Hulk
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I'm using Lakeside Pottery Clear Blue; it goes on and fires well, does not move much, and is fairly consistent over edges.
The formula is on Lakeside Pottery's website; it's been copied to Glazy as well:
Clear Blue | GlazyIt does call for Talc.
I'm using the no longer widely available C-98 talc, and have enough to last several years, however, if/when the supply runs low, I'll be testing alternative sources of MgO, an important part of several glazes I use and really (really!) like...There's some lightening at the edge of the knob, which may be difficult to avoid with any transparent blue over white clay; any road, it lays flat and doesn't move, excepting if put on very thickly.
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Hi Johnny, welcome to the Forum!
The product is "... technical porcelain stoneware.." slab?
Which product/finish? Looks like there are only a few that are one solid color, the others have a pattern/variegation.
All the Calacatta in the catalog ("Book 2023") have some variegation.Any road, consult with the installer and/or product rep might be in order.
My guess, it would be possible to stain the material, however, looks very stain resistant.
Is the material matte or polished finish? Was all the cutting/polishing dust buffed off?
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We had baseboard heaters in the first house we bought (some thirty years ago). We took them out, added insulation to the overhead, insulated the floor, added cellular blinds, got a more efficient/modern wood stove, and cut lots of firewood. We were trying to keep our electric bill down*.
Any road, with "strip heat" (aka resistant heat, metal that heats up, like our electric kilns) we get out about what is going in, hence, add more watts to get more heat. My guess is the same wattage heaters heat about the same, whether baseboard, portable, etc. The direction/focus of radiant heat, however, that's a comfort factor, as Min points out!
I'm still planning on a heat pump for the new Studio space (we moved this year).
It will cost, up front, however, more efficient in the long run**, does both cooling and heating, and we'll size it to handle the extremes, hence it'll be chugging easy most of the time.
**aka "mini-split" - the units move heat, which takes less energy per unit of heat than "generating" heat.
The newer/better units heat well even when it is very cold outside...*electric where we are has gone up more, faster, this last year than ever!
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Hi Mereia,
Welcome to the Forum!
Good question.
What toxic materials are at issue? -
Hi Tbeans,
Welcome to the Forum!
Good questions.
Drying the slurry to the desired consistency could be an approach; ladle off the clear water, mix thoroughly, then dry*.Several clay vendors sell powdered clay - saves on shipping costs - however, the clay you end up with, very likely, will have different properties than what you started with.
You might get in touch with local and/or preferred vendors to inquire about dry/powdered stoneware.
I know I've seen dry clay offered by vendors in California.
Aha! Here's an Idaho store's page featuring some Laguna Cone 5 clays, fifty pound bags
50LB Bag Dry Clay – The Potter's Center (thepotterscenter.com)Whether you dry out what you have, or add dry stoneware to it, either way, you might start with a sample, then test its working properties, how it fires, how it takes your glazes and finishes?
Same as for any unknown/new clay, test to see how it works!
*There are several methods for drying out sticky wet clay.
I ladle the goop onto plaster slabs, then turn and wedge it periodically until it is ready to bag.
I've seen and read that others bag the goop in tied off jean legs, into pillowcases, et cetera...
It's a bit of work, however you go about it! -
Good question!
I feel and think (both!) that I'm just starting out with trying and choosing clay bodies ...I've found three, err, four clays that I like, three of which a nearby* supplier carries.
I still like periodically rotating from white to red to buff/brown.
All the factors Pres listed apply for me, excepting "word from others..."
For white and buff stoneware, I like low absorption (less than 1% preferred, else 1.5%), almost never has "gassy bits**" and tolerates a cone or more overfiring without issue.
For red stoneware a bit higher absorption is ok (unless/until I find something better), almost never has gassy bits, tolerates just over a half cone or so overfiring.
My low COE liner glaze has to fit Very Well, and my colored glazes have to fit well.The clays I've tried and won't go back to have one or more of these characteristics: expensive, high rate of gassy bits failure, my low COE liner glaze doesn't fit (crazing), misbehaves horribly when overfired a wee tiny bit (fizzing, bubbling, turns purble, melts/slumps), absorbs water too quickly while working (giant globs of absorbent grog in there), is just too sandy/lumpy and or the sand is sharp (is there any good reason for sharp sand in clay?), varies considerably/intolerably batch to batch.
When next buying clay (almost certainly the same three clays I'm using now), I'll want to know if the recipe has changed since last purchase.
There's the talc change thing, and I've already had a "this is Totally Different Clay" experience with another vendor's product. Even if assured it is same, I will test! !!
Likely I'll also get a fifty-pound box of something to try, which is how I discovered the speckled buff that I really (really) like.I prefer the clay right out of the bag to be a bit softer/wetter than I want to work with, which is easily remedied by a turn on the wedging board.
