Help -- newbie...

fire to 05/06 first, add glaze, fire again to your cone 6.

it is possible to single fire, adding glaze at the dry clay stage. ~ but you'll have to test your self to make sure it works the way you want.

see ya

steve

Usually you bisque to 06-05, apply glaze, then glaze fire to cone 6. You can single fire only if the glazes tolerate it, which can only be learned by trying. Some glazes will blister in single fire--usually gloss glazes that are affected by gases which are more burnt out from the double firing system. It's best for beginners to start with the bisque fire--it makes the pots much less fragile for glazing. Brad Sondahl

To add to what others have said about single-fire techniques, note that the biggest problem is that if you try to apply glaze to bone-dry greenware, the clay may absorb too much water and expand, producing serious cracks. Usually these cracks will be obvious when the glaze dries, but it's also possible that they will be internal and will cause the piece to be weak after firing.

Another problem is that while you are applying the glaze, and the piece absorbs water, it may become too weak to handle. Glaze application by dipping is a big problem because of this. Many folks who single-fire thus either apply glaze by spraying the bone-dry ware (which puts less water into the piece) OR by applying glaze to the piece at the leather-hard stage. In that case, you may have to fiddle with your glaze formula to get best results.

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

Steve, Brad, Bob: Thanks! This is exactly what I need to know.

Fred

I'm making garden lanterns -- both electric and candle. Curently, I'm experimenting with different clays but leaning toward stoneware that matures at cone 6. I'd like to go for higher-fired clays but the only kiln I currently have access to is a cone 8 max electric, so it's all oxidation only for now. I expect to glaze more on the primitive side, probably not glazing the entire piece. Maybe tops only or a partial dip for the bottoms.

I'm really new at this. Learning a lot!

Thanks,

Fred

Cone 6 should do fine for a garden lantern (though in harsh climates you might want to store it where it will stay dry). Cone 6 electric (oxidation) can give you just as interesting a look as cone 10 reduction and it saves a lot on energy consumption.

Thanks for the great references! There's plenty here to keep me occupied for awhile.

Quick question: I'm leaning toward jumping right into mixing my own glazes, and recently read much on the subject. Is this a mistake? Should I stay with commercial glazes at first? I'd really rather mix my own. Thanks for your thoughts.

Fred

I'd buy a couple of glazes for a start; just to get the hang of glaze firing. Once you begin to get a feel for it then you could experiment with one or two home mixed ones to fire alongside the bought ones.

Make haste slowly and learn thoroughly!

Steve Bath UK

In article , Fred writes

a general guidline at work for having motivated employees is to find out what they like to do, and give them a job doing it.

if you're motivated to dive into glazes, by all means do it!

start with a simple one or two & take it from there.

one quick easy glaze is get some cone 6 or 10 porcelain slip, add mason stain. ~ not a glase per sey but fast color!

i mixed my 1st batch of ash glaze as a raw beginer. got cool results, did it all differently years later but still had fun.

see ya

steve

One of the first things I learned was mixing glazes and I consider it a very rewarding part of the process. I would recommend Mastering Cone 6 Glazes (one of the links I gave). KISS (keep it simple ____) though. I would not invest the money in the rutile and cobalt for glazes to begin with (spearmint and bone both take a lot of rutile and it is costly - cobalt is now $40/lb I think). I say this knowing that they are two of my favorite ingredients. They are just expensive and not what you want to be learning with. I would get enough to use for decorating (mix a small amount with the glaze you find you like and use it like a paint over the glaze). Also get some copper carbonate and some good iron oxide. Your glaze test batches should be at least 200 milligrams (many people use 100 and I think that is just too small - a very small error gets exaggerated).

Good luck!

In message , Fred writes

Hi Fred,

I'm just a beginner too so my advice on pottery matters is far from expert. But over in the quilting newsgroup we have a saying: "there are no quilt police". In other words - you want to do it? Go for it. What's the worst that can happen?

So, are there any pot police? Can you get arrested for mixing your own glazes without a license?

Actually I know that's a smidge flippant - I love the look of salt glazes and I was disappointed to learn that if I fling salt in my regular kiln it will be permanently ruined for normal firing. And some of the ingredients of glazes are very toxic, so I'd make sure I understood thoroughly what precautions to take before I started messing with compounds of arsenic or antimony for example. I'd recommend you start out with plenty of reading and asking questions but if you feel moved to mix your own glazes, then you should do it, for sure.

i was bored with the idea of reading up on glazes before just doing it. so when someone said "ash glazes, just add water". ~ i did just that, but looked cool & i learned how to use it. they ran like crazy & this other guy said "add 50% porcelain". that settled down the runs. further talks someone said "throw a little mason stain in". BOOM! i had a cool glaze!

so there - you read enough, go dive in!

~ now, i kept no notes, measured nothing, and can't repeat that really nice green ash glaze i had until the bucket went empty!

see ya

steve

In article , steve snipped-for-privacy@aol.com writes

If I had a pound for every time I've heard that comment I'd be a very wealthy man now!!!!!

Be warned

Steve

In message , Steve Mills writes

But Steve, I keep notes, I measure everything, and yet my nice green barium glaze turned out blue when I made up a second batch.

Another lurking variable.

bingo - hense steve mill's comment....

see ya

steve

Are you using the exact same materials as when you mixed up the first batch? A slight variation in the chemistry can influence whether your copper goes to green or to turquoise blue in oxidation firing. Is there any K2O in your formula? Also firing rate will influence the color you are getting. Celedon glazes (iron oxide) vary a great deal in color (reduction influences the chemistry of the final product) - sorry, tangent.

Barium does make copper go blue.... Could you have had less Barium in the previous glaze?

In article , DKat writes

Jake, to follow on with Donna's comments; did any of the materials you used come from a different source than the previous ones? I know from personal (and commercial) experience that performance variation between one supplier and another is a very real problem for the user. That is why most Ceramic Supply Shops only buy each material from only one known source for that material. Consistency is our biggest watchword.

Steve Bath UK Retired ceramic supplier, now back to making pots (hooray)!

In message , Stephen Mills writes

Thanks to Donna and Steve for suggestions. I cannot remember the sources of materials for the different batches of barium green: the recipe is in my notebook as 'Lewis', but I didn't record its origin, dammit. I do recall that the original recipe specified strontium carbonate, but I had converted this to use barium carbonate.

I am now going to test some modifications to the glaze, in an attempt to recapture the original delicate green.