firing glazed bottoms

[kellijaebaeli]

I've seen versions of this question all around the Internet, but none of the answers address the situation for me. Unglazed bottoms or feet are fine for artistic pieces, but what about pieces that are functional/food and beverage oriented, like plates, cups, items to place in aquariums, etc.? i NEED to glaze the whole piece. As you all know, this is a problem since the glaze sticks to stilts, and grinding ruins the fully-sealed coverage of the glaze on the bottom. Is there a certain kiln wash for the silts? a certain type of fire brick where the glaze won't stick? any way at all to glaze fire without making marks or having to grind pieces? Alternatively, are unglazed bottoms okay for washing or submerging in water?

[liambesaw]

Unglazed bottoms are 100% fine for functional ware.

For pieces being submerged in an aquarium you can seal them in other ways. If you can high fire some porcelain it will vitrify 100% and be sealed.

[Tyler Miller]

On stoneware/porcelain there is no need to glaze foot rings/bases, on earthenware pieces it’s better for piece longevity if you do.  Based on your other post’s mention of a low fire body, i suspect this is the reason you’re looking for a glazed bottom.

Stilts are generally the way to go, but since that option isn’t working for your particular application, another option might be to terra sig the foot ring—something some low firers do sometimes.

There is an article mentions the process in passing:

https://ceramicartsnetwork.org/daily/pottery-making-techniques/ceramic-glazing-techniques/the-magic-of-majolicamaiolica-how-to-create-vibrant-painterly-decoration-on-pottery/

 

[JohnnyK]

What do you call stilts? Are they the stilts used to support shelves or the devices with sharp metal spikes that are used for supporting low-fire pieces? If the former...fuggetaboutit! If the latter...there shouldn't be a problem for either functional or decorative pieces since the marks are so small and would be in a place that spends most of its time out of sight.

JohnnyK

[Benzine]

52 minutes ago, JohnnyK said:

What do you call stilts? Are they the stilts used to support shelves or the devices with sharp metal spikes that are used for supporting low-fire pieces? If the former...fuggetaboutit! If the latter...there shouldn't be a problem for either functional or decorative pieces since the marks are so small and would be in a place that spends most of its time out of sight.

JohnnyK

Good point Johnny.  When I first started working with clay, I heard people use the word "Stilts" for both things.  I don't know if traditionally, it is acceptable to use the term for either, or if it's just something that some have learned, and then continued to propagate?

For me, the little ceramic and wire stands, that raise projects off the shelf, are "Stilts".  The shelf supports are "Posts".

 

In regards to marks left, from the stilts on a glazed bottom, they can be ground down, with sandpaper or a sanding disc, without exposing any of the bare clay.  There are also these:

https://www.continentalclay.com/detail.php?cat_id=413&sub_categoryID=167&PID=905

 

This is what I use in my classroom, to remove stilt marks.  They work well, and are inexpensive.  In fact, at between $3-4, and the fact that I've had the same one for several years, it's a great deal.  It will probably still be in my classroom, when I retire, and be no worse for the wear.