majolica

[mannmade]

I needed a new diversion. Been working at the same thing too long. So, I ordered Amaco Opaque white LG11 and some Amaco majolica gloss colors to try some functional stuff. I was reasonably happy with the results for a first try -- it will get better as I practice. Everything was thrown but I added handles on 2 pieces and in both cases, the glaze popped off the handles after it was vitrified or out of the kiln. Bisqued to 04 and fired to 05. I damp sponged the pieces before dipping in Opaque white -- maybe I missed the handles. Anyone have a suggestion?

[Lucille Oka]

Because you said you ‘dipped the ware into the glaze’, I am assuming that you used the underglaze and glaze on bisque ware. Handle the bisque ware as little as possible when you are preparing to use underglaze or glaze. Be sure that your hands and sponges are clean. Any oils having contact with the ware from your hands or sponges or from where ever will create a resist on the ware and the underglaze or the glaze will not stick to the surface. If needed, you can do a touch up and re-fire.

[Marcia Selsor]

At a workshop with Rosie Wynkoop, she suggested sanding down any sloppy spots to rough edges, then washing your bisque with vinegar /water solution before glazing.

 

Marcia

[ceramicfundamentalist]

I needed a new diversion. Been working at the same thing too long. So, I ordered Amaco Opaque white LG11 and some Amaco majolica gloss colors to try some functional stuff. I was reasonably happy with the results for a first try -- it will get better as I practice. Everything was thrown but I added handles on 2 pieces and in both cases, the glaze popped off the handles after it was vitrified or out of the kiln. Bisqued to 04 and fired to 05. I damp sponged the pieces before dipping in Opaque white -- maybe I missed the handles. Anyone have a suggestion?

 

 

do you mean that razor sharp little bits of fired glaze popped off after the glaze firing? if so, that is a condition called shivering. it comes about because the clay body and fired glaze have different coefficients of expansion. as the pieces are cooling down in the kiln the clay shrinks more than the glaze and the glaze no longer fits on the clay. little shards of glaze pop off the pot to relieve the pressure. there is not much you can do about it except to alter the recipes of your glaze and/or clay (but it sounds like you are using pre-mixed clay and glaze) or to use a different clay or glaze.

 

i have a similar problem with my white glaze and terra cotta body, but fortunately it is not a combination i use too often. if i can keep the glaze a bit thin then i seem to have a better chance of my piece coming out ok. also, your form might have something to do with it - shivering tends to occur at sharp edges on lips and handles. if you make those edges a little fuller and rounder it might have a positive effect.

[mannmade]

Yes, it was shivering. Only happened on the handles and not the body of the pieces. The handles were very rounded -- one was shaped like a chili pepper -- but I guess they could have cooled faster than the rest of the pot. Thanks for your help.

 

do you mean that razor sharp little bits of fired glaze popped off after the glaze firing? if so, that is a condition called shivering. it comes about because the clay body and fired glaze have different coefficients of expansion. as the pieces are cooling down in the kiln the clay shrinks more than the glaze and the glaze no longer fits on the clay. little shards of glaze pop off the pot to relieve the pressure. there is not much you can do about it except to alter the recipes of your glaze and/or clay (but it sounds like you are using pre-mixed clay and glaze) or to use a different clay or glaze.

 

i have a similar problem with my white glaze and terra cotta body, but fortunately it is not a combination i use too often. if i can keep the glaze a bit thin then i seem to have a better chance of my piece coming out ok. also, your form might have something to do with it - shivering tends to occur at sharp edges on lips and handles. if you make those edges a little fuller and rounder it might have a positive effect.

 

[mannmade]

At a workshop with Rosie Wynkoop, she suggested sanding down any sloppy spots to rough edges, then washing your bisque with vinegar /water solution before glazing.

 

Marcia

 

 

Marcia,

Thanks so much for your input. I would like to try the vinegar wash. Could you tell me the concentration? Was it plain white vinegar?

[Marcia Selsor]

At a workshop with Rosie Wynkoop, she suggested sanding down any sloppy spots to rough edges, then washing your bisque with vinegar /water solution before glazing.

 

Marcia

 

 

Marcia,

Thanks so much for your input. I would like to try the vinegar wash. Could you tell me the concentration? Was it plain white vinegar?

 

 

yes plain vinegar and maybe a 1/2 cup in a 5 gallon bucket.

Marcia

[klen11]

A vinegar and water solution before glazing your piece would greatly reduce the chances of spots like this. The acid in the vinegar will counteract the silicate and any oils on the piece.

[Mossyrock]

I have been working with majolica for several years and haven't had a problem with shivering on pieces created with the clay/glaze combination I use now. I use the LG-11 (although I usually brush it on straight out of the container, but if I dip it, I dilute it) and Highwater Clay's Stans Red clay. I've taken several Linda Arbuckle workshops and we used Stans Red there also. (BTW, Linda has a new DVD coming out soon.) However, I did have shivering problems with another base glaze I used on a white earthenware clay.....the shivering happened on any part of the piece that had an edge or curve. The flatter surfaces did not shiver. Good luck.....it's a fun process.