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perkolator

Member Since 08 Feb 2012
Offline Last Active Yesterday, 10:55 AM
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#52281 Clay Body For Large-Scale Project

Posted by perkolator on 12 February 2014 - 11:18 AM

Yes, Arneson used to build some thick, solid work. Our methods were pretty much initiated by him, and were passed to us through George Grant (he was tech for like 25yrs) and our Faculty who has also worked in thick, solid ceramics most of her career. We haven't changed a whole lot in our process and our firings still take 5-7 days before work can be unloaded due to the scale and method (also because in a 10wk quarter system makes challenges when working this big).

We don't have humidity issues here in CA, we're actually in a severe drought - so drying should be fine, if anything it would be too fast. With a high grog content on other porosity added to the clay body, the pieces will dry out even better at the core where it's most important.

The piece will be a big relief that starts with a base around 3-4" thick. It will likely get both carved and added to. Piece will get cut up and put on boards (or will already be cut into tiles beforehand) and then onto ware carts for drying. Whole cart will be under a plastic sheet to slow it down. Anything not fitting on the carts I'm going to have to rig up some sort of elevation system to get airflow under the work like Marcia mentioned with the sticks, only with multiple levels due to volume of work and because many carts will be occupied with student work. I don't like to push force drying too fast, but bringing the carts into the heated building will help, as will force drying in the kiln if need be. It'll likely take a month for the work to dry enough for firing is my guess.

Firing will be in downdraft gas kilns, fired over the period of perhaps a week and cooled over several days as well. With the thickness, it will likely need down-firing to keep from cracking in cooling. Individual pieces will be flat on the backside, so they will all get propped up on balls of kiln wadding (equal parts silica grog kaolin) when placed in the kiln.

This has all happened really fast and I dunno who's idea it was to at the last minute decide to have this huge ceramic piece/demo as part of the event. This is not really one of those things you take a last minute approach like this, but we're doing it. If anything, this will be a big, fun experiment with tons of clay! It will get lots of documentation, no worries there ;)


#51376 Price Of Fuel Slowing Anyone Down?

Posted by perkolator on 30 January 2014 - 04:18 PM

Kind of off-topic, but has to do with fuel prices....

 

Yesterday, Jeff Chown from Blaauw Kilns came to our class and did a powerpoint regarding the innovations in kiln firing tech that they are now implementing in industrial ceramics (since all of our current ceramics-related tech has been passed down to us from industry).  I was very surprised to see that with the way these kilns are being designed these days, energy/fuel consumption will be drastically reduced.  

 

Jeff gave some examples comparing old, updraft hard-brick kilns to the new fiber kilns and there was something like a ridiculous 75% fuel savings for the same firing results.  Some of these kilns in industry (depending on what's inside) can be fired (AND COOLED) in a 14hr period to ^10!!!!!  

 

I know that I personally will never be able to afford one of these beauties, but man has kiln tech come a LONG way in the past decade or two.  If you're looking for a serious way to save on fuel costs, cough up some dough in the beginning and watch the savings add up with each firing!

 

I'm still in amazement with what was presented to us...




#43667 Beehive Kiln?

Posted by perkolator on 03 October 2013 - 05:50 PM

Nearby my location we have Gladding McBean, where they have several beehive kilns that are still used for firing sewer pipes.  They are pretty big, maybe 25ft tall, 30-40ft diameter, downdraft kiln powered by 6-8 natural gas burners.  I believe they fire them up to around Cone 7 and it takes around 3wks (1wk preheat, 1wk firing, 1wk cooling).

 

here's our students going through the beehive kiln room/warehouse a few years ago when you could still tour the facility:

photo (15).JPG

and one off the net:

Beehive%20Kiln.jpg

 




#42055 Clay For Large Figurative Sculpture

Posted by perkolator on 04 September 2013 - 01:57 PM

based on what you've said, i think ANY sculpture body would work just fine in your application.  you will want something with a decent grog content (fired clay that's ground up) as opposed to something that's smooth, like a throwing body.  if you can find an architectural clay body, that would be even better for the large-scale items you want to make.  the fire clay we use is the base of our clay body because it's local to us and therefore very cheap - unless you are planning to make your own clay, which i'm assuming you're not, then i would recommend you call up your local ceramics suppliers and discuss with them your project to see what clays they stock.  i'm the ceramics lab tech for UCD.




