F) uma ukushisa kuphela kukhuphuka ngo-15 °C (27 °F) ngehora, ku-1222 °C (2232 °F) ngo-60 °C (108 °F) ngehora, naku-1243 °C (2269 °F) ngo-150 °C (270 °F) ngehora, isivinini silinganiswa ku-100 °C (180 °F) yokugcina. I-cone isiqedile uma isihloko sayo sesigobe ngo-90°, i-Orton ekubiza ngokuthi yindawo yehora lesi-5.

Izinombolo zama-cone zisuka ku-022 kuya ku-42. U-zero ongaphambili ukhombisa uchungechunge olupholile, lapho inombolo enkulu ipholile khona: i-cone 06 ipholile kune-cone 04, ne-cone 01 ipholile kune-cone 1.

Qamba futhi uhlele ukushisa kwakho nge-cone, futhi uthathe amazinga okushisa njengokulinganiselwa. I-witness cone eshalofini phakathi kwezimbiza, noma i-cone pack yama-cone amathathu (i-guide, i-firing ne-guard cone), ibonisa i-heatwork izimbiza zakho ezayithola ngempela.

Amazinga okushisa ashicilelwe ayahlukahluka. I-Glazy inikeza ukushisa okuphezulu, i-cone 9–11, njengokucishe kube ngu-1280–1310 °C (2336–2390 °F), okufana nekholamu esheshayo ye-Orton, futhi i-Digitalfire ibika ukuthi ama-kiln amaningi afinyelela i-cone 6 cishe ku-1204 °C (2200 °F). Iseluleko sethu: sebenzisa izinombolo ze-Orton zesivinini esiphakathi, njengoba lo mhlahlandlela wenza, hlela nge-cone, bese uyekela i-witness cone inqume.

Ngaphandle kweNyakatho Melika, abahlinzeki kaningi banikeza u-°C esikhundleni se-cone. U-Hermann Seger wathuthukisa i-cone yanamuhla, eyaqala ukusetshenziswa eBerlin ngo-1886, futhi i-UK ibinama-cone ayo e-Staffordshire; izinombolo zawo akufanele zicatshangwe ukuthi zifana nezama-Orton, futhi asitholanga thebula lokuziguqula. Ukushisa ku-kiln elula kuchaza ama-cone ngokuningiliziwe.

Kusuka eresiphini kuya ku-unity formula

Iresiphi ye-batch (batch recipe) ibala okokwakha ngesisindo, ngokuvamile kulinganiswe ukuze isisekelo sihlangane sibe ngu-100. Okokwengeza (additives: okokufaka umbala, ama-opacifier nokokumisa) kwengezwa ngaphezu kuka-100, ngokuvamile njengephesenti lesisekelo. Ukuze babone ukuthi i-glaze iyini, ababumbi baguqula iresiphi ibe yi-unity molecular formula (i-UMF, noma i-Seger formula, ngokuka-Hermann Seger, owaqala ukusebenzisa isakhiwo sayo samakholamu amathathu).

Ikhasi leresiphi le-Glazecalc lenza zonke izinyathelo ezine njengoba uthayipha, futhi libonisa umphumela ngamakholamu amathathu: ama-flux (R₂O ne-RO) ahlangana abe ngu-1; okusimamisayo (R₂O₃: i-alumina, ne-boron kaningi ifakwa lapha); nokwakha ingilazi (RO₂: i-silica). “I-unification iyithuluzi lokulinganisa nje,” kusho i-Glazy: amaresiphi amabili enziwe ngezinto ezahlukene kodwa ane-unity formula efanayo “aziphatha cishe ngendlela efanayo uma eseshisiwe”. Ngakho u-1 uyisilinganiso esabelwanayo, hhayi inani olikalayo. I-Digitalfire yengeza ukuthi le ndlela “ayisebenzi kahle kangako emazingeni okushisa aphansi”, lapho i-boron ingeyona i-flux elula, nokuthi ama-unity formula “angawokuqhathanisa futhi abonwa kangcono esimweni sawo”. Qhathanisa ibeka ama-formula amaresiphi amabili eceleni kwelinye, i-oxide ngayinye.

Isilinganiso se-silica ne-alumina

Inombolo eyodwa ewusizo kakhulu yisilinganiso se-silica ne-alumina (silica to alumina ratio): i-silica ihlukaniswe nge-alumina. Esibonelweni, u-3.70 ÷ 0.41 ucishe ube ngu-9.

