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neilestrick

Member Since 04 Oct 2011
Offline Last Active Today, 04:55 PM
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Posts I've Made

In Topic: Drying a Mold Quickly: Home dehumidifier vs drying cabinet?

Today, 03:18 PM

Air flow and low humidity are better than heat for drying plaster. Use the dehumidifier and a fan.


In Topic: How About Toothpicks For Spike Supports + Other Questions

Today, 10:25 AM

Could you post a drawing of what you're trying to make? I really have no concept of how these spikes will be used. They may not need any support at all depending on how they're used.


In Topic: How High Did I Fire?

Yesterday, 05:54 PM

If your controller is that far off, then either the thermocouple is worn, or there's something wrong with the calibration, or both. Are you programming it to fire to a specific temperature, or to a specific cone? If you're firing to a temperature, then you have to figure out what that temperature is for your desired cone as it relates to the rate of climb. If your controller kiln can't keep up with the programmed rate of climb, then you won't hit the desired cone at the programmed temperature. If you can't trust the kiln or controller, then watch the cones. Guesstimating will only give you more bad firings. A controller is no good if it doesn't give you the results. Plus, when you change the thermocouple in the future, you'll have to start all over with your estimates.


In Topic: Using Wire Support To Make Spikes

Yesterday, 09:17 AM

The clays we use form making pots and such are called 'clay bodies'. Each is formulated for specific characteristics such as color, firing temperature, and texture. Porcelain is a clay body, just like stoneware or earthenware. They all contain different types of clays as well as binders (feldspar), silica, and grit (grog or sand). What sets porcelain apart from other clay bodies is that it's lower in clay and higher in feldspar and silica. So once it's fired, it's much glassier than stoneware or earthenware bodies. You can build with porcelain just like any other clay body, but it does require good technical skills as it is more likely to warp or crack than other bodies.

 

Cone 6 porcelain is still porcelain, it's just formulated to fire at a lower temperature. But can still be glassy and translucent just like cone 10 porcelain.

 

Wire stilts do not generally work very well at cone 6. The wires tend to soften and bend. So instead we just make sure the bottom of the foot is clean of glaze, and fire the pot sitting right on the shelf.

 

In general it's not a good idea to leave wires inside the clay, since the clay shrinks and the wire doesn't, which causes the clay to crack. I say just make the spikes and attach them to the form by scoring, just like any other attachment.


In Topic: How High Did I Fire?

16 December 2014 - 08:51 PM

If your kiln took an hour for the last 50 degrees, that's pretty slow. I'd check to see if your elements are worn, of if your kiln isn't rated for cone 6. At that slow a rate of climb, the temperature for cone 4 will be quite a bit lower than the slowest (108F) rate of climb shown on cone charts. Cones measure heat work, which is dependent on the rate of climb. You've got to watch the cones bend to know for sure.