the formation of porcelain. Such purity in dlay is very easily deflocculated and makes excellent casting slip. Many beige tones in stoneware clays, cast well when deflocculated. Manufacture of Earthen- ware slip: In dlay, feldspar, is a minerai containing specific cheuîtilcal formulas of alumina and silica combined with lime, potash and soda. This is found in a delicate balance here in water, flint and sodium silicates. The dlay mixture, once obtained is dried in a plaster tube tiii it is hone dry. To ensure complete drying an oven is used. The dry dlay is then passed through a fine mesh screen and placed in a mor- tar for grinding to a fine powder. This powder is ad- WHITBY FREE PRESS, WEDNES[)AY both substance are found in todays manufactured slips. Some dlay types do not respond to these compounds readily, so other com- binations are used. Sodium hydroxide, is a strong runny caustic solution. Lastly sodium pyrophosphate, and tetrasodium tannate are organic compounds which have been used. It is flot possible to use al type of dlay in defloc- culation. Surface clays con- tain considerabie amounts of iron or free aikali. Clays which are purest in com- position contain less iron and more alumina. Even kaolin, the purest form of clay is similar to the earth's crust when it is pulverized by erosive action. Kaolin, is a pure, whitening dlay. It is used in 1 ded to a calculated, propor- tional amount of water, tîlI a paste forms. Drop by drop the deflocculent is added tili a desired consistency is reached. Following the specific combination of all substances, to create the slip, it is ieft to stand for ob- servation. Should it tend to gel, more deflocculent is ad- ded. An essential quality of slip is that it remains fluid when unagitated. The slip is poured into moids for its final test. At this point it is impor- tant to understand that we do not add water to slip to upset its balance. Following mold casting it is flot ad- visable to reclaimn disgarded pieces. It is difficuit to return the calculated balan- ce to the slip as some defloc- culent has absorbed to the mold plaster. Eventualiy the reciaimed slip displays a MARCH 26, 1980, PAGE '413 brittie more fragile quality in greenware. Watered down slips produce cracked or warped greenwarc, on its removal from the mold, and could resuit in warping from shrînkage. Deiayed cracking is the glaze surface may occur up to two years after a piece is completed. With uneven drying after firing occurs minute amnoun- ts of moisture existing beneath the glaze surface are subject to expansion and contraction with tern- perature changes. Pressure increases under the glaze to ailow this moisture to escape, and delayed crazing occurs. Remnember to send questions, comments and problems in to us and we'l do our best to help you out. Till next time when we look at difficulties when cleaning greenware. M.'lanstram Cnada Street people are feet LMantem aajpeople. They're neat people LIZ RANKIN To quickly acquire a knowledge of the process of creating ceramics, and the importance of certain steps, it becomes necessary to look at the creation of slip and the subsequent greenware. In creating a cast dlay body, we examine' the physical characteristics of casting slips. The slip itself, if a combination of dlay and chemnical substances, in- voiving an electro-magnetic suspension. The clay for the most part is composed of silicate of alumina. This is the substance which becomnes plastic when wet and rocklike when fired. Good quality slip, for the purpose of creating green- ware, flows reaclily into and out of a mold leaving a smoot.h, uninterrupted sur- face. The dlay content of the slip should neyer, settle to any area of the mold on pouring. Nor should dlay set- tde to the bottom of a con- tainer, during storage, dispiacing water to the sur- face. Water content should be relative to the mixture, but not excessive as it will saturate molds. Controlled water content will facilitate the release of the cast pieces from the moid. Minimal shrinkae wilI occur upon drying. When trying to create a slip substance by simply combing clay and water, one finds that too much water is necessary to make a flowing solution. It becomnes ap- parent that the dlay par- icles tend to "flock" together and settle to the bottomn. The solution con- tinually acquires lumps and bumps. If used in a moid, this solution would leave rough areas where it was drained. Evaporation of the excess water when drying, would cause pronounced deformity in size and shape. The dlay would stick to saturated areas in the mold, making removai of the item strenuous. Therefore, it is necessary to