Isilinganiso esingu-5–7 asibikezeli ukucwebezela noma i-matte sisodwa: ama-flux, i-boron ne-cone konke kusunduza umugqa. I-Glazy inikeza ukulingana kwama-flux okuvamile kuma-glaze azinzile okungu-0.2 R₂O no-0.8 RO, kuze kube ngu-0.3 R₂O no-0.7 RO. I-alkali eningi yenza okuncibilikile kugeleze kakhulu futhi yenyuse ukukhula kwakho, ngakho nengozi ye-crazing.

I-loss on ignition

I-loss on ignition (i-LOI) yisisindo into esilahlekelwa ku-kiln njengoba amanzi, i-carbon dioxide, izinto eziphilayo noma i-sulfur kuphuma njengegesi. I-glaze eshisiwe ayinayo, ngakho i-unity formula iyayishiya.

Igesi ephuma ngemva kokuba i-glaze iqale ukuncibilika kumele ibhamuze idlule kuyo, idale, ngamazwi e-Digitalfire, “amagwebu, amabhamuza, izimbobo ezincane, ukuhoxa”. I-talc iqhubeka ikhipha igesi kuze kube cishe ku-899 °C (1650 °F). Ama-frit, izinto ezi-calcined (ezishiswe ngaphambili ukuze kuxoshwe amagesi azo) nezinguquko ekushiseni konke kuyasiza.

Izincwadi ezindala zenza lezi zibalo ngesandla, nge-molecular weight (isisindo se-mole eyodwa yento noma ye-oxide) ne-equivalent weight (isisindo sento esinikeza i-mole eyodwa ye-oxide). Ngezibalo zethu, cishe u-100 g we-whiting unikeza i-mole eyodwa, u-56 g, we-calcium oxide. Ikhalkhuleytha iphatha kokubili.

Ama-frit nokokwakha okuluhlaza

Ama-frit

I-frit yingilazi eyenziwe efektri: amaminerali ancibilikisiwe, apholiswe ngokushesha emanzini futhi agaywe. Ukwenza i-frit kwenza izinto ezincibilika emanzini njenge-borax zingancibiliki, kubopha ama-oxide anoshevu njengomthofu (lead, Pb) ne-barium engilazini ezinzile, kunikeza into engaguquki kunamaminerali aluhlaza, futhi kuxosha amagesi, ngakho ama-glaze ane-frit “awanawo amaphutha amaningi kakhulu” (Digitalfire). Ama-frit futhi ancibilika ngokushesha: i-soda frit iyasebenza ku-cone 06, kanti i-feldspar “isaqala nje ukuthamba ku-cone 6”. Abiza kakhulu, adinga ubumba ukuze ahlale exubile emanzini (isibonelo se-Digitalfire ngu-85% we-frit no-15% wobumba), futhi “ngokwethiyori awancibiliki emanzini, kodwa empeleni ayancibilika”.

Ama-frit aseNyakatho Melika aqanjwa ngomenzi nangenombolo: i-Ferro Frit 3134 (i-Ferro manje isiyi-Vibrantz) ikumaresiphi omphakathi e-Glazy acishe abe ngu-22%. Amaresiphi ase-UK kaningi aqamba ama-frit ajwayelekile, njenge-standard borax frit.

Okokwakha okuvamile

Amagama ezifunda

• I-kaolin yi-china clay e-UK; abahlinzeki base-Australia bayidayisa njenge-Eckalite.
• I-flint yigama elidala lase-UK le-silica. Abahlinzeki base-UK basadayisa i-calcined flint njengomkhiqizo wayo, ngakho i-“flint” eresiphini yaseBrithani cishe isho i-calcined flint, kanti kweyaseMelika cishe isho i-quartz egayiwe. Kokubili kudayiswa njengemithombo ye-silica; hlola ukuhlaziywa.
• I-china stone ne-Cornish stone (Cornwall stone) yinto efanayo, ehlobene ne-feldspar.
• I-whiting yi-calcium carbonate; abahlinzeki baseJalimane bayibiza ngokuthi yi-Kreide (chalk).

Yahlulela into ngama-oxide eyinikezayo, hhayi ngegama layo. I-Glazecalc isebenza ngaleyo ndlela: ungafaka ukuhlaziywa komhlinzeki wakho ku-khasi lokokwakha, futhi Zama okokwakha kwanamuhla bese uqhathanisa, Phakamisa amanani bese uqhathanisa kanye nokuthi Fanisa nalokho enginakho konke kufanisa ama-oxide ashisiwe, hhayi amagama.

