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Alina Albu

Member Since 27 Jun 2012
Offline Last Active May 27 2013 02:56 AM
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Posts I've Made

In Topic: Firing times

18 May 2013 - 04:24 AM


Yes, the time to slow down is as you get within a hundred degrees or so of the max temp and then during the cool down.

Jim


This is key- depending on what type of an effect you want from your glaze. A glaze that yields a complex, matte or crystalline surface with a slow cool-down can be translucent or even transparent if the kiln is just switched off at its peak.

Either may be fine... but be aware of what you want.


Hi Kohaku,
At the moment I am after glossy glazes, but will bear that in mind when trying something different.

Like your signature line. And "All that glitters is not gold". (no, it´s my glossy glaze! hehe)

In Topic: Firing times

18 May 2013 - 04:20 AM

You can fire as fast as your furniture can take really. The thing that folks have eluded to is that many glazes look better with some time near high points to mature. That is the time they are very near end point in a cone or temperature setting. Most glazes will look better if allowed to have a slower time around maturing temperature-that is slow down near the end so they can mature slowly. This way the crystals can mature and the glaze matrix will look better. The cool down also needs to be slower so the glaze can cool slowly from the top end. This will make your glazes look better..
If you want to really find out how this works you can try what I did in 1972 fired my small gas kiln to cone 10 then unbrick the door as soon as it turns off. This reveals all glaze /body flaws such as shivering and dunting and can lead to kiln shelve loss. You only need to do this once to learn the down side to quick cooling.
Since then I was nicknamed the Cooler King until Steve MaQueen got the name in the great Escape.
I like a two day cool now unless its a time squeeze.
Its good to test the limits in ceramics to know what they truly are as many limits taught in schools are not really where you may think.
Mark


Hi Mark,

I am after glossy glazes anyway, don´t do any matte or crystalline. At least not for now. My issue was trying to get a slow cooling period down to 800ºC, and that was not possible on my kiln as it only has 4 phases, of which the first three were taken with the ramping up and soaking. I have to fire overnight and I am not always there to fiddle with the controls. So, what I am going to do from now on, I´ll try and get to top temp in one phase, soak in phase two, cool slowly to 800ºC in phase three, and that gives me another phase for cooling off to the end. Yep, that might work. Thanks
Alina

In Topic: Glaze percentages

17 May 2013 - 04:42 PM

Also worth asking... Cobalt Oxide or Cobalt Carbonate? One has approximately double the actual cobalt basic oxide of the other, so will affect the intensity of the blue you get.

An online glaze simulator tells me this is a pretty high-fire glaze (http://www.glazesimu...m/recWizard.php).... Just curious, what are you firing this at?


Hi mregecko

Oxide.

I am not familiar with cones, I fire at 1255ºC with a 20 min soak and it works beautifully for me. Tried the glazesimulator, don't agree with above cone ten - is there anything above cone ten?! This is a glaze that has been used by other potters I know for this range of temp.

Sometimes these things are too clever for their own good.(:-)

Have a great weekend!

In Topic: Glaze percentages

17 May 2013 - 01:27 PM

Aaaaah, now that makes sense - Thank you Marcia. I must say I did not think that about Bentonite. We live and learn.

Jim and TJR - I have used the glaze before, it was at another potter's studio, she dictated the recipe to me (hence my thinking I made a mistake). It is a nice kind of sky blue glaze, glossy, I like it on all bodies ~but will have to test it on my new black clay.

However, it does tend to "spit" a teeny little bit, not quite sure why. My guess is that it happened when I laid it on a bit thick. Anyway, thanks again. Problem solved.

Alina

In Topic: Firing times

17 May 2013 - 01:16 PM

This is great, thanks everybody! I guess I'll go for it.

Marcia, I will only have a few hours to let the glaze dry. Hope that will be enough.