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Member Since 28 Jun 2010
Offline Last Active Yesterday, 11:17 PM

#120726 Complete Beginner, Epic Fail When Firing

Posted by bciskepottery on Yesterday, 08:39 PM

The clay was over-fired.  Pugging it had nothing to do with the result.


Your shelves might be salvaged . . . depends on how deep the clay melted into the shelf.  Wearing appropriate safety gear, remove the items and grind down the shelf -- use an angle grinder if the clay did not melt into the shelf.  If nothing else, remove/grind away all the melted clay and kiln wash to get the shelf completely clean, then flip it over an use the other side instead.  But you won't know until  the charred remains are removed. 


Is it possible you programmed the kiln to cone 6 instead of 06?  Did the kiln turn off properly at peak temperature?  How long was the firing? 

#120675 Is Cone 4-10 Clay Fired To Cone 4 Underfired?

Posted by bciskepottery on Yesterday, 08:08 AM

i like the fact that reality does not scare you, you have the guts to tell the emperor he is nude.



Unfortunately, the emperors (e.g., clay manufacturers) likely know this and continue to do so regardless for whatever reasons, including the one we continue to buy what they produce.  If they see a benefit to standards, they would have done so years ago. 

#120070 Fired Too Much? Or Not Enough? Help!

Posted by bciskepottery on 07 January 2017 - 02:17 PM

The trees pictured seem to be a fairly common and popular item in "paint your pottery" shops; I believe the form can be either slip cast at the shop or bought premade/bisque-fired.

The white is a glitter-type add-on after the glaze firing and the twinkle lights are installed.


And, just because there is not a recent log on doesn't mean the member has not come back to view threads as a guest.

#119974 Black Clay Advice

Posted by bciskepottery on 06 January 2017 - 08:23 AM

what is the appeal of black clay, figtree?  


Now, you really don't want me to answer that . . . or do you?  : )

#119961 Color Of Talc.

Posted by bciskepottery on 05 January 2017 - 11:04 PM

Talc is coming from a differing source . . . the old white was discontinued due to asbestos concerns.  The gray -- which I believe comes from a Texas source -- fires to white. 


http://www.highwater...in the News.pdf

#119960 Black Clay Advice

Posted by bciskepottery on 05 January 2017 - 11:00 PM

With dark clays, a good, hot bisque is needed . . . with a hold at top temperature to help burn off gases and impurities that can lead to bloating. Avoid dense stacking of the items in bisque -- give them breathing room.

You did not mention what cone you are firing to. Assuming it is cone 6, when glaze firing, try firing to cone 5 and add a 20 minute hold rather than firing up to cone 6 -- you might reduce the likelihood of bloating. The hold will bring your kiln heat work up to cone 6.

#119772 To Wholesale Or Not?

Posted by bciskepottery on 03 January 2017 - 07:35 PM

Some excellent advice can be found at these links from forum members. The first is Chris Campbell's advice on marketing, including selling wholesale. The second is Mea Rhee's writings on selling, pottery as a business, and her hourly earnings project.



#119606 Lustre / Reduction Chemistry Question

Posted by bciskepottery on 01 January 2017 - 03:47 PM

Last one: https://en.wikipedia...apor_deposition

Combustion chemical vapor deposition (CCVD) is a chemical process by which thin film coatings are deposited onto substrates in the open atmosphere.

Which is what Raku is: depositing a thin film onto a glazed piece. The crystal structure is refracting light back through the thin film; creating the optics of iridescence.

I have much to learn; I thought 'raku' (in this context) focused on reduction.. I dont see how vapor deposition has any relation to the reduction environment/oxygen depletion..  again my apologies if I'm confusing something, I thought these were two very distinct, very different processes (reduction vs vapor) to obtain luster..