Okokwakha nakho kuyashintsha. I-Custer feldspar yaphela ngo-2023. Imayini yokuqala ye-Gerstley Borate yavalwa cishe ngo-1999–2000; i-Laguna isadayisa umkhiqizo ngaleli gama, futhi i-Gillespie Borate yindawo yayo enkulu. Imithombo ayivumelani ngokuthi i-Gillespie ingena esikhundleni se-Gerstley Borate ngesisindo esifanayo (umenzi wayo ne-Potclays bathi yebo, i-Digitalfire nabanye bathi cha), ngakho qhathanisa lezi zombili ku-Glazecalc, bese uhlola i-batch encane.

Okokufaka umbala nama-opacifier

Okokufaka umbala (colorant) yi-oxide yensimbi noma i-carbonate enikeza i-glaze umbala; i-stain yisifaki-mbala esenziwe efektri, esizinzile futhi esingaguquki kunama-oxide aluhlaza. Okokufaka umbala ngokuvamile kungaphansi kuka-5% wesisekelo, okuningi kungaphansi kuka-1%, futhi i-carbonate inamandla acishe abe yingxenye yawe-oxide ehambisana nayo.

Amanani e-cobalt ne-chrome ayaphikiswana ngempela. I-Glazy ithi u-0.1% we-cobalt wanele ukunikeza okuluhlaza okwesibhakabhaka; i-Glendale Community College inikeza u-½–2% noma u-½–3% kuye ngomoya ongaphakathi; u-Birdie Boone, ku-Pottery Making Illustrated, uthi u-3% noma ngaphansi. Nge-chrome, u-Boone uthi ngaphansi kuka-0.5% kanti i-Glendale ithi u-2–3%. Indlela ephephile wukuqala ngokuncane bese wenza i-line blend: umugqa wama-test tile ashintsha into eyodwa kusukela kokuncane kuya kokuningi.

I-glaze eyisisekelo iyawushintsha umbala. Isisekelo esicwebezelayo, esibonisa ngaphakathi sinikeza umbala okhanya kakhulu; izisekelo ze-satin ne-matte, ngokuvamile ezine-alumina eningi, ziwufiphaza. I-magnesium isunduza i-cobalt iye ku-purple, i-zinc yenza i-chrome ibe nsundu, futhi i-chrome ne-tin kunikeza okubomvana.

Ama-opacifier

I-opacifier yenza i-glaze ingabonisi ngaphakathi (opaque), ifihle ubumba; i-glaze ebonisa ngaphakathi (transparent) iyabuyekela ubonakale.

Ukulingana kwe-glaze namaphutha

Ubumba ne-glaze kokubili kuyakhula uma kushisa futhi kuyancipha uma kuphola, ngakunye ngenani lakho: ukukhula ngokushisa kwakho (thermal expansion). Ukulingana kwe-glaze (glaze fit) yindlela lezi zombili ezifana ngayo. Ukulingana okuhle kushiya i-glaze icindezelwe kancane wubumba; i-Digitalfire ithi ukucindezelwa okuncane kuqinisa izitsha, kanti ukucindezelwa okukhulu kakhulu kungazenza buthaka futhi kuziqhekeze.

I-crazing ne-shivering

I-crazing (imifantu emincane) wuxhaxha lwemifantu emincane. Ukukhula kwe-glaze kuphakeme kunokomzimba, ngakho uma kuphola iyancipha kakhulu, idonswe futhi iqhekeke, ngokuvamile ngenxa ye-sodium ne-potassium eningi kakhulu (Na₂O, K₂O). Ingavela futhi kamuva, isetshenziswa, ngemva kokupholiswa ngokushesha kaningi njengokuthinta uketshezi olubandayo. Uma ifunwa, njengaku-raku, ibizwa ngokuthi i-crackle. I-Digitalfire ithi “ezikhathini ezingu-95% isixazululo wukulungisa ukukhula ngokushisa kwe-glaze”; ukupholisa kancane kubambezela nje i-crazing. Ukuhlola kwayo: shisa izitsha zibe cishe ngu-149 °C (300 °F), uzicwilise emanzini anamakhaza eqhwa, bese uhuqa ngepeni le-felt phezu kwazo ukuze kubonakale imifantu.

Imithombo ayivumelani ngokulungisa kokuqala. I-Glazy iphakamisa ukwengeza i-silica noma i-alumina; i-Digitalfire iphendula ngokuthi i-silica eyengeziwe “ihlambulula nje i-KNaO” (i-sodium ne-potassium); u-Linda Bloomfield wengeza i-boron noma anciphise i-feldspar, into eyodwa ngesikhathi. Iseluleko sethu: kukhalkhuleytha yeresiphi, shintsha enye i-sodium ne-potassium ngama-flux okukhula okuphansi (i-boron, i-lithium, i-magnesium, i-calcium), hlola ushintsho nge-Qhathanisa, bese uqinisekisa ngokuhlola kwamanzi eqhwa.

