For every mile of highway there is two miles of ditch! If we compare ongoing pottery production toa highway, then many of us spend some time in the ditches with troubles. [tis hard to accept a kiln load of warped, bloated, dunted or crazed ware or a drying rack of cracked pots. [ve seen some potters cry and others go bankrupt when unable to solve a problem. That's why I'd like to promote a middle-of-the- road approach to production practices and an understanding of the trade-offs of your process and materials. If you think you have a process or a clay body that enables you to break the males, think again. Materials, bodies, and your process vary; you need to have some mar- gin-for-error t prevent problems. The aivure of ceramics be that (yee de yvaur best and your suppliers de their best, there well aril be prablents, For the sake of argument, lets assume you're in trouble. You think the clay is the problem. You need to solve the problenn. Let's consider some viewpoints that can getin the way. I've ulways done things the same and now there is a problem; it is not my fault, Have you really always dome it this way’? Are there changes you have overlooked? isthe way you have always dome it the best way? If you have been driving on the shoulder by taking shortcuts in the form- ing, drying or firing process, then is being in the ditch a surprise? Is it possible thal ne supply company can deliver the kind of consistency that your push-the-envelope process requires’? We are too busy; we don't have time to change our process. By understanding every detail of the proc- ess and optimizing accordingly, industry has figured out how to fire ware in less ihan a hour cold to cold. Maybe you could analyze your situation and solve the prob- lem and cut time, Clay manufacturers are happy to help. Call them early. Kememm- ber, each clay has a complex personality. Itis offen better to work out the proflem than start over with a new body, However be ready to switch ifan evaluation demon- stries the need. September 200] TECHNO TIP I’ve Always Done [t This Way! il worry about making the ware; the clay manufacturer can worry about keeping the clay consistent. First, are you paying due attention to mak- ing the ware? What condition 1s your kaln in? Does it fire evenly? Do you really know what temperature it fires to? How do you dry ware? Do you stress test your glaze to make sure it won't craze and pieces won't crack on sudden heating or cooling’? Second, how trusting are you? At Plainsman Clays we've been burned enough times that we cannot afford to take this view with our refined clay suppliers, We do test cach clay body run for many physical properties and compensate reci- pes io smooth out vanations. Bul we donot test for things like thermal expansion, ul- limate particle size, Chemistry, and miner- alogy. If you like to run your business on the shoulder of the highway, variations in these could put you inte the ditch. I don’t need to know that technical stuff; just give me a good clay and glaze recipe and [ll do the rest. How do you know what to do in the event of a problem if you don’t know technical stuff! Doing the rest involves dealing with varialions in Your process. Ive heen potting for 20) years; I know what I am doing. Old habits die hand and can bring trouble. No matter what expenence you have, the wise course is bo be open to Logical reason- ing on why you should do something dif- ferently. Depending heavily on a tradi- tional but shaky technique wall bring aday of reckoning, So-und-so said this is my problem. Did they explain logically why? This body is crazing my glazes. Glazes craze because their thennal expan- sion does not match the body. You have to change one of the other. Firing slower just hides the misfit problem; time will display it. There is only one fix: adjusting the thermal expansion of a glaze, Il is easy. You should be using an adjustable glaze so you can fine tune on an ongoing basis. You showld be doing ice-watercbenling-water testing. Check digitalfire.com for more information. Pouers Guild of British Columbia Newsletter Do you understand the tradeoffs of your body and process? For example, vitreous bodies tend to warp. Vitreous stonewanes may tend to bloat on overfiring, Highly Plastic ones tend to crack on drying. Po- rous functional ware bodies wil] Jeak and break casily. Low silica or high feldspar glazes contribute (0 crazing. Misfitted glares severely impact ware strength, etc, Understanding your clay body and being in contact with the manufacturer is good. Plainsman Clays, for example, publishes very detailed body data sheets al its website ww plainsmancliys com You are free io email any time abowl a body problem; deat suffer and suffer with- out secking help. We are all going to weave on the one-way highway of ceramic production, but if you are near the middle you will stay out of the ditch. Tony Hansen Digitalfire Corporation httpfdigitalfire.com Calculation! Database Software for Ceramic Industry Techno Tips are written by Tony Hansen with the support of Plainsman Clays Limited tn Medicine Hart, Alberta. Greenbarn Potters Supply in Surrey, anal Vancouver Island Pottery Warehouse Inc acer Nancie are (peal affiliates.