Another firing:

[DONNZ]

They looked good out of the kiln. Cracked when heated with torch. Care was taken not to heat quickly. Poured two bars of lead and one of aluminum.
No flux used in dish or mold.

Stoked the kiln up to 1700º and held that for 4 hours. Hotter? As far as I can tell the fire brick did not fuse. I'll need to fine a substitute for the fire brick.

Have plenty of these to play with.

 

[DONNZ]

Organized notes, back on track. Kiln loaded.

Target temperature should be 1200c / 2192º.

Keeping notes organized will help.

Sorry Irons2, I muffed it up. (Make your own porcelain)

 

[Irons2]

Organized notes, back on track. Kiln loaded.

Target temperature should be 1200c / 2192º.

Keeping notes organized will help.

Sorry Irons2, I muffed it up. (Make your own porcelain)

No need to apologize. Try firing the ceramic at a much higher temperature (Cone 10 or greater if you are using an electric kiln) this will give it the temperature needed to begin fusing the ingredients and causing a crystal structure to grow (with Time) to give it more strength. 1200*C is a good target

Not an easy Hobby, is it?

 

[DONNZ]

Got that right. Waiting for the last 400° to drop.

Here's one for you: Cheep emergency fix or wow your friends.

Building a Pyrometer:

http://www.artmetal.com/brambush/forum/bramyak1/messages/611.html


And the chart:

milliamp-to-temperature chart (under "F")

http://www.pyromation.com/Search.aspx?cx=005719226341633012140:etrabskuw9s&cof=FORID:10&ie=UTF-8&q=milliamp-to-temperature+chart&sa=Search

 

[Irons2]

If you use enough thermocouples, you can make a useful amount of electricity.

 

[butcher]

:lol: maybe we could light an led with all of them different wires twisted together, heated by the electric kiln heck enough of these and we could ban the incandecent light bulb to save energy.

 

[DONNZ]

:lol: maybe we could light an led with all of them different wires twisted together, heated by the electric kiln heck enough of these and we could ban the incandecent light bulb to save energy.

Put them in the oven. When baking it may run the vent-a-hood light but not the vent motor.

 

[DONNZ]

When you said crystallize I sure this is not what you had in mine.

Max temperature of kiln is 2000°, it ran a little over that but showed no signs of overheating.

Everything still works, the heating element and probe, but I won't run again until I replace them, in 2013.

I think one of my dishes touched the heating element and then the probe. Bet that look like an induction coil. Not giving NoIdea's here.

Brick will need some minor repair. Ceramic fiber board did a good of catching the blob. Used it for a shelf, but under the shelf is another black blob.
Won't be able to separate the blob from the board.

I might frame this and call it art.

 

[Irons2]

Needs some Lomotil.
Time to redo the mix. That one isn't going to hack it. :mrgreen:

I always do a test firing with any new mix to see how it reacts. I just cast it into a plastic container lid to get an idea on shrinkage and cracking, then take it out of the lid and fire it.

 

[DONNZ]

Needs some Lomotil.
Time to redo the mix. That one isn't going to hack it. :mrgreen:

I always do a test firing with any new mix to see how it reacts. I just cast it into a plastic container lid to get an idea on shrinkage and cracking, then take it out of the lid and fire it.

Only 6 dish were lost. The mix has firebrick, fire clay and small amount of...............X
Made three dish with X. Three dish with 2xX. All about half size for testing.
One dish survived but in cased in that molten mass you see in the pic.

I'm sure it not the mix but somehow ran super hot inside the kiln. Like current running through the dish and caused it to superheat. Sounds good to me but really have no idea what happen in there.

" I think one of my dishes touched the heating element and then the probe." I can see where the dish was touching the heating element, a hot spot is visible. We can see where it was touching the probe in the pic.

 

[Irons2]

Try scraping the goop off of the element, otherwise it will eventually eat through the Nichrome.

Too much flux will cause the ceramic to liquify. You want just enough to fuse the particles together and form a crosslinked mesh of Mullite crystals to give it strength.

A good mix should easily take 1500*C

 

[DONNZ]

"Too much flux will cause the ceramic to liquify."

You lost me when you use the word "flux"

Flux in the mix?

 

[Irons2]

"Too much flux will cause the ceramic to liquify."

You lost me when you use the word "flux"

Flux in the mix?

Yes, fluxes, just like in Smelting, usually compounds containing Alkali Metals, Boron, Iron and various combinations. Something in your mix is acting as a flux, causing it to liquify at high temperature. A little flux is required. Too much will give you...the runs. I suspect the X part.

 

[DONNZ]

Cleaned kiln and ran a short test making sure it still works. So far so good.
Re-fired 4 pieces for 3 hours @ 1500ºF. This gives me a baseline for firing in a rapid fire kiln. I've used larger kiln's in the past, firing in a small kiln is a bit different.

Sneaking up on the time and temperature using this kiln would be the best approach.

That little dish is much closer to being fused. Very grainy the first firing.

Next week mixing up more X and 2X formula and try again.

Dang, I'm out of X and need more. Last trip to the hardware store I checked but they didn't have the same brand and I'd like to continue using the same brand in my experiment.

Not so helpful hint is it.

Gotta love a mystery.

 

[DONNZ]

X is graphite

When I get my energy back I'll share what I have.

Chest cold complements of grand kid.

 

[HAuCl4]

An idea would be to join a "pottery school" where the teacher can make porcelain. Learn that exactly, and all your current troubles will melt away. :lol:

 

[DONNZ]

One might think that would be the way to go. But when you pick their brain you fine making a dish or crucible is beyond their knowledge. They don't torch porcelain.