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neilestrick

Member Since 04 Oct 2011
Offline Last Active Today, 05:32 PM
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Posts I've Made

In Topic: Stacking Help For Reduction Gas Firing

Today, 04:54 PM

Each kiln is different, but if your kiln fires nicely, you can load it just about any way you want. The only thing I would avoid is putting very short shelves at the very bottom and getting too close to the walls. But I've never had a problem with appendages hanging out over the bag walls as far as kiln performance is concerned. I've had the good fortune to fire dependable gas kilns over the years, and have always stacked them as tight as possible, with less than 1/8" between pieces. If it's designed properly, there will be good air flow through the kiln even if the stack is very tight. You do not have to be all that concerned about flame path like you do with a wood burning kiln.

 

In a downdraft kiln, the bag wall is designed to force the flame upward before it is pulled down and out the flue. The height and tightness of the bag wall will depend on the kiln. For a new homemade kiln it will take a couple of firings to figure it out. If the top runs cold, the bag wall is built higher.


In Topic: Underglazes

Today, 09:02 AM

Speedball. Cheap and good.


In Topic: I Want Porcelain!

Today, 09:01 AM

 

 

I was told by my instructor that we have access to porcelain, but all the completed pieces she showed me the finish wasn't perfectly white and had cracks and such, she said this was a byproduct of the firing and nothing can be done to get rid of these imperfections!
 

 

 

 

If the pieces weren't perfectly white, then you need a better porcelain. If the glaze was crazing, that can easily be fixed. If the pots themselves were cracked, then the craftsmanship was poor. All of this can be overcome.


In Topic: Can A Candle Produce Enough Heat To Fuse Lid To Body?

13 September 2014 - 01:13 PM

So you're saying, it could happen, there it is then!  Right? Propane isn't even hot!

 

I'm saying a glaze in the direct blast of a propane torch could make the glaze soften enough to stick. I'm in no way saying a candle can melt the glaze. I am saying the pluck happened do to combustion residue.


In Topic: Can A Candle Produce Enough Heat To Fuse Lid To Body?

13 September 2014 - 12:10 PM

As a test, I put a small puddle of glaze on a brick and hit it with my propane torch. After about 3 minutes with the torch as high as it would go, the glaze began to soften slightly. It was not melted to the point that it could flow, more like thick caramel. It wouldn't even stick to the metal rod I was poking it with. Around the edges, where it was glowing the brightest- light orange- it did stick to the brick a little bit.

 

I'm thinking the mechanical bond from the wax residue to the glaze must have been the culprit. I know wax residue doesn't seem like it's strong, but we're not dealing with a layer of wax smeared on the surface. We're dealing with very tiny bits of heated residue that can fill in the microscopic irregularities in the surface of the glaze, creating a strong mechanical bond. Think of how you have to rough up an inner tube with sand paper before cementing on a patch. The idea is that the cement can go into all the depressions and have a greater surface to grab onto. In the case of our candle, the vapor was small enough to fill in the depressions of the glaze, giving a bond that was greater than the bond between the glaze and the clay. The heat of the candle in that spot also could have weakened the bond between the clay and glaze, making it easier for the pluck to happen.

 

So that's my hack scientific theory!