I-shivering yisiphambano: ukukhula kwe-glaze kuphansi kakhulu kunokomzimba, ngakho icindezelwe ngokweqile futhi iyaxebuka emaphethelweni nasemaceleni. I-Digitalfire iyaxwayisa ukuthi amaxebuka angabukhali njengensingo futhi angagwinywa, futhi i-Glazy ithi i-shivering “iyingozi kakhulu kune-crazing ezitsheni ezisetshenziswayo”. Ukulungisa yi-glaze yokukhula okuphezulu noma umzimba wokukhula okuphansi.

Ukucwebezela ne-matte

Ubuso obucwebezelayo (gloss) buyakhanya futhi bushelelezi, i-satin inokukhanya okuthulile, kanti i-matte ayicwebezeli. Ukucwebezela kudinga ingilazi encibilike ngokuphelele. I-matte ingavela ku-alumina eningi (isilinganiso se-silica ne-alumina esiphansi), kuma-flux afana ne-calcium, i-magnesium, i-barium noma i-strontium akha amakristalu amancane njengoba i-glaze iphola, noma ekungashisweni ngokwanele.

Amaphutha avamile

Shintsha into eyodwa ngesikhathi, futhi ugcine ama-test tile akho.

Ukuphepha kokudla

Ukuvuza kwezinsimbi (leaching) yinsimbi encibilika iphuma ku-glaze eshisiwe ingene ekudleni noma esiphuzweni, futhi i-glaze ingabukeka iphelele kodwa ikwenze lokho. Ukuhlolwa okusemthethweni kucwilisa ucezu olushisiwe ku-solution ene-asidi bese kulinganisa umthofu (lead, Pb) ne-cadmium okuphumayo.

Ukungabi namthofu akufani nokuphepha ekudleni

Imithetho yase-US, ye-EU, ye-UK neyase-Australia ibeka umkhawulo womthofu (Pb) ne-cadmium ucezu olushisiwe olukukhiphayo, hhayi lokho i-glaze enakho. “Engenamthofu (lead-free)” isusa ingozi eyodwa; ayisona isilinganiso sokuphepha ekudleni. Amanye ama-oxide nawo ayavuza: i-Glazy iyaxwayisa ukuthi ama-glaze ane-barium eningi “angavuza futhi ngokuvamile awaphephile ekudleni”, i-Digitalfire ithi i-copper “ingenza i-glaze ivuze; yihlole”, futhi i-Glazy ayisaluleki ama-glaze anomthofu (Pb) ezitsheni ezisetshenziswayo.

I-liner glaze yi-glaze ezinzile, ngokuvamile ecacile noma emhlophe, yezindawo ezithinta ukudla. Ngombono wethu, engenakho okokufaka umbala, i-barium, umthofu (Pb) noma i-lithium, encibilika ngokuphelele, engenayo i-crazing futhi ehlala kahle, iwukukhetha okunengozi encane. Ingozi encane akusona isiqinisekiso.

Ama-limit formula (i-Digitalfire ikhetha ama-target formula) anikeza amabanga avamile e-unity formula kuma-glaze azinzile ku-cone: ama-target e-cone 6 e-Digitalfire abeka i-alumina ku-0.285–0.64 ne-silica ku-2.4–4.7. Akuqondisa kukhemistri enhle kodwa akufakazeli lutho; i-Digitalfire igwema igama elithi “limit” ngoba liphakamisa ukuthi ama-glaze angaphakathi kwamabanga “aphephile ngandlela thile”. Amathuluzi e-Glazecalc okushintsha iresiphi asho uma entsha yeqa umkhawulo onconywayo, njenge-boron eningi ku-cone 6, nokuthi i-glaze cishe izokwenzenjani.

Imikhawulo esemthethweni iyahlukahluka ngezwe. Ithebula libonisa leyo yalapho uhlala khona, ngamayunithi omthetho uqobo; khetha elinye izwe noma isifunda ukuze uqhathanise.

