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Member Since 04 Oct 2011
Offline Last Active May 19 2017 04:04 PM

#124072 Kiln Not Firing To Temperature?

Posted by neilestrick on 20 March 2017 - 04:29 PM

Many 120 volt kilns are underpowered, and yours is only a cone 6 kiln so it's even more underpowered than a cone 10 version. At a cone 6 rating it really shouldn't be fired higher than cone 3. They need everything working properly in order for them to function correctly. At 8.8 ohms your elements are 10% off from the factory original, which is exactly the amount of wear when replacement is recommended. Assuming everything else it working properly (thermocouple, relays, etc) then it's probably the elements causing the problem.

#124046 Colemanite

Posted by neilestrick on 19 March 2017 - 07:05 PM

Test it out and see what you think. It may or may not be a problem. If needed, reformulate for whatever you have access to, be it Gerstley or Frit. Frits do not settle badly if you have a well formulated glaze with enough clay to keep it suspended. The problem is that a lot of old glaze recipes relied on Gerstley to keep the glaze suspended, which it does very well. So if you substitute a frit in those cases then you can have suspension problems.

#123922 Deflocculate, Or Toss It And Start Over?

Posted by neilestrick on 17 March 2017 - 10:14 AM

It is extremely rare that you would need to deflocculate a glaze. Usually if it's too thick you just need to add water, which seems to be the case here since they have sat around for a long time. If they settle out too quickly or too hard, then you need to flocculate with epsom salts.

#123789 Tea Pots

Posted by neilestrick on 15 March 2017 - 11:17 AM

The holes should work fine if you're using a long leaf loose tea, which most North Americans don't. I was taught to glaze a teapot with a built in strainer by lining the interior, and before the glaze sets up, blow the excess glaze sharply back down the spout so the holes are all clear. It's much less hassle than messing around clearing the holes with a brush/pipe cleaner/whatever, or getting them all wet beforehand.
All of that said, one large hole works just ducky.


In my experience, with small holes the glaze will set up and plug them before it can be blown out, especially with porcelain which takes in water quickly. And with runny glazes like I use the holes will fill up during the firing, so a thin layer of glaze is necessary, which wetting the holes before glazing accomplishes. It only takes a few seconds to wet them with a floppy brush.

#123774 Tea Pots

Posted by neilestrick on 15 March 2017 - 09:31 AM

To keep small holes from filling in with glaze, wet the holes with a brush before glazing. Because the clay is already saturated it won't take in very much glaze. Immediately after dipping the glaze, blow through the spout to clean out the holes.

#123735 Can Unglazed Pieces Touch In Cone 6 Firing?

Posted by neilestrick on 14 March 2017 - 10:13 AM

There are no stupid questions.


What is different about porcelain that makes it stick together when fired to ^6?  Can it touch during the bisque?  Would unglazed stoneware stick together if fired to ^6? 


I was very surprised to learn this.  Thank you again for your experience and expertise.


Porcelain gets very close to its melting point, therefore pieces stick. Think molten glass. Stoneware not as much, but still sticky to some degree. In a bisque it's not a problem because the clay doesn't get anywhere near its melting point. You could stack raw pieces in a cone 6 firing, but you would need to do some alumina wax wherever they touch, and they're much more likely to warp if you stack them.

#123726 Can Unglazed Pieces Touch In Cone 6 Firing?

Posted by neilestrick on 14 March 2017 - 08:10 AM

No, especially with porcelain.

#123715 That Time Is Approaching... How Hard Is It To Change Elements On An Olympic K...

Posted by neilestrick on 13 March 2017 - 09:54 PM

I always unstack kilns when I have to do pins. It's a major back saver. On a 3 ring kiln you can't tell what you're doing at the bottom unless you unstack it.


It's difficult to over-crimp, and you'll know if it's not crimped tight enough.


Flip your floor if it needs it.


Put the pins into fresh brick or they won't hold.


The bolt cutters will work great.


I take lots of pictures, too, when I get into wiring configurations I'm not familiar with.

#123692 New Kiln Wash Application

Posted by neilestrick on 13 March 2017 - 05:13 PM

If your stoneware fires really tight then it can stick some, too. Alumina in your wax is a good solution if you don't want to wash the shelves.

#123655 How Much Paper Burnout Is Ok?

Posted by neilestrick on 12 March 2017 - 10:16 PM

First, burning duct tape is not a good thing. It's plastic, so the fumes are not going to be nice. As for the volume of paper, the vent won't be able to handle it. You won't necessarily do any harm to the kiln or vent, but you're going to have a lot of smoke coming out of the kiln. Downdraft vents just aren't made to handle that kind of burning out. I've had calls from more than one school who set off the smoke alarms trying to burn out a lot of newspaper. When using newspaper forms, they should be loosely packed, using as little paper as possible so that the paper can compress as the pieces dry and shirnk, and you should remove as much as possible before firing. I would try to figure out a way to open up the pieces and remove the paper, or figure out a way to vent the room when the kilns starts smoking.

#123632 Speckled Glazes

Posted by neilestrick on 12 March 2017 - 01:43 PM

You could try a granular manganese or iron, but they may bleed out and/or discolor the white. It would be easier to use a speckled clay body with any white glaze.

#123583 Should You Glaze The Air Shaft Of A Clay Pipe

Posted by neilestrick on 11 March 2017 - 11:35 AM

With vitrified clay the alcohol cleaning shouldn't be a problem. I would think that even with porous clay the alcohol would evaporate out. Keep your clay under 2% absorption and you should be fine without glaze. Wood pipes aren't sealed on the inside, are they?

#123581 Making Oven Safe Work..

Posted by neilestrick on 11 March 2017 - 11:05 AM

Most clay suppliers will be able to recommend which of their clay bodies do well in the oven. In general, stoneware bodies do better. Porcelain does not do well. Ultimately you'll have to run some tests. It is also recommended that you do not preheat the oven when using hand made work in the oven, as it lessens the thermal shock.

#123576 Should You Glaze The Air Shaft Of A Clay Pipe

Posted by neilestrick on 11 March 2017 - 09:13 AM

I think that from a hygiene standpoint it would be good to have the air shaft glazed, especially if the clay isn't vitrified. Historically they probably weren't glazed, though.

#123531 Skutt 818 With Extension Ring

Posted by neilestrick on 10 March 2017 - 11:18 AM

Hi Niel, would a 6-50 installed last year likely be able to handle that? Its a dedicated receptacle right by breaker box on a 50 amp breaker and I have been running a skutt 1027 on it.


Yes, a 6-50 will work on that kiln.