[Ray Bright]

My 1st firing has produced a strange effect: the clear glaze on the edges of my pieces are smooth, but in the center they are bumpy, seem not totally fixed to the substrate, covered with a sort of orange peel. The glaze is still clear, not all pieces are like this, and I think I may have laid on way too much glaze in my zeal to make very shinny objects.

Humm?

[neilestrick]

Possibly too thick, underfired, or crawling. Is this a glaze you've used before?

[Ray Bright]

neilestrick, on 10 October 2012 - 09:53 AM, said:

Possibly too thick, underfired, or crawling. Is this a glaze you've used before?

No. AMACO LG-10. I think I laid it on too thick. Within the same piece, the glaze is good & bumpy. So it fired properly. Where it's bumpy, is where I glopped on a big dab of glaze (3 times) which I then spread out toward the edges, which are just fine.

Three days ago I fired a kiln for the first time in my life. I'm making it up as I go along, knowing nothing. I'm a retired movie producer whose fallen in love with the ceramic process. (my father was bricklayer). I'm very used to winging it, with far more pressure than this calls for. But I'm in it to make the thing I want to make as good as it can be made.

Thanks,

Ray

[neilestrick]

LG-10 is typically very consistent, so you must have applied it too thickly.

[Ray Bright]

neilestrick, on 11 October 2012 - 11:16 AM, said:

LG-10 is typically very consistent, so you must have applied it too thickly.

I really laid it on. Next test this Friday, think thin.

[neilestrick]

Although the labels usually say 3 coats, you can often get by with 2 flowing coats, brushed on in opposite directions. Depends on how thick they mixed it.

[Lucille Oka]

To what cone or temperature did you fire this LG-10 glazed ware?

[ayjay]

neilestrick, on 11 October 2012 - 06:25 PM, said:

Although the labels usually say 3 coats, you can often get by with 2 flowing coats, brushed on in opposite directions. Depends on how thick they mixed it.

The brush can make a difference too, I find a soft fan brush is good for glazes designed to be brushed on but I use something that holds a lot more glaze if I'm brushing on a dipping glaze.

[Ray Bright]

Lucille Oka, on 12 October 2012 - 12:35 AM, said:

To what cone or temperature did you fire this LG-10 glazed ware?

Fired to cone 05. Using very old Skutt with bar type cone in Kiln sitter. Some things on the most problematic shelf came out perfect, but these had much more vertical surface. The orange peeling ones were 95% flat, and I think I put so much glaze on it pooled in the middle and couldn't finish properly. This was my 1st firing/test of this system, will no much more soon. Will use only 2 coats with same application method.

R

[Lucille Oka]

I am trying to understand the term you used 'orange peel'. If there are a lot of 'teeny tiny pits' (orange peel) this is a bit of a thin application and an underfire. If you see a lot of small bubbles under the glaze surface and those bubbles make the glaze look a bit cloudy then yes you applied too much glaze.