crazing, always bad?
Posted 11 May 2013 - 03:39 PM
Two skilled pros in the area sell dinnerware that is uniformly crazed, and it always bothers me. They both maintain stoutly that the crazing in no way effects the safety of the ware.
I was taught was back when that crazing indicates a poor clay-glaze fit, period, and that a crazed glaze is going to stain easily and trap food, drink, whatever. In short, that crazing is a defect.
Thanks in advance. I know this is an amateur's question, but that's what I am, and so I ask it.
Posted 11 May 2013 - 04:45 PM
Anyone who is woodfiring in open stacking will have at least some crazing in the applied and natural deposit glazes........ nature of the beast.
There are a lot ot threads here that discuss this topic.... read around a bit in older threads.
Crazing DOES mean that there is a different Coefficient of (reversible) Thermal Expansion (COE) between the clay body and the glaze. Crazing DOES make the wares weaker than the same wares would be with a glaze where the body and glaze COEs matched.
As to if that makes the ware "unsafe".... only you can make that decision for your own work or for work that you might purchase.
Teaware people deliberately LOOK for craze lines in pieces to stain in over time.
Do also note that the standards for restaraunt wares in most places in the USA prohibit crazed wares (but often allow porous wood food utensils.... go figure).
And note that the FDA does not prohibt crazing on tablewares...... they just set standards for lead and cadmium release on such pieces.
Professor of Ceramics; New Hampshire Insitute of Art
Guest Professor, Wuxi Institute of Arts and Science, Yixing, China
Former President and Past President; Potters Council
Posted 11 May 2013 - 05:33 PM
For a number of years, I used three, and only three, glazes delivered pre-formulated in bags from a potter up the road. Add water, presto. Cone 6, gorgeous, durable, and never a bit of crazing.
Now I am mixing my own... It just seems to me that there should be a straight-forward answer to the safety issue. Crazing over stoneware is safe, or it isn't, Japanese, Chinese, Korean traditions notwithstanding.
Again, many thanks for the benefit of your experience.
Posted 11 May 2013 - 06:17 PM
Here is my cents....
Crazing also weakens structural integrity as opposed to same not crazed piece.
Ask me how I know........
As much as I could tell the few pieces I've dropped and broken. All cracked up on craze line....... It is a small crack after all
From a sanitary / food handling safety perspective (which I have much experience). The tine cracks have a higher propensity to harbors bacteria. However Appropriate/ PROPER. cleaning and sanitizing will fix Most issues.
Your probably not going use good pottery to handle raw meats and or seafood, So risk level drops with cooked food.
Googlembleahnto water ratio. An allow to air dry.......
I'm an aspiring chajin or tea person. So I love me some crazing. And formulate a few glaze clay combo to craze.
Look left or go to gallery guinomi is crazed since I'm the only one drinking out of it and its usually and adult beverage. I don't sanitize, Just a little soap and water.( living on the wild side)
The beige is blinding!!!!!!
The middle of the road is boring
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Posted 11 May 2013 - 06:29 PM
i have one plate from a set of commercially made dinnerware someone used in the microwave. it has concentric circles of cracks which have gotten increasingly dirty looking over the 10 years since it happened. i keep that plate on the bottom of the stack of 8 plates in case someone comes over for dinner. it is hardly ever used and if it is, i make sure i get it. yuk
Corelle ware is made for microwaves, i won't use good stuff.
how about using matte glazes on plates? yuk sound of silverware scratching it and yuk black metal marks.
Posted 12 May 2013 - 09:20 AM
i read somewhere that health inspectors do not approve of crazed dinnerware in restaurants because it is unsanitary.
Yeah, my son is trained as a chef, turns up his nose at some of the crazed dishes we have around-heirlooms from generations back.
Posted 12 May 2013 - 11:26 AM
Contemporary Fine Colored Porcelain
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Posted 12 May 2013 - 11:48 AM
The crazing question always runs in a circle with no good answer. I have read that crazed areas are too small for bacteria to grow ... Even bacteria need space. I have read that this crazing harbors all sorts of awful stuff. What I believe is you are probably 1,000 times more likely to get sick from the food than from the plate it is on.
Not only that, but you are also probably, more likely to get sick, from the hands you use to prepare and eat the food as well.
Posted 12 May 2013 - 03:43 PM
you are probably right, but I still worry about it when you can see the crud in the cracks.
I sometimes wonder if we haven't overdone the sanitation thing in the last 5 years. All of these hand sanitizers and wipes, are removing our ability to fight off a bug, but then the bugs have gotten worse. That brings to mind which came first the chicken or the egg dilemma.
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