E-US, izitsha zobumba zokuhlobisa ezibukeka zingasetshenziselwa ukudla ziphathwa njengezitsha zokudla ngaphandle uma zinelebula enamathiselwayo nesaziso esihlala njalo esibunjwe noma esishiswe phansi kwazo, njengokuthi “Not for Food Use. May Poison Food”, noma zinembobo edlula endaweni yokudla. I-EU ibeka imikhawulo yomthofu (Pb) ne-cadmium ku-Directive 84/500/EEC, futhi i-UK igcina izinombolo ezifanayo emthethweni wayo. Kusukela mhla zingu-29 May 2026 i-Netherlands, i-Belgium ne-Luxembourg zivumela umthofu (Pb) ophansi cishe izikhathi ezingu-130 kuya ku-150, ne-cadmium ephansi cishe izikhathi ezingu-15. I-Australia ibeka imikhawulo yezitsha ezingeniswa ezweni; asitholanga mkhawulo osemthethweni wezitsha ezenziwe e-Australia noma e-New Zealand.

Ukuhlola

I-FDA ithi amakhithi okusula asekhaya angabonisa umthofu (Pb) ongavuza, kodwa i-Ceramics New Zealand iyaxwayisa ukuthi amapeni okuhlola akenzelwanga izitsha zobumba futhi anikeza imiphumela emihle engamanga. Thatha umphumela omuhle njengesizathu sokuyeka ukusebenzisa ucezu, nomphumela omubi njengongafakazeli lutho. Ukuhlolwa kokuvuza kwezinsimbi (leach test) kocezu olushisiwe elabhorethri (i-ASTM C738 e-US; i-EN 1388 noma i-ISO 6486 e-Europe) kuyimpendulo yangempela.

I-specific gravity nokufaka

I-specific gravity

Impuphu ye-glaze exutshwe namanzi yi-slurry. I-specific gravity yayo (i-SG) yisisindo sayo uma siqhathaniswa nevolumu efanayo yamanzi, ane-SG engu-1.0: uma iphakeme, impuphu iningi ebhakedeni. Izincwadi ezindala zase-UK zithi pint weight. I-Glazy ithi u-1.4–1.5 “uyindawo enhle yokuqala kuma-glaze amaningi”. Ukuyilinganisa, kala ngqo u-100 mL we-slurry (i-Glazy iphakamisa isirinji) bese uhlukanisa ngo-100: u-145 g usho i-SG 1.45. Ama-hydrometer awathembeki kuma-glaze ajiyile, futhi amanzi ayahwamuka, ngakho hlola futhi ngaphambi kokufaka i-glaze.

Ama-target ahlukahluka ngomthombo. I-Digitalfire ibeka ama-glaze okucwilisa ku-1.40–1.50 nama-glaze okuthengwa okubhulashwa ku-1.25–1.55, kanti i-Potclays inikeza u-1.71–1.81 wokubhulasha no-1.71 wokufafaza. Iseluleko sethu: cwilisa cishe ku-1.45 i-glaze ijiyile kancane, landela ilebula ye-glaze yokubhulasha, bese ubhala phansi okusebenzayo.

I-flocculant (i-Epsom salts, uviniga noma i-calcium chloride) ijiyisa i-slurry kancane, iyenze ibe thixotropic: iyageleza uma igovuzwa futhi iyajiya uma ithule, ukuze “i-glaze imboze ngokulinganayo, ingaconsi”. I-deflocculant (i-sodium silicate noma i-Darvan) iyayihlambulula. Indlela yokwenza i-glaze ichaza ukuxuba nokulungisa.

Ukufaka i-glaze

Qala ngokuhlanza uthuli namafutha ku-bisque ngesipontshi esimanzi kancane nje esikhundleni sokuyigeza, okuyimunca amanzi. Ungalushayi uthuli ngomoya ocindezelwe noma ulubhulashe lomile: lokho kufaka uthuli lwe-silica emoyeni (Ukuxuba ngokuphepha nomoya ohlanzekile).

• Ukucwilisa “ngokuvamile kunikeza ungqimba olunogqinsi olulinganayo” (Robin Hopper). Isikhathi sokucwilisa sinquma ugqinsi: i-Digitalfire iphawula ukuthi ama-glaze okuthengwa okucwilisa enziwa cishe ku-1.4 ukuze acwiliswe imizuzwana engu-5 naku-1.5 ukuze acwiliswe umzuzwana o-1.
• I-glaze yokuthela kufanele ibe “mncane kancane kunalapho isetshenziselwa ukucwilisa”; lapho ukuthela kugqagqana khona, ungqimba luphindeka kabili futhi lungageleza.
• Ama-glaze okubhulasha aqukethe i-gum efana ne-CMC gum, esiza i-glaze igeleze futhi inamathele, bese iyasha. Amaningi adinga izingqimba eziningana, kaningi ezimbili noma ezintathu; landela ilebula.
• Ukufafaza kusebenzisa i-glaze encane kakhulu, efakwa “ngezingqimba eziningana ezincane, kancane kancane kwakhiwe ugqinsi”.