Somewhat related, I don't want clay right out of the store to be "old" already - fresh, please; nor do I want clay that's too stiff/dry for my taste.Stacking the boxes together in a shady and cool spot, then covering tightly with a tarp seems to help keep the clays "young' ...now I wrap the boxes with moving wrap before stacking them up, seems to help. The moving wrap is like a gigantic version of the cling wrap used to wrap food.
*the nearby vendor is just under 100 miles away, IMCO in Sacramento. They make a white and red that I like, and they carry a Laguna product that I've tried and like. Another California clay vendor has a white and red stoneware I like, but they are further away, and I like the nearer vendor's clays a bit better, not Just because they are cheaper, no, the white is more consistent, and the red has better working properties, tolerates overfiring better, and is less absorbent ...and their clays are less expensive.
**where there's a large pit/hole in the glaze, which I'm guessing is due to a large piece/chunk/bit of something that off-gassed enough to create a volcano-like effect that's too big to heal over. I'm willing to tolerate this when it doesn't happen very often, at all, like one of twenty wares - not so much one of seven.
Added: That Dragon Fruit clay has been whisperin' to me!
- Pyewackette, LeeU and Pres
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Where there is a very slight difference in COE, a thicker glaze might show a crack where a thinner layer wouldn't (depending on some associated factors...).
COE is fundamental to combating crazing!
Materials expand and contract as they heat up and cool down, respectively.
Where clay and glaze expand and contract at rates that are different (enough), problems happen!
At one extreme, bits of glaze pop off the work, shivering, and at the other extreme, the glaze cracks, crazing.Crazing can be ameliorated by changing the glaze formulation/composition, also by using a different clay.
You'll hear and read the term "fit" and "glaze fit" - where the glaze "fits" the clay, there aren't shivering or crazing problems.Here's links to some articles:
Co-efficient of Thermal Expansion (digitalfire.com)
Glaze Crazing (digitalfire.com)
...and a few threads from this Forum:
Crazing Clear Glaze - Clay and Glaze Chemistry - Ceramic Arts Daily Community
Crazing question - Clay and Glaze Chemistry - Ceramic Arts Daily CommunityThe cracking depicted in the OPs image (first post, above) seems a special case to me - typical crazing forms a pattern, where a large pattern indicates a closer match than a fine pattern. I'm curious to know if the clay is cracking, or is it the glaze?
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I have several of these inexpensive plastic calipers*, handy in the Studio, a few dollars at your local hardware store or online.
If/when they break, bend, wear out - not a big loss!Plenty accurate within a small fraction of a mm (depending on one's eyesight); the vernier is decent.
Typically, the depth bit on these cheapies don't line up with zero, but that's easily accounted for...For larger wares, I'm using a fifteen inch Fiskars stainless steel ruler, graduated in mm and inches, which I find handy...
*when a more accurate measurement is required - within a thousandth or two (inches) - I'll break out a spendy caliper or micrometer.
I haven't yet needed to use any expensive measuring equipment when working with clay. The one exception was testing to see how small a vertical wheel head wobble is perceptible - a few thousandths is enough to be annoying, yep.In my ceramic practice, within a fraction of a millimeter is almost always "close enough" - and for ordinary projects as well, e.g. bolt/screw/drill size, blind hole depth, et cetera, a cheap plastic caliper is practical, useful, and low ri$k...
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Detailed notes might be helpful, as new accidents may occur (likely), and some o' them happy as well!
I wanted to suggest using cookies, just in case, aka waster slab, a thin slab of clay the glazed ware sits on, which will prevent running glaze from pooling up on the the kiln shelving.
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yep!
In my limited experience
on one end, a red clay the vendor rates 6.5% absorption at cone five doesn't tolerate firing much higher
my measurement indicates absorption between 4 to 5%on the other end, a white stoneware the vendor rates at 1.5% absorption at cone five tolerates overfiring better, but I just fire it to a solid five
my measurement indicates absorption between .3 to just less than 1%iow, depends on the clay.
However, a slightly absorbent terrarium water dish might be ok, if it doesn't mold up?
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Testing tells the tale!
I've tried mixing clays in reclaim - just once so far - was not pleased with the results!
Two of the three clays in the mix had some problems I'd hoped would be ameliorated by the third clay.
The "good" clay was just over half, by volume, and the most problematic clay less than fifth; still, the "bad" showed through, big time.I've just bagged some buff reclaim this week, where I tossed in a small amount of speckled buff with the other buff.
Both clays "behave" - hence I'd like to expect that the result will be great.
Still, I plan to include just a few pieces and some test tiles, test test test! ...then go from there. -
Hi colormek8art,
Welcome to the Forum!