I am rather confused . . . the process of CCVD described in Wikipedia -- where the vapor is part of the flame -- in unlike any raku process I've heard of, either traditional Japanese or American. My understanding is in American you can add combustibles to the reduction container (e.g., miracle gro) to get flashing etc., or you can do it with saggar firings, but that is not the same as described in the CCVD excerpt.

#119582 ^5/6 Glazes

Posted by bciskepottery on 01 January 2017 - 10:27 AM

Are you using Krakowski's Albany Substitute as a glaze by itself or as a substitute for Albany Slip in another glaze? Her intent was to formulate a substitute for glazes calling for Albany Slip -- which is no longer mined. There are several recipes out there for Albany Substitutes. You can shift the color of Albany Substitute towards black by adding up to 2% cobalt carbonate.

Xavier's Warm Jade seems to be sensitive to thickness from the times I've used it.
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#119567 Can Tall Teapots Like These Be Handbuilt? These Are Extruded

Posted by bciskepottery on 31 December 2016 - 11:01 PM

The extruder allows you to achieve an articulation or animation in the form that is hard to replicate with slabs. Not saying it can't be done, but the joined edges of the slabs will be a weak point as you twist the form to get articulation and movement.

#119486 How To Charge For "samples"

Posted by bciskepottery on 31 December 2016 - 01:07 AM

Sounds fishy to me -- perhaps a scam. Is the requestor valid and legitimate?

#119455 Any Opinions On Paragon Tnf-27-3?

Posted by bciskepottery on 30 December 2016 - 04:23 PM

"Any other opinions or concerns for this kiln?"

Check the condition of the bricks -- for any broken bricks, bricks with glaze drops, etc.
Check the elements/holders --
Check to see how the top sits on the kiln -- any large gaps? does hinge work properly?
Ask to see the firing log for the kiln -- that will give you an idea of prior use and type of use
Ask when elements, relays, thermocouples were last replaced and how many firings they currently have on them
Check the plug for signs of overheating, fatigue, discoloration, etc.
Ask that the kiln be turned on an hour before you get there so you can see if the elements, etc. work.
Make sure you have the right electrical hook up on your end.
Check the voltage -- schools/community studios in warehouses may be on 208v while your home is 220v.
Ask if it comes with furniture -- shelves, posts, etc.
Depending on age, ask what the kiln was fired to cone wise and what types of glazes ere used in it (hopefully, no lead).
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#119251 Pigmented Glaze Issue!

Posted by bciskepottery on 27 December 2016 - 02:50 PM

Rather than mix the stain/underglaze with the glaze and spraying over the base glaze, consider just spraying the underglaze/stain on the base.  That way you are not increasing the thickness of the glaze application. 

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#119247 Check My Work

Posted by bciskepottery on 27 December 2016 - 01:44 PM

Glass can work for decoration.  But for functional work -- on insides -- not a good idea unless your glass and the glaze share the same COE.  Otherwise, they are going to heat differently, expand and contract differently, and cool differently -- every time the bowl or mug goes into a microwave or oven.  Eventually the bonds will loosen and craze, crack, shiver, etc. whether the piece if functional or non-functional. 


If you look at the finished piece in her gallery, you can still see outlines of some of the pieces of broken glass used . . . not completely melted. 


Makers need to understand how their materials interact and the limits of their materials. 

#119246 Your Experiences With Stain/s

Posted by bciskepottery on 27 December 2016 - 01:39 PM

Asnd I don't know if this is a common problem, and I rather think it's something in the base slip that's causing it. The artist said she was using a friend's white casting slip as a base for her stains, and putting it over something she called B3 ( I am unsure of the manufacturer: it's not a clay that gets shipped to my location.)

Less to do with the slip than the dark clay body. Had this happen to me using Standard 266 with a white slip on the inside. The slip was too thick and the clay could not off-gas properly, resulting in those ugly blisters/pocks. Need a hotter bisque/hold at top temp to get rid of the gases. And thin the slip. Slow the cooling to allow gases time to burn off before the glaze seals. Might be better off using underglazes than slip.