Ungqimba olugqinsi kakhulu lungahoxa, lube namabhamuza noma lugeleze. Imithetho yabahlinzeki isuka ogqinsini lwekhadi lesikweletu kuya kolwe-dime yase-US, ngokulinganisa kwethu cishe u-1 mm we-glaze eyomile; ama-test tile anogqinsi oluhlukahlukene kuyindlela ethembekile yokuhlola. I-wax resist onyaweni ixosha i-glaze, ukuze imbiza inganamatheli eshalofini, kanti i-kiln wash, isembozo esimelana nokushisa esivame ukwenziwa nge-kaolin ne-silica, ivikela amashalofu emaconsini.

I-oxidation ne-reduction

Amagesi angaphakathi ku-kiln, umoya wayo (atmosphere), ashintsha ukuthi ama-glaze aphuma kanjani. I-oxidation isho i-oxygen eningi. “Ama-kiln kagesi afana ncamashi nokushisa kwe-oxidation,” kusho i-Digitalfire, futhi ama-glaze e-oxidation ngokuvamile akhanya kakhulu kunawe-reduction, ikakhulukazi emazingeni okushisa aphansi. Ku-oxidation, i-copper inikeza okuluhlaza ne-turquoise, kanti i-iron okunsundu, okunsundu ngokukhanyayo nokubomvu. I-kiln kagesi engaphumi kahle umoya egcwele izitsha ezikhipha amagesi ingaba phakathi nendawo kunalokho okuhlosiwe; ipayipi lomoya elixhunywe ngqo ku-kiln liyasiza.

I-reduction inciphisa i-oxygen ngamabomu, ngokuvamile ku-kiln yegesi, yezinkuni noma ekhethekile. I-copper iba bomvu, kanti i-iron iba yi-flux enamandla kakhulu futhi inikeza i-celadon (okuluhlaza okwesibhakabhaka kuya kokuluhlaza okumpunga, kusukela ku-iron ecishe ibe ngu-½–2%) ne-tenmoku (temmoku: okunsundu okumnyama, i-iron ecishe ibe ngu-5–6%). I-Glazy ithi ama-celadon nama-copper red “ancike ku-reduction”. Nobumba buyashintsha: kokunye ukuqhathanisa kwe-Digitalfire, umzimba we-stoneware washa waba mpunga ku-reduction futhi waba phuzi kancane ku-oxidation. I-silicon carbide ku-glaze ingenza izindawo ezincane ze-reduction ngisho naku-kiln kagesi. Nge-reduction kusukela ku-cone 010 kuya ku-cone 3, i-Orton incoma ama-cone ayo angenayo i-iron.

Lindela ukuthi iresiphi ebhalelwe i-kiln yegesi ye-reduction iphume ngokuhlukile ku-kiln kagesi: i-celadon noma i-copper red encike ku-reduction ngeke ibukeke ngendlela efanayo ku-oxidation. Hlola ukuthi iresiphi yenzelwe muphi umoya, bese ubhala owakho, ne-cone, kumanothi eresiphi ku-Glazecalc.

Yonke i-kiln, nezikagesi, ikhipha intuthu namagesi (fumes), ngakho yikhiphele umoya ngaphandle. Ukuxuba ngokuphepha nomoya ohlanzekile kuchaza ukuthi kanjani.

Uhlu lwamagama

Okokwengeza (additive)

Okokufaka umbala, i-opacifier noma okokumisa okwengezwa ngaphezu kuka-100 weresiphi.

I-alumina (Al₂O₃)

Okusimamisayo okukhulu: kuvimba ukugeleza futhi kwengeza ubulukhuni. Kuvela ebumbeni nase-feldspar.

I-ball clay

Ubumba oluthambile olunensimbi (iron) eningi nezinto eziphilayo kune-kaolin.

Iresiphi ye-batch (batch recipe)

Okokwakha kwe-glaze ngesisindo, ngokuvamile kuhlangana kube ngu-100.

I-bentonite

Ubumba oluyimpuphu kakhulu olwengezwa ngo-1–3% ukuvimba i-glaze ukuthi izike.

I-bisque (UK: biscuit)

Ukushisa kokuqala, okuphansi, ngokuvamile i-cone 08–04 (kaningi kakhulu 06–04), okushiya izitsha ziqinile kodwa zinezimbobo ezincane.

