Microwave Kiln Observations

Today I fired the man in the moon doll head.  The approx thickness at the mid/thickest point is just over an inch.

It fired slightly longer than a much thinner piece of clay, but not significantly.  When removed, I checked and it had cold spots.  (Or spots not as red as others)  I let the piece cool gradually to avoid shocking the clay.

When completely cooled I turned it over and noted that the bottom of it was almost raw clay and had micro cracks in it.  Thinner than hairline and almost unnoticable.  The microkiln does have its limitations.

I believe that if the piece had of been upright (instead of laying on one side it would have heated more evenly and probably would not have had the cracks.

On a second firing, the cracks become more noticeable.

 

UPDATE:  I just found out that fixing little non structural cracks is extremely easy.  The solution is to fire some of the same clay along side of it as dust, and then you can mix an epoxy with the ceramic dust and essentially spackle the cracks

2 comments

  1. I’m going to try that technique of spackling cracks. But what I am wondering is …
    if you do this in the bisque firing (the first firing) wouldn’t the epoxy burn out on the second glaze firing?
    I guess it can only be done afterwards? Or is this an epoxy that can be fired?

    • I dont know if i am going to do a second firing on the head just yet. Being that it is a doll head a glaze may not be neccacary. But again, this is my first foray into ceramics. What has been your experience? And for things which need the whole surface covered, how do you prop it up so that you can glaze the whole thing in one shot

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