Wow, that kiln looks to be in good shape.
While waiting on responses, could you confirm the phase requirement; is it three phase?
Also curious, what are the amperage and max temp ratings?
To test/run safely, the wiring must be proper.
The max temp rating could be important; what temperature target/range do you work in? -
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State of Louisiana, City of Los Angeles, or?
There's Louisiana Mud Mavens Ceramic Art – Louisiana State Exhibit Museum (laexhibitmuseum.org)
and Current and Upcoming Exhibitions (nolaclay.org)The drive through daquiri in Lafayette used to have "two-for" Tuesday (on Tuesdays) ...crawfish season is mostly over, but there are many other wonderful regional eats!
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Good question!
I'd be tempted to widen the definition of "tools" to include track shelving* and a rolling cart.
Then a few more buckets.The Studio needs (aah, I need!) the wall put up and mini-split installed; so, so hot!
I'm good for tools right now, looking forward to setting up and firing the new kiln when it arrives!
There's some open space in the Studio now, but still lots of organizing, demo and remodeling to do.I'm getting lots of miles out of relatively inexpensive (it's $26 on ah maze on right now) US Balance "US-Benchtop-Pro" scale; it performs consistently and well.
Its max is 2000 grams, hence, for larger glaze batches, there are more steps.
If choosing again, I might go with the 3000 or 5000g models, maybe; the 3000g model can be had for less than $40 ...
*I like the metal tracks that screw to the wall; shelf support brackets snap into the track.
Higher up and on the end there, for glazes, glaze materials and some other stuff that's nice to have handy but aren't used every day; at "wheelhouse" level, green and bisque ware queue-up space. -
Callie moved the topic to Studio Operations and Making Work - where it is now!
I'm not finding the topic's original location... -
Tough question!
Parian* is generally defined as a "self-glazing porcelain" which appears to have nearly zero absorption.How are you using Parian?
Do your finished wares absorb water, at all?
*Composing a Workable Parian Clay Body (ceramicartsnetwork.org)
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Hi Laura,
Welcome to the Forum!If you're painting over where the holes are*, a vinyl spackle might do; the initial application typically shrinks, hence a second application may be required.
Check back for more responses...
*I'd be concerned that the paint sticks to the glaze. Perhaps a light sand/scuff, then prime and finally paint.
Test first! -
There are many clay choices that mature at cone 5/6 with very low absorption.
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LED lighting might be worth a look - long lasting bulbs, high efficiency wins back the initial cost, and then more from there.
We used LED fluorescent tube look-alike replacements at the last house, particularly in the garage and Studio.The round ones ("canless" recessed) that go into the ceiling are very reasonable now; we used them in our Son's bathroom remodels last summer. The light "temperature" is even adjustable!
Our new house has them in the garage.
On the Studio side, I plan to chain in several more.
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Hi BlueSky,
Welcome to the Forum!
I like that clay*.
If you pluck a bit of kiln wash, it does come off fairly easily.
I'm not seeing the IMCO Red Velvet Classic pluck any more that the other clays I use.I smooth and polish pot feet with round diamond pad that I have glued to a bat - wet the bat, work the pot around flat, then tip up to round off the edge a bit, voilà, done!
Before getting the diamond pad, I used fine sandpaper - the "wet" kind - taped down to a board, same principle, more work (the spinning bat helps!).
Wet, to control dust.
For a big chunk, I'll dremel it off to get close to flush/flat, then finish with the diamond pad or sanding board.
Four hundred grit is likely fine enough, yet still works fairly fast.Dremel makes dust, so I'll head outside and put the respirator mask on...
Hope that helps! Check back for more responses in a day or so.
*I really like IMCO Red Velvet Classic; it's plastic, dries well (better than other reds I've tried), has a nice color.
I also like the DC 3-5 (white-ish stoneware)
My experience with red stonewares - they can be sensitive to over firing, even firing right at the high end of the range - with fizzing/bubbling, turning purple-ish, and sticking/plucking. The Classic seems to tolerate a cone 6 ok; I haven't pushed it higher yet...
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QotW: What are the steps you take after glaze firing with each finished piece?
in Int'l Ceramic Artists Network (ICAN) Operations and Benefits
Posted
Unload, inspect, polish feet, wash, price, photograph, store/stack/deliver.
I inspect as part of the foot polishing step.
I try for a time when the natural light is good, and the weather allows rolling up the door for more sidelight. Good light really helps.
I pull the OptiVisor down for a close visual inspection, pick up and put down the ware several times, wave them about - checking heft, balance, feel - then flip up the OptiVisor and polish the foot.
The ware that doesn't make a-1 may go to the discount collection, our own kitchen, the to be drilled for planter queue, else smash and trash.