I-boron (B₂O₃)

Ngokusemthethweni iyakha ingilazi kodwa isetshenziswa njenge-flux; ibalulekile kusukela ku-cone 06 kuya ku-cone 6.

I-CMC gum

I-gum ye-cellulose esiza i-glaze ibhulashwe futhi inamathele; iyasha.

Okokufaka umbala ne-stain (colorant and stain)

I-oxide yensimbi noma i-carbonate enikeza i-glaze umbala; i-stain yisifaki-mbala esenziwe efektri, esizinzile.

I-cone

Iphiramidi yobumba olushisiwe elinganisiwe egoba ku-heatwork ethile. I-witness cone ibonisa lokho izimbiza ezakuthola.

Ukuhoxa (crawling)

I-glaze ihoxa ibe ngamaconsi lapho ishiswa, ishiye ubumba bungembozwe.

I-crazing

Imifantu emincane ku-glaze encipha kakhulu kunomzimba wayo; i-crackle uma ifunwa.

I-devitrification

Amakristalu akhula engilazini ekuqaleni kokuphola, lapho engafunwa khona.

I-dunting

Imifantu embizeni ngenxa yengcindezi yokupholisa noma yokushisa, kaningi ku-quartz inversion, 573 °C (1063 °F).

I-earthenware

Umzimba wokushisa okuphansi (cishe i-cone 06–02) ohlala unezimbobo ezincane.

I-feldspar

Iminerali enikeza i-flux ye-alkali ne-alumina ne-silica: i-potash, i-soda noma i-nepheline syenite.

I-flocculant ne-deflocculant

Okokwengeza okujiyisa i-slurry (i-Epsom salts, uviniga) noma okuyihlambululayo (i-sodium silicate, i-Darvan).

I-flux

I-oxide eyehlisa izinga lokushisa lokuncibilika kwe-silica.

Iphephile ekudleni (food safe)

Emthethweni, ukukhipha umthofu (Pb) ne-cadmium okungaphansi kwemikhawulo ekuhlolweni nge-asidi. Akufani nokungabi namthofu.

I-frit

Ingilazi eyenziwe efektri, encibilikisiwe, epholiswe ngokushesha futhi egayiwe, eyenza ama-oxide ancibilika emanzini noma anoshevu angancibiliki.

Okwakha ingilazi (glass former)

I-oxide eyakha ingilazi, ngokuvamile i-silica.

I-glaze

Ungqimba lwengilazi oluncibilika lapho kushiswa ukuze luvale futhi luhlobise imbiza.

Ukushisa kwe-glaze (glaze firing; UK: glost firing)

Ukushisa okuncibilikisa i-glaze.

Ukulingana kwe-glaze (glaze fit)

Indlela ukukhula kwe-glaze nokomzimba okufana ngayo; ukulingana okuhle kushiya i-glaze icindezelwe kancane.

Okucwebezelayo, i-satin ne-matte (gloss, satin and matte)

Kuyakhanya futhi kushelelezi; ukukhanya okuthulile; akucwebezeli.

I-greenware

Izitsha ezingashisiwe: i-leather-hard uma ziqinile kodwa zimanzi, i-bone dry uma kungasekho amanzi akhululekile.

I-heatwork

Umphumela ohlangene wezinga lokushisa nesikhathi ku-kiln; lokho ama-cone akulinganisayo.

I-kaolin (UK: china clay)

Ubumba olumhlophe olumsulwa olunikeza i-alumina ne-silica; igcina i-glaze ixubile emanzini. E-Australia: Eckalite.

I-kiln wash

Isembozo esimelana nokushisa esivikela amashalofu e-kiln emaconsini.

Ukuvuza kwezinsimbi (leaching)

Izinsimbi ezincibilika ziphuma ku-glaze eshisiwe zingene ekudleni noma esiphuzweni.

I-limit formula (target formula)

Amabanga avamile e-unity formula kuma-glaze azinzile ku-cone; umhlahlandlela, hhayi isiqinisekiso.

I-line blend

Ukuhlola okushintsha into eyodwa phakathi kwamanani amabili. I-triaxial blend ishintsha ezintathu kugridi.

I-liner glaze

I-glaze ezinzile, ngokuvamile ecacile noma emhlophe, yezindawo ezithinta ukudla.

I-LOI (loss on ignition)

Isisindo esilahleka lapho kushiswa njengamanzi, i-carbon dioxide, izinto eziphilayo noma i-sulfur.

Ukushisa kanye (once-firing, single firing)

Ukufaka i-glaze ezitsheni ezingashisiwe nokuzishisa kanye kuphela.