reduce the water content in clay. This step is calied defiocculation, and is achieved by a chemical bond. Between alI particies there is some form of elec- tricai attraction on a basic chemical level. This attrac- tion also occurs between dlay molecules. To disperse the dlay flocks, so each par- ticle floats on its own, we add an electrolyte, sodium silicate or soda ash. This aikali substance alters the existing electrical charges in the clay/water balance. Molecules now repel each other and float freeiy, diminishing the need for ex- cess water. Sodium silicate, com- monly referred to as "wa ter- glass" is a liquid of varying compounds of soda and silica. Soda ash is a water soluable, crstaline sub- stance. In equal strengths Axeworthy's Big Problem 1hv Roger Il . * Worri Most political pundits in Canada beliee Manitoba's Ll<>%d Axe%%orlh% recei,.ed a second-rate lederal cabinet post, considering fie is one oi' oni> tN%< L.iherais elected irom %Nestern Canada. That's flot the case. ,Aeworth> has heen handed the task of deaiing %ith hat is potentiallN the mosi explo- se political situation in the countri. As Minister <>1 Manpoý%er and Immigration, he is the federal minister responsible for training the tens of thou- sands of skilled tradeN people Canada will require during the nexi decade as the coun- try gets set to spend S200 bil- lio>n on major projects. Roger fiorth ix I)irecror, Piiblic .Affairs, (anadian 1-ederation of Itidependlent Business. And a ses ere shortage of skilled labor alread: exists. Surs cîs conducted h: the 55,000 member Canadian Federalion of Independent Buisiness indicate finding qualified ssorkers lfor rela- tisel% high-paî ing jobs ik arnong the top prohlems iaced h% small and medium- sized er.!erprises. .And the situiation is just as bad for bigger husinesses. D. THAPAR Denture Therapist 214 Dunda St. E, Whiby 66U-7797 HOIJRS: Mon..-Sut.& Evenings By Appointment OnIy STEVEN F. PELESHOK, B.A., LL.B. BARRISTER & SOLICITOR Appolntments Avallable Evenîngs end Saturdays 105 DUN DAS ST.W. TEL.(416 6683616WHITBY, ONTARIO TEL.(416 6683616LlW 2Ml So a crash program too up- grade skills, particoiIarIý among the unempIo:ed, ssill tindotedINhe a prioriti for tlic ness minister. The delicate political problein that is likeI% to de- %elop, though, is somness hat lit terent. If Asessorth> strikes out in efforts to provide enotugh skiiled trades people. he may be forced to alloss more im- migration or permit qualified people go work in the countri on a temporar% hasis, return- ing home %%hen the job is compleied. Such a move ssould he political dynamite. paricu- larly if Canada's high unem- ployrment persists. In short, Axeviorghy has been handed one of the toughest Jobs in the new cabinet, dealing ssith issues that affect the future of the country, and the place (>f Canadian ssorkers in their ossn land. SPRING FLING SALE The annuai Spring Fiing Sale sponsored by the Good Companions Senior Citizen Club of Whitby will be heid in Fairview Lodge Auditorium on Sat. April 12, 10 a.m. to 3 p.m. with the lucky draw at 1:30 p.m. Prizes are a hand-painted decorated table cloth 60 x 80 inches., Ceramic book ends and ash tray; Covered Bun Basket; Tea Cosy; Card Table Cover; and a cushion. Ail are hand crafted. Articles for sale include home-baking; fancy goods; hardware items; plants; white elephant table. Light refreshments wiil be available. oi LADIES NGHT SEAFOOD CARDINAL" Served i n a Cocotte with R ice $6.95 Includes: Soup du Jour and Coffee N Thursday Night OnIy I 601 Dundas Street West, Whitl who meet people. PaqllftIParnp EIMTEUi FLOWEià~* 668-0727 LARGE SELECiON 0F FLOWERING PLà4Nfl AMD GITS FOR EASI'ER FRFSH & SILK FLOW1ERS TOWN E FLOWERS 601 Dundos St. We Whftby ( Town Plaza CFT '4 "VEAL LAZZARELLA" FESTIVAL Veal Parmigiana and Alaska King Crab $8095 Served with Potatoes & Vegetables i ncludes: Soup du Jour, Coffee or Tea Monday to Wednesday OnIy by 668-3277 77 By LIZ RANKIN 1 25TH ANNIVERSARY 1855-1980 THE CORPORATION 0F THE TOWN 0F WHUTBY PUBLIC NOTICE Brooklin Developmnent Agreement TAKE NOTICE THAT tite Council of the Town of Whltby will be holding a public meeting on Monday, March 3lst, 1980 commencing at the hour of 7:30 p.m. ln the councîl chamn- bers of the Whltby Municipal Building to consider the mat- tors related to a proposed development agreement. It is not the Intention of the council to consîder land use designations and other matters related to the draft officiai plan amendment at this timne. Wm. H. Wallace A.M.C.T., C.M.C. Clerk-Adminstrator The Corporation of the Town of Whltby 575 Rossland Road, East Whitby, Ontario. Carîetto IVaverit 'e Mme à a