Talk:Biscuit (pottery)

Moved from bisque

I moved the comments below from the talk page of the article Bisque (pottery).

Biscuit and bisque are utterly distinct pottery items with bisque being a small subcategory of the larger biscuit. Biscuit is any pottery after the first firing and before any glaze is applied. This can be a final product such as bisque, or terra cotta, or an intermediary step in a glazed final product. Since most biscuit becomes either glazed or terra cotta, and only a tiny fraction is bisque it seems to me utterly strange to have biscuit as a paragraph in bisque. Kind of a "tail wagging the dog" situation.

Under the Wikipedia dictate "be bold" I am doing this. If some knowledgeable editor knows of a "standard Wikipedian" way of doing this, which I have violated, please let me know in a kind and gentle way. Nick Beeson (talk) 13:45, 17 July 2015 (UTC)

Use of the term "biscuit"

The use of biscuit for an intermediary stage in the production of multiple fired pottery is not an issue of British / American usage. As illustrated below biscuit is used globally, including the US. It is the most widely used and recognised term.

International

• "New And Latest Biscuit Firing Technology." Ceramic Forum International. 87,No.1/2,2010,p.E33-E34,E36
• "Applying Biscuit Porcelain Articles Using Cup Handles As An Example." D.Erdmann. Ceramic Forum International. 75,No.7,1998. pg. D7-D9.
• "Plates Are Rolling Through The Biscuit Kiln." Ceramic Forum International. 70,No.3, 1993. pg. 110-113.

Australia

• "Physical Properties Of Some Weak Porous Materials. Pt. 2. Comparison Of Fracture Toughness (Kic)Values From Indentation And Compact Tension Methods." R.R.Hughan, M.V.Swain. Ceramics. Adding the Value. Vol.1. Austceram 92. Proc.Int.Ceramic Conf. Melbourne,1992,p.50-53 Australian Ceramic Society. Quote: "The degree to which fracture toughness results, obtained using a WC indenter which produced indentations significantly larger in size than the grains and pores of the porous archaeological materials studied, correlate with a standard technique, namely the compact tension method, was examined. The preparation of the test pieces (terracotta body; quartz-free body; tile biscuit; gypsum plaster) is described."
• Quote: "The glaze is applied to the pot either as a powder or as a suspension in water. This can be done either before the pot is fired or after an initial biscuit firing. The pot is then fired to melt the glaze onto its surface." [1]

Bulgaria

• "Obtaining Of Biscuit Body For Wall Tiles On Kaolin Sand Bases." R.Dimitrov, St.Djambazov. Author Affiliation: Sofia Higher Institute Of Chemical Technology. Paper presented at Qualicer. II World Congress on Ceramic Tile Quality 1992, pg. 205-212. Castellon, Official Chamber of Commerce, Ind.& Nav. Spain.

Canada

• Quote: "First or biscuit fire is at temperature of 1250 degrees C." [2]

Czech Republic

• "Moisture Expansion Of Porous Biscuit Bodies - Reason Of Glaze Cracking." Ceramics-Silikaty 46,No.4,2002, pg.159-165

France

• "Biscuit Firing Of Porcelain Plates Manufactured By Isostatic Pressing." G.Coudamy. Author Affiliation: Coudamy SA (a French company). Ind.Ceram. No.855, 1990. pg. 806-809.
• "Firing Of Porcelain In Polyfunctional Intermittent Kilns Of Large Dimension With Controllable Atmosphere." Author Affiliation: Pillivuyt (a French company). Ind.Ceram. No.841, 1989. pg. 634-635. Quote: “The Pillivuyt firm at Mehun-sur Yevre, near Vierzon, introduced new gas fired intermittent kilns which are suitable both for biscuit firing and for glost firing of porcelain tableware.”

Germany

• "Emphasis On Flexibility - Biscuit Firing In A Roller Kiln." H.Schmidt,K-H.Schoppe. Interceram 41, No.4,1992. pg. 284-285.
• "Automation In The Tableware Industry: Roller Kilns For The Fast Biscuit Firing Of Porcelain." A.Avallone. Interceram 44, No.3,1995. pg186-188.

