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jolieo

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So just want to make sure I kind of have it straight:

( Guinea I WILL read the directions before I start)

I just feel confused.

So I am going to kiln was my shelves on one side only, and the floor of my kiln. I am going to fire to^018 - and again to ^05 empty to condition the kiln.

I am going to make stuff , and then bisque fire. Then I am going to underglaze then fire to the mature ^ rate of the clay. I will leave the kiln vented for the first 3 ramps and then shut it for the final ramp , hold and cool down.I can go to one ^ less and as long as I watch the free standing cones and do not overfire.i could have put glaze over the under glaze or I could do it in another firing. I can put China paints lusters etc low fire on over and fire them low. I can slow cool to improve some glazes or crystallization ( which I don't have to worry about with velvet underglazes.) I don't open the kiln until it is pretty much cold . If I hear cracking noises the glaze fit is bad.

Green ware can be fired w glazes up to maturity , but ?? Maybe a beginner shouldn't ?

Where I am confused: so what if I fire up to maturity and try to put a lower ^ glaze on? Is there such a thing?or really where does maturity come into play - once fired to that extent can it take glaze all?

I am aware that I am generalizing in a pretty extensive and quirky subject. I am just trying to plan out my strategy. I Like matt surfaces, maybe semi gloss .

Ok please you can link me if that helps , thanks Jolie

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You really only put glaze onto your bisq ware, it's still thirsty. When fired to maturation the body closes up and no longer takes glaze very well. When you get a few dozen successful firings under your belt you will have the confidence and understanding to begin to experiment. keep it simple, keep it easy. Get some books on firing methodology and put in your practical application time and you will discover most of what you need, attend some workshops and community firing (anagama possibly). Good luck, have fun

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I have done plenty of firings, and with a few exceptions, I don't glaze greenware.  There are just too many issues with doing so.  If something explodes, you have bits of glazed ceramic sticking to everything.  You have to be very careful glazing the fragile greenware as well.  

Even the production potters here, double fire.

 

From what I've seen, factories tend to single fire, because it allows them to keep their costs low, with the large scale they deal with.  For smaller potters, it's not worth the headaches.

 

As John said, glazing vitrified clay is difficult.  Why not just approach it the standard way, and bisque low, glaze with the appropriate glaze for your clay type, then refire to maturity?

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So I am going to kiln wash my shelves on one side only, and the floor of my kiln.

Kiln wash one side of the shelves – yes; there is no need to put kiln wash on the floor of your kiln. Instead, put ½†or 1†posts on the floor and place a shelf that has been kiln washed on the posts. A raised floor is better for your wares than placing directly on the floor.

I am going to fire to^018 - and again to ^05 empty to condition the kiln.

If the kiln is new and unused, then a conditioning firing is recommended. Or, some will do a conditioning firing if you have changed all of your elements – the firing burns any protective coatings on the element wires. If a conditioning firing is needed, cone 05 should be sufficient. If you do a conditioning firing, stack your shelves and kiln posts in the kiln as if they had wares on them (spaced evenly in the kiln) so that there is some mass to heat up; it will help speed up the firing vs. firing a completely empty kiln.

I am going to make stuff , and then bisque fire.

Yep.

Then I am going to underglaze then fire to the mature ^ rate of the clay.

Underglaze can be applied at either the greenware or bisque stages. It is mostly a matter of personal preference.

I will leave the kiln vented for the first 3 ramps and then shut it for the final ramp, hold and cool down.

I start my kiln vent when the kiln is turned on and turn it off when I empty the kiln after cooling. Others prefer to turn the kiln vent off after peak temperature and let the kiln cool without the aid of the vent. Again, it is a matter of personal preference. The vent helps draw air through the kiln as it is firing; this can make some colors brighter in an oxidation environment. Turning the kiln vent off before reaching final temperature (e.g., the final ramp) could – repeat, could – affect color. But, you will need to try both ways – leaving the vent on and turning it off – to see how it might affect your particular glazes.

I can go to one ^ less and as long as I watch the free standing cones and do not overfire.

If you are using witness cones for glaze firing, you should have three cones. For a cone 6 firing, you would want cones 5, 6, and 7. And you will want them on the bottom, middle, and top of the kiln (hopefully there are peep holes for all three levels).

I could have put glaze over the under glaze or I could do it in another firing.

It sounds like you are thinking of putting underglaze on bisque ware, then refiring with underglaze, followed by a third glaze firing. If you take that approach, your second fire for the underglaze should only be to bisque temperatures. Then apply the glaze and fire to glaze maturity. But, if you let the underglaze dry, you can apply the glaze over it and fire to glaze maturity and save yourself the extra step and cost of firing and wear/tear on your kiln. I have done the three fire approach – but the items were somewhat exception in that another artist did artwork on the bisque ware and I wanted to avoid any running, smudging by applying glaze (dip, not brushed on). The second batch of that series was underglazed and glazed in one firing – with no problems. Again, personal preference is the key driver.

