Is crazing in pottery bad?

Is crazing in pottery bad?

Technically crazing is considered a defect in the glaze and can weaken the item. It may also harbor bacteria. So if you are buying pieces to use for serving food you should look for uncrazed pieces. It sits between the lines or in the clay under the glaze so cannot be removed by scrubbing the surface.

What is meant by crazing?

Crazing refers to a network of visual cracks on a coated metallic surface. It occurs due to tension stresses in some glassy thermoplastic polymers. Crazing is propagated in metallic surface regions that experience high tension and leads to the formation of microvoids and small cracks.

How do I stop my glaze from crazing?

To reduce crazing:

1. Increase silica and clay by 5% silica and 4% clay.
2. Add 5% talc or zinc oxide.
3. Substitute lithium feldspar for sodium feldspar.
4. Substitute borate frit for high-alkaline frit.
5. Apply glaze thinly.
6. Increase firing temperature.

Can you still use dishes that have crazing?

Crazing on dinnerware pieces is never okay You may have heard it called crackling or even, heaven forbid, grazing. Most collectors use pieces as display-only and therefore accept crazed pieces into their collection though as a general rule, crazing isn’t a good thing.

How do you test for crazing?

Overview. This test method is for the determination of the resistance to the formation of crazes by subjecting whole tiles to steam at high pressure in an autoclave, then examination of the tiles for crazes after applying a stain to the glazed surface. Crazes show as fine hairline cracks, limited to the glaze surface.

Can crazes carry load?

A craze is different from a crack in that it cannot be felt on the surface and it can continue to support a load. Furthermore, the process of craze growth prior to cracking absorbs fracture energy and effectively increases the fracture toughness of a polymer.

What are the examples of craze?

When everyone suddenly becomes obsessed with a hot new band that came out of nowhere, this is an example of a craze. Craze is defined as to become wildly excited or insane. A fan of an actor who becomes obsessed and stalks the actor is an example of craze by a fan.

What is crazing in polymers?

Polymers. Crazes generally propagate perpendicular to the applied tension. Crazing occurs mostly in amorphous, brittle polymers like polystyrene (PS), acrylic (PMMA), and polycarbonate; it is typified by a whitening of the crazed region. The white colour is caused by light-scattering from the crazes.

What is the boundary between crazing and crack in polymer?

The boundary between crazing and surrounding bulk polymer is very sharp, the microstructure of which can be scaled down to 20Å or less, which means it can only be observed by electron microscopy. A craze is different from a crack in that it cannot be felt on the surface and it can continue to support a load.

What happens first cavitation or crazing in polymer?

If, however, the crystals in a polymer are thick and more perfect then the energy barrier for their deformation is rather high and cavitation starts first followed by crazing. Which failure mode dominates depends on many factors.

What is the relationship between crazing and fracture in thermoplastic materials?

Crazing frequently precedes fracture in some glassy thermoplastic polymers. As it only takes place under tensile stress, the plane of the crazing corresponds to the stress direction.