Hungary

• "Size And Shape Of Wall-Tiles, Depending On Biscuit Firing Conditions." M.Lenkei, Z.Bansaghi. Epitoanyag 33, (4), 140, 1981

India

• Quote: "Biscuit waste called as biscuit pitcher is recycled in the composition in the range of 5 to 10 wt%." [3]
• Quote: "Unit 7: Drying of ceramics, Biscuit firing and glost firing, fast firing technology, action of heat on triaxial body, Elementary ideas of various furnaces used is ceramic industries." [4]
• Quote: "The most important aspect of the entire tile making process is grinding of the sand and biscuit preparation." [5]

Italy

• "Roller Kilns For The Fast Biscuit And Glost Firing Of Porcelain." Ceramica Informazione. 20 ,No.202, 1994. pg25-27.
• "Crawling - A Serious Defect In Glazes After Firing.’ S.K.Mukherji, B.B.Machhoya, R.M.Savsani, T.K.Dan. Ceramurgia 23, No.6, 1993, pg.269-275. Quote: “Crawling of a zircon-opacified glaze on a stoneware support was investigated. Crawling set in after grinding the glaze to below a certain particle size. Excessive viscosity of the molten glaze at the maturing temperature causes crawling. The ideal viscosity is 2400 poise. The surface tension of the mature glaze should not be too high. It should be kept to 290-300 dyne/cm by suitable additives. Factors casing poor adhesion of the glaze and thus crawling are listed and preventive measures are suggested. The biscuit fired base should not be too porous, the glaze should be applied uniformly and the coating should not be too thick.”

Japan

• "Effect Of Biscuit-Firing Conditions On The Crazing Resistance Of Vitreous Chinaware. (Studies On The Glaze Fitness Of Porcelain Ware, No.7)" H.Inada. Journal Ceramic Society of Japan. 86, (994), 284, 1978.

New Zealand

• Quote: "However, a small number of articles are fired twice in a method whereby the glaze is applied after the first, biscuit, firing and is fixed on by a second, glost, firing." [6]
• Quote: ".. each piece dries extremely slowly before a biscuit firing .." [7]
• Quote: "He makes the ceramic tiles by cutting shapes from rolled out clay, biscuit firing them .." [8]
• Quote: "The pore water will only leave the clay above 100 °C during the smoking period of biscuit firing." [9]
• Where I am writing this from!!!

Taiwan

• "Two-Dimensional Computer Simulation Of Biscuit Firing Process Of Wall Tiles In The Electric Tunnel Kiln." J.Wu, H.Yin, Z.Lin. J. Chin. Silic. Soc. 15, (5), 425, 1987.

Thailand

• Quote: "Step 8: The next step is biscuit firing. The products are fire at the temperature of 800ฐC for 6-8 hours. The purpose is to harden the clay so that it is easily glazed." [10]
• Quote: "Batts/supports systems, roller kiln batts, plate saggars for porcelain glost firing, profile setters for bone china biscuit firing and cranks for decoration firings belong to the wide range of kiln furniture products which characterize this industry." [11]
• Quote: "Strength is provided by the fusion of body ingredients during firing. This unique English pottery body is made from the following: 50% animal bone , 25% china clay , 25% china stone . First or biscuit firing 1200 C - 1300 C. Second or glost firing 1050 C - 1100 C." [12]
• Quote: "One time biscuit firing will cost 3500 baht and glaze firing (not more than 1280 C) will cost 5000 baht." [13]
• Quote: "A fritted clear glaze of five different average particle sizes was applied to the biscuit-fired body and gloss fired at 1000 °C for 60 minutes in an electric furnace." [14]

Turkey

• "Interactions Between A Leadless Glaze And A Biscuit Fired Bone China Body During Glost Firing. Pt.3. Effect Of Glassy Matrix Phase." A. Kara. Author Affiliation: Anadolu University, Eskisehir, Turkey. Journal of The European Ceramic Society. 23, No.10, pg.1617-1628. 2003.