I can put China paints lusters etc low fire on over and fire them low.

Yes. China paints and lusters are applied over glaze fired wares and then fired at a lower temperature to affix them to the glazed surface. Some artists do successive application of China paints and successive firings, each one lower than the previous one. There are good books available that explain the process.

I can slow cool to improve some glazes or crystallization (which I don't have to worry about with velvet underglazes.)

Yes, slow cooling can improve some glazes and promote crystal formation. Slow cooling will not affect velvet underglazes.

I don't open the kiln until it is pretty much cold. If I hear cracking noises the glaze fit is bad.

When to open is a matter of some personal preference. Some clay bodies are more sensitive to thermal shock – cooler air rushing into an opened kiln. Check the forums for other threads that have long discussions of pros/cons. Pinging or cracking noises can be an indication of bad glaze fit or opening the kiln too soon.

Green ware can be fired w glazes up to maturity, but ?? Maybe a beginner shouldn't?

Some potters once-fire, e.g., they apply glazes to greenware and then fire them only once. Generally, you need a slower firing schedule and you may need to adjust your glazes for once-firing. Once firing can be done in any type of kiln or atmosphere (oxidation/reduction). Takes some practice, though, to get it to work for your clay body and glazes. I would find someone who does once firing and learn from them before trying it on my own.

Where I am confused: so what if I fire up to maturity and try to put a lower ^ glaze on? Is there such a thing?

Glazes are formulated to melt at certain temperatures. Obviously, a lower cone glaze will melt more/be more running if fired above its intended temperature. Similarly, a higher cone glaze will not melt completely at a lower temperature. From a functional standpoint, glazes should be durable and fit well. Overfiring or underfiring affects durability and fit. So you try to match them up.

Some potters (see the wonder teapots of Fong Choo) apply lower cone glazes over other glazes to achieve a look or aesthetic – generally, these are limited to the outsides of functional wares. So, it can be done. But it takes a good deal of experimentation to see how they interact and work with a particular clay body.

or really where does maturity come into play - once fired to that extent can it take glaze all?

A clay body fired to maturity has a low rate of absorbency. Trying to apply a glaze on top of that surface is difficult and requires extraordinary steps, e.g., preheating the piece and then dipping in glaze. Clay fired to maturity is not as able to absorb the water out of the glaze, leaving only the glaze behind. That is why you bisque to a lower temperature.

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Well, bciskepottery (and the precedent writers too) said it all.

 

I want to comment on the once-firing (glazing and firing greenware). I once-fire very often. I've learned it from Steven Hill. I appy the glaze with an atomizer and let dry the layers before applying the next. No dunking the piece in glaze!, no painting on the glaze!, that would soak the green piece too much.

I fire very very slow, approx 16-18 hours for cone 6, in an electric kiln. More slow at the beginning then at the end. Always great results, never exploded pieces.

 

Jolieo: If you never fired your kiln yet, start with bisque firings, and then glaze firings, the normal way. Until you are more experienced. But then, I would strongly recommend: experiment!!

 

There is a wonderful DVD on the market of Steven Hill about once-firing. You can buy or download it from the bookstore here:

 

http://ceramicartsdaily.org/bookstore/the-surface-techniques-of-steven-hill/

 

The main issue is: have fun in doing what you're doing! Be courageous.

 

Evelyne

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there is one other thing you might want to know.  if you apply your velvet underglaze on greenware with a brush, you will be able to tell if the color has been evenly applied after you bisque fire the piece by dipping it into water and looking for thin spots or brush strokes.  putting velvets on greenware is a common practice.  waiting until it is bisqued only wastes a firing without gaining anything.

 

please get some basic old timey (1975-1979) basic books from your local library and learn all about what you are trying to do.  

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I want to do it all is the problem! Lol, really do want try everything, so my brain doesn't stop poking at every thing I' ve seen, every glaze , every clay. Which is fine , except I am a process person. I have read a lot of books , but never done it myself . There is no community kiln, or workshop here. I have made stuff and other people have fired it, but those shops are gone.

So I am constantly bringing myself down to earth by reciting all that has to be done.

The only thing I am not into right this second is making my own glazes. I know that that is too much to process at first, plus the humidity here pretty much eats everything, very hard to seal it out, a lot of stuff turns to stone, and I do not feel like dealing with that yet. Thanks again jolie

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