#41991 Clay For Large Figurative Sculpture

Posted by perkolator on 03 September 2013 - 03:23 PM

kind of a loaded question.  depends on a few factors.  since you mention "water based clay" i'm assuming your experience is with oil based clays?  also, what are you considering "large scale"? (like life-size human figure sculpture?)  how are you planning to build? (armatures for support? solid or hollow forms?)  also, how fast are you building? 

 

students in my studio are typically producing large-scale sculpture (2-6ft tall, up to 1-2" thick).  we use a house-made stoneware body that's mostly Lincoln Fire Clay with 5-10% 20m grog content.  most sculptures are built in a week's time, always hollow forms with no support structure/armatures.  typical firing is to ^04 or ^5/6, usually once-fired over a 3-5 day schedule.




#41259 Cone 5 B-Mix

Posted by perkolator on 22 August 2013 - 04:51 PM

got a pic of how it's cracking?  like cracking from the lip?  i've used b-mix plenty of times, never really had any issues.  sounds like your issue could be due to a lack of compression or maybe oversaturation of the clay body when throwing.  hard to say without seeing where/how it's cracking.




#41125 Why Earthenware?

Posted by perkolator on 20 August 2013 - 03:15 PM

the issue is not necessarily always about fired strength or vitrification - since you can achieve both at either temp.  there is however a pretty good difference in energy cost, firing time, wear on kiln, color palette, etc. between the two firing ranges.




#36192 Looking for a red glaze like this one

Posted by perkolator on 30 May 2013 - 06:47 PM

i'd say those raspberry red glazes aren't very close to the type of red you're trying to achieve. usually those chrome/tin reds are more of a fuschia IMO, at least that's how mine have always come out. I use the Lana Wilson recipe or similar.

i would love to be able to find a nice copper red recipe since mine seldom come out the "chinese red" (vermillion red) that I've always associated with copper reds. it's always been my understanding that many of these red glaze recipes are held under lock and key so nobody else can replicate them since they are so elusive and require a reduction-firing genius to get them to turn out correctly or be burned off.

Anyone know what the company making Crate & Barrel's ceramics uses for their sweet orange-red glaze? I figure it's commercial. Have no idea how to achieve such a bright color like that, but would like to know!


#30090 Pyrometer: Skutt 343 vs Fluke 50D?

Posted by perkolator on 28 February 2013 - 07:53 PM

i've been using one of those Skutt handheld pyrometers for the past year and a half -- no complaints! bought it to replace a really old Fluke 51 that bit the dust and was going to cost more to repair than buy the Skutt.


#27483 Firing electric kiln in wooden shed

Posted by perkolator on 07 January 2013 - 06:32 PM

you should be fine without venting the shed unless it's really air tight, but a vent would always be better. personally, i would not work in the shed while it's firing unless it's well vented. since it's outdoor uninsulated shed, you should not expect the temps to rise a whole lot especially in the winter - really depends on how long your firing is as most kilns are fairly efficient at keeping the heat inside. keeping a nice perimeter clear from the kiln is a good idea in general - also, adding a cement board product (hardibacker, durarock, etc) to the area your kiln is located might be a smart $20 investment since it's a wood shed.


#13322 banding wheel stuck!

Posted by perkolator on 10 February 2012 - 11:38 AM

If this is an eBay special banding wheel that costs around $15 then it is most likely one of the stem-style that is just a shaft inside a sleeve with some grease to help it slide. These types don't last long and will freeze up unless you keep it lubed. Since they're aluminum they tend to oxidize pretty bad inside. I would suggest the penetrating oil and leave it upside down for a while. You can also try smacking it with a hammer on the center of wheel head to break it free, then put feet on the base and grab the head to try to loosen it up. Either way, these are not built to last and you may have to replace.

If your banding wheel was a few hundred bucks and weighs a ton then you've got a GOOD one like a Shimpo. These are built to last with heavy duty materials and are built with serviceability in mind. Turn it upside down and you should see a nut to take it apart. The bottom would most likely have the brand name stamped on it for these nicer banding wheels.