USA

• "The Automatic Clay Shop Of The Future." G.J.Croninger. Proceedings of The American Ceramic Society. An. Meeting and 1977 Joint Fall Meeting, Mater. and Equipment and Whitewares Divs. Edited by W.C. Mohr. Columbus, Ohio, ACS, 1977. pg.25. Quote: "Developments in the last 40 years towards fully automated tableware production are discussed, dealing with the stages from sliphouse to biscuit kiln, followed by automatic methods of biscuit ware cleaning, glazing, setting and packaging."
• "Mechanical Properties And Hydrothermal Stability Of Porous, Partially (Biscuit-) Sintered Y-Tzp Ceramics." T.Kosmac, M.Andrzejczuk, K.J.Kurzydlowski. Mechanical Properties and Performance of Engineering Ceramics and Composites II. American Ceramic Soc.Inc. Proc.30th Int.Conf. Cocoa Beach, 22-27 January 2006, p.83-92.

Uzbekistan

• "Influence Of Biscuit- And Glost-Fired Recycled Rejects On The Porcelain Formation." A.M.Eminov, G.N.Maslennikova, H.M.Nabijev. Author AffiliationTashkent, Chemical Technology Institute. Keram.Z. 51,No.3,1999, pg.188-189. —Preceding unsigned comment added by 210.54.238.178 (talk) 23:48, 17 June 2010 (UTC)

Despite all of your examples, most of them European, when American potters write and discuss this method they most often use the term "bisque." I trained at two universities in the western US and "bisque" was the term used in lectures and expected in papers, as well as in common studio usage. The only people at the universities, and those who gave workshops and visited the studio, who used "biscuit" were educated/trained in Europe or, in one case, Australia. So, the usage of bisque is not "confusing" to me or to most of the potters I work with. This article should reflect both usages, and one usage should not be denigrated. WBardwin (talk) 00:11, 18 June 2010 (UTC)

Hi -

The examples are of global origin. They are from 15 countries of which 10 are non-European.

"This article should reflect both usages .." The last edit of mine reflects both usages.

".. one usage should not be denigrated. " No usage is being denigrated.

On an edit summary you claimed 'biscuit'/'bisque' was an issue of British / American usage. The references above clearly indicate otherwise. Also, you have now acknowledged this with " used 'biscuit' were educated/trained in Europe or, in one case, Australia."

Biscuit is by far the most common: see references.

I do not understand the significance that you "trained at two universities in the western US." —Preceding unsigned comment added by 210.54.238.178 (talk) 01:04, 18 June 2010 (UTC)

I have some sources on the origin of the two words -- both derive from the same term. The use of "bisque" for non-glazed porcelain figurines, which use the above anon editor want to see dominate, is actually historically quite late, coming in to use in about the 1700's-1800's. The use of bisc, bisque, or biscuit (yes, even another term) for partially fired/immature pottery ware is found much earlier in history. The two or three terms have often been used synonymously and are currently used correctly by both factions. The apparently objectionanble usage, however, does seem to be generally drawn by country of origin/education, with particularly the midwest and western US using the term slightly differently. BUT -- this pattern of usage is not "confusing" to the educated (or willing to be educated) reader. Labeling one usage "confusing" begs the question - "Confusing to whom?" The label is denigrating a particular usage, in my opinion. I will remove that usage. WBardwin (talk) 03:31, 18 June 2010 (UTC)

Hi,

To describe an intermediary stage in the production of multiple fired pottery biscuit is considerably more widely used than bisque, and this includes in the USA. Whereas bisque is the accepted term for a type of porcelain. The latter being unglazed porcelain used for the final products, such as dolls heads and figurines. These are different usages, and to use the same word (bisque) for both is "confusing", and in my opinion this is not denigrating a particular usage - please do not remove it.

"The apparently objectionanble usage, however, does seem to be generally drawn by country of origin/education, with particularly the midwest and western US using the term slightly differently." References please.

"..coming in to use in about the 1700's-1800's" This could be an interesting addition, providing all has the necessary referencesare included. But it does not, of course, alter what is the most wide spread term in use now.

Underneath are eight further references for non-European biscuit: 4 different countries and 3 different professional ceramic organisations, inc. The American Ceramic Society.

