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Member Since 04 Oct 2011
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#74556 Does Fading Always Mean A Glaze Isn't Food Safe?

Posted by neilestrick on 31 January 2015 - 03:21 PM

You'll see a lot of matte glazes out there in the world that are simply under-fired glossy glazes. It's not a good way to make a matte, because it means you are not getting good glass formation because it's not going hot enough. These types of matte glazes are not usually very durable, and can leach because the materials are not locked up in the glass.


The better way to make a matte glaze is through the use of materials that promote matteness, such as magnesium. The glaze can be fully matured (runny even), with good glass formation, and still be matte. This type of glaze is much more durable, and more likely to be food safe.


The big problem is that there are a lot of folks out there who don't care to do their homework before using a glaze. They assume that if someone else was using the glaze, then it's good to go. A good number of the glaze recipes I find online I would never use without doing some reformulation. It's easy to make a pretty glaze. It take a little more work to make a durable glaze.

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#74482 Studio With No Main Water Or Mains Drainage....ideas ..can It Be Done ?

Posted by neilestrick on 30 January 2015 - 03:11 PM

When I had my garage studio, I worked out of 5 gallon buckets for water. If you're organized, you really don't ever need to wash anything down the sink.

#74460 Ruined Kiln Shelves - Any Uses For Them?

Posted by neilestrick on 30 January 2015 - 09:38 AM

I keep a bucket of broken shelf shards to use as shims when I need a shelf to be just a tad taller. I also use them under pots that I think may run.

#74457 Venturi Vs Forced Air

Posted by neilestrick on 30 January 2015 - 09:05 AM

Evenness has nothing to do with the type of burners. It has everything to do with kiln design. Either type of burner can fire a kiln evenly if the kiln is designed and built properly.


I prefer power burners because I can get away with having only one or two burners on a kiln, rather than 6 or 8, and I can build my own. I also think power burners are safer in that you have a dedicated flame sensor/thermocouple and pilot/ignition system for each burner, rather than relying on a pilot ring which may or may not be lighting every burner. Kilns with power burners do not need a chimney any taller than the kiln, so they easier to build. Take a look at all the threads here on the forum about kiln construction problems and they all use venturi burners and are struggling with gas pressure, burner quantity and flue height. With power burners, you can adjust the orifice size and blower size easily.


I never had any trouble bisque firing in my gas kiln. I used to bisque 50 pound planters in it without blowing them up. The key is to have a strong enough pilot that it can preheat the kiln to at least 200 degrees overnight, and you must have a blower control to slow down the blower speed so that the burner can be run at low pressure.

#74390 Kiln Dismantle ?

Posted by neilestrick on 29 January 2015 - 10:30 AM

Buy it for the bricks and furniture and build what you want. Build your own power burners.

#74229 Dishwasher Safe

Posted by neilestrick on 27 January 2015 - 06:21 PM

Vitrified clays would be best. As for glazes, some will etch out over time due to the harsh soaps, but it depends on the glaze and the type of soap being used. Shiny pots can lose a little shine, but that happens with commercial dishes, too. I consider everything I make to be dishwasher safe.  And I wouldn't be able to sell half as many if I told people they had to be hand washed.

#73808 Difference In Digital And Manual Kilns

Posted by neilestrick on 21 January 2015 - 06:30 PM

My kiln is actually new. It's an L&L digital.  I've had a Duncan for about 15 years before it quit, it was manual.   I was just confused about the cone thing.  Cause the clay says 4-6 cone but Standard recommends to fire at 5.  I usually fire most things at 5 for glaze recommendations.  But on occasion,  I'll make something that is not glazed and want to fire higher to get the darker color.


Cone 5 with a 10 minute hold will get you to 5 1/2. With a manual kiln there's no cone 5 1/2 to put in the sitter, so you have to fire until visual cone 6 is bent to 3 o'clock, which equals about 5 1/2. Visual (large) cones start at about 1 o'clock, and you've reached the cone when they are bent all the way to the shelf, or 6 o'clock.

#73696 Should This Glaze Fire Out Glossy?

Posted by neilestrick on 20 January 2015 - 03:09 PM

I cool at 175F/hr from cone 6 down to 1550F, because some of my glossy glazes look better with a little more time at the high end. Most people who slow cool will let it cool naturally to around 1950F, then slow cool down to 1450-1550F at 150-200F/hr, where matte glazes will develop.

#73684 Should This Glaze Fire Out Glossy?

Posted by neilestrick on 20 January 2015 - 12:24 PM

Try adding a cooling cycle to your firing if you're not already. It should help to knock down the glossiness. It could be that the firings in which it came out less glossy were fuller loads, and therefore cooled slower. Some glazes are very touchy about cooling rates. I used to have one that was high gloss in a fast cool, matte in a slow cool.

#73532 Why Do The Fluxing Molecules Only Have One Oxygen Atom

Posted by neilestrick on 17 January 2015 - 03:49 PM

Also research 'eutectic'.

#73472 Creating A Ice White Porcelain Clay Body

Posted by neilestrick on 16 January 2015 - 05:46 PM

Working in oxidation will make this a little easier for you, since minor impurities won't have as big an impact as in reduction.


If you want 'true' porcelain, avoid ball clay altogether. But if you prefer the feel of a white stoneware, then go for it.


VeeGum T is an excellent plasiticizer for porcelain, and won't affect the color. Make sure you blunge it in water first before adding it to the mix.


In general, the glassier the porcelain, the whiter it will be. However the glassier it gets, the more problems it will have. Too glassy and it will slump or warp in the firing. It can also have plasticity problems, where attachments tend to pull away or pop off.


Personally, I'm more concerned with the workability of the clay body rather than how white and glassy it is, since I cover everything with glazes anyway. Most good commercial porcelains are quite white and acceptable to me. I use Standard 365 cone 6 grolleg porcelain, but they also make a cone 10 version. It is not as glassy as some porcelains I have used in the past, but I have virtually no warping and cracking problems.


Why do you want to make your own? Have you not been able to find an acceptable clay body from commercial suppliers?

#73232 Holding Temp

Posted by neilestrick on 13 January 2015 - 03:40 PM

Stuff burns out of the glaze during firing, so you want to leave the top peep open to vent it.

#73218 Kiln Dismantle ?

Posted by neilestrick on 13 January 2015 - 09:57 AM

Lots of fiber on there. You'll need to wear a mask the whole time. Looks like homemade pipe burners. I wouldn't mess with those, just build a couple of power burners. Are there any safety systems? I don't see any pilots.


Still wouldn't touch it. Maybe buy the bricks, but forget the rest. 

#73217 Deflocculated Wax Resist?

Posted by neilestrick on 13 January 2015 - 09:55 AM

I've been adding food coloring to my wax for years, without this happening. Maybe check labels next time you're at the store and see if there's a difference between brands.

#73090 Anyone With Experience Firing An Olympic Updraft Kiln?

Posted by neilestrick on 08 January 2015 - 05:58 PM

I know a guy who fires all of his work in one of those, but it's a real struggle. As mentioned above, he has to put certain glazes in certain spots to account for the unevenness. You'd be better off converting an old electric by adding a downdraft flue. The old square Amaco models work well for that because they have a thick enough case that you can weld to it. They're super heavy and a bear to move, though. I did one for a friend 15 years ago and she's still using it. I welded a chimney to the back side and put a small burner on each side of the chimney. She fires to cone 10 and reduction cools in it.