I-opacifier

Into, njenge-zircon, i-tin oxide noma i-titanium dioxide, eyenza i-glaze ingabonisi ngaphakathi.

I-oxidation ne-reduction

Ukushisa nge-oxygen eningi (ama-kiln kagesi), noma nge-oxygen encishisiwe (ngokuvamile igesi noma izinkuni).

I-oxide

Inhlanganisela ye-element ne-oxygen; ukuhlaziywa kwama-oxide kuwabala ngephesenti lesisindo.

Izimbobo ezincane namabhamuza (pinholing and blistering)

Izimbobo ezincane, noma imigodi enemiphetho ebukhali, lapho igesi iphunyuke khona kokuncibilikile.

I-porcelain

Umzimba omhlophe, ocebile nge-kaolin, wokushisa okuphezulu, kaningi okhanyisa ukukhanya.

R₂O ne-RO

Ama-flux e-alkali (Na₂O, K₂O, Li₂O) nama-flux e-alkaline earth (CaO, MgO, BaO, SrO, ne-ZnO).

I-shivering

I-glaze ixebuka emaphethelweni ngoba icindezelwe ngokweqile; iyingozi ezitsheni ezisetshenziswayo.

I-silica (SiO₂)

Okwakha ingilazi; ibizwa nangokuthi i-flint noma i-quartz.

Isilinganiso se-silica ne-alumina (silica to alumina ratio)

I-silica ihlukaniswe nge-alumina ku-unity formula: esiphezulu sivame ukuya ekucwebezeleni, esiphansi ku-matte.

I-slip ne-engobe

Ubumba emanzini; i-engobe yisembozo esifana ne-slip esinezinto eziningi ezingebona ubumba.

I-specific gravity (SG)

Isisindo se-slurry uma siqhathaniswa nevolumu efanayo yamanzi. Izincwadi ezindala zase-UK: pint weight.

Okusimamisayo (stabilizer)

I-oxide, ikakhulu i-alumina, eqinisa okuncibilikile futhi yengeza ukuhlala isikhathi eside.

I-stoneware

Umzimba wokushisa okuphakathi kuya kokuphezulu (cishe i-cone 5–10) oba yi-vitreous noma ucishe ube yiyo.

I-thixotropy

Ukugeleza uma kugovuzwa, ukujiya kube yi-gel ethambile uma kuthule.

I-underglaze

I-slip enombala noma umhlobiso we-oxide, ngokuvamile ngaphansi kwe-glaze ecacile.

I-unity molecular formula (UMF, Seger formula)

Ama-oxide e-glaze njengezibalo zama-molecule, kulinganiswe ukuze ama-flux ahlangane abe ngu-1.

I-vitrification

Umzimba uba njengengilazi futhi ungabi nazo izimbobo ezincane lapho ushiswa.

I-wax resist

I-wax ependwa lapho i-glaze kungafanele iye khona, ngokuvamile onyaweni.

I-whiting

I-calcium carbonate, i-flux enkulu ye-calcium; ilahlekelwa ngaphezu kuka-40% wesisindo sayo lapho ishiswa. NgesiJalimane: Kreide.

Imithombo

• Glazy Help: Glaze
• Glazy Help: Oxides
• Glazy Help: Raw materials
• Glazy Help: Glossary
• Glazy Help: Analyses
• Glazy Help: Firing
• Glazy Help: Defects
• Glazy Help: Specific gravity
• Orton Ceramic Foundation: Pyrometric cone chart, °F (via The Ceramic Shop)
• Digitalfire: Bisque
• Digitalfire: Bentonite
• Digitalfire: Unity molecular formula
• Digitalfire: LOI
• Digitalfire: Frit
• Digitalfire: Limit formula
• Digitalfire: Glaze crazing
• Digitalfire: Glaze shivering
• Digitalfire: Specific gravity
• Digitalfire: Oxidation firing
• Ceramic Arts Network: Common glaze faults and how to correct them (Linda Bloomfield)
• Ceramic Arts Network: An introduction to color (Birdie Boone)
• Ceramic Arts Network: 8 ways to apply glaze (Robin Hopper)
• Glendale Community College: Glaze color
• Potclays: The difference between stoneware and earthenware
• US FDA: Compliance Policy Guide Sec. 545.450, Pottery (ceramics), lead contamination
• EUR-Lex: Council Directive 84/500/EEC of 15 October 1984 on the approximation of the laws of the Member States relating to ceramic articles intended to come into contact with foodstuffs
• eCFR: 21 CFR 109.16, Ornamental and decorative ceramicware