Asia - country not specified

• "Bones Of Contention." D. Slinn. Asian Ceramics. April,2004, pg. 26-27,29,31. Quote: "The status of the bone china industry is examined .. Asian manufacturers initially used calcium pyrophosphate together with CaCO3 in their bodies, but are now moving back to natural bone ash since it improves the firing properties and helps to maximise biscuit yields."

Canada

• "Preparation Of Frit/Glaze From Drum Filter Cake - A Waste Generated By The Secondary Zinc Industry." S.Bhasin S, S.S.Amritphale, N.Chandra. Journal Of The Canadain Ceramic Society. 69,No.2,2000,p.27-30. Quote: ".. The frit material was powdered and after mixing with clay was used for glazing biscuit fired unglazed ceramic tiles."

India

• "Facing Tiles On Low Melting Clays." L.Bozadgiev. Indian Ceramics. 38,No.3,1995,p.38341-38343. Quote: "Bodies based on a mixture consisting of sandy clay and calcareous clay (3:2) for facing tiles were prepared. The tiles were pressed at 25 MPa using a body with 8% moisture and dried at 110 C for 2 h. Biscuit firing was performed at 1000 C for 1 h and glost firing at 950 C for 1 h."
• "Characterisation And Utilisation Of Wood Ash In The Ceramic Industry." S.K.Mukherji, T.K.Dan, B.B.Machhoya. Indian Ceramics. 38,No.3,1995,p.38327-38331. Quote: "Wood ash was prepared by burning Neem wood, which is abundant and has many advantages (fine particle size and high reactivity due to its amorphous nature). Several experiments were conducted to ascertain its suitability for use in the ceramics industry .. results indicate that glazes and colours developed using wood ash can be used on both green and biscuit wares."
• "New Ways For The Production Of Tableware. Reflections Of An Engineer." K.H.Schoppe. Indian Ceramics. 38, No.3,1995,pg.38305-38307. Quote: " .. the combination of biscuit roller kilns and glost (fast firing) tunnel kilns are state-of-the-art. The process takes about 12 h from shaping to finished ware. The layout provides flexible, semi-automated efficient mid-sized production units which are adaptable to market demand."

Japan

• "Consideration About The Glazing To The Bone China." Ichiko T. Journal Of The Ceramic Society Of Japan. 102,No.5,1994,p.471-475. Quote: "The mechanical properties of bone china were evaluated in relation to the method of the glazing, to the different Quote: "body states and the different glaze compositions. The glazing was conducted by application to the green body, the biscuit body fired at 800 C and the sintered body fired at 1240 C."

United States

• "Automated Flatware Production." A.K.Devon, S.G.Lunt. The American Ceramic Society Bulletin. 73,No.9,1994,p.88-91. ".. A fully automatic handling system is employed. A three-tier gas-fired roller hearth biscuit kiln is used, capable of firing 20 tons/day at 950 C. The ware is fed automatically to the glazing lines, each of which has an automatic backstamping machine with brushing and dusting facilities. Glost kiln placing has yet to be mechanised and automated."
• "Effects Of Glazing Technologies On Tile Surface Properties." L.Esposito, A.Tucci, G.Timellini, A.Fontana. The American Ceramic Society Bulletin. 73,No.8,1994,p.53-56. Quote: "A white tile glaze was applied to biscuit tiles wet, by bell application, dry, by mechanical spreading vibrating sieve apparatus and electrostatically, using microspheres." —Preceding unsigned comment added by 210.54.238.178 (talk) 04:52, 18 June 2010 (UTC)

There is clearly no editorial agreement on usage, "bisque" or "biscuit", so the proper course of action is to include both, with references for each. I have made the appropriate changes. Marshall46 (talk) 14:23, 31 March 2011 (UTC)

Terracotta

Terracotta should not be highlighted as it is not infrequently glazed. For example, from a quick Google search: [15], [16], [17], [18], [19], [20], [21], [22], [23], [24] — Preceding unsigned comment added by 81.136.49.89 (talk) 19:45, 7 June 2016 (UTC)