Hulk

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!

It depends.....  Some people are heavier appliers than others.  Commercial glaze usually says apply 3 coats.  I have seen people apply three coats that look like my 1 coat, and others whose 3 coats would puddle all over the kiln shelf.
At our community centre, I get newbies to do a "number of coats" test tile, before they do any glazing or underglazing.  A square tile of clay, marked into 4 smaller squares.  Corner 1 gets one coat of underglaze, corner 2 gets 2 coats, corner 3............etc
This gets bisque fired and then they apply 1 coat of clear on half of corner 1, 2 coats on half of corner 2..........
Second fire to earthenware, (we don't do any high-fire) then they (I) can determine if they are a light applier or a heavy applier.  This gives them a guide for future applications.    
We often repeat with a vertical tile with texture.

The maddening answer to just about everything in glazing is “it depends.”
IF it’s available to you, clear glazes are usually much easier to apply thinly and evenly via dipping. If it’s not, then brush away. 
If you’re mixing 2 glazes, this can often result in special effects that are partially due to running. When starting out you might only want to apply 3 layers in total, however you want to divide it out. Usually you don’t need a clear glaze over other glazes, unless you’re hoping it’ll do something interesting. If that is what you’re going for, make sure you have a waster or a cookie under your piece to catch any drips. Cleaning kiln shelves is not fun!
 Learning how to apply glaze is another skill that takes experimentation and practice to get the hang of, and it’s a good idea to do some test tiles before you start glazing your favourite piece. Recommendations on the label should be considered starting points. Your idea of a thick coat and someone else’s might not be the same thing, and you have to play around with it a bit to find your sweet spot. 
Generally clear glazes want a thinner application than other things for best results. An overly thick clear glaze will go a bit cloudy. This effect is more noticeable on dark clay or underglazes than it is on lighter coloured things. 
 

Thank you for sharing your experiences and suggestion for the downdraft vent, it's much appreciated! And yes, clearance will be important, it's a 200 year old barn and I hope it will outlive me too!

I want to thank everyone for their responses.   Very helpful.   I actually have the Hamer book and the section on cracks is great.  Years ago,I used the formula "Rhodes" celadon for my blue celadon glaze. This glaze has a lot of Cornwall stone, which I thought may be the problem.  It started to craze in the manner I described, so I increased the silica, but the problem persisted.  I was frustrated and chose to  test other celadons, and found another beautiful one, which is the one I am now struggling with.  This may be a silly question, but does the addition of bentonite lower the COE of the glaze?  This glaze sinks to the bottom almost immediately when mixed, so I've been adding perhaps too much bentonite.
I'll be researching on Digitalfire per Hulk's links.   Thanks so much for these.  

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 Community
The 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?

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!

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 Community
The 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?

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!
 

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!
 

The look of the fired unglazed clay is my essential criteria. Unless I'm checking out a new-to-me black/gray, I go to great lengths to avoid staining - usually go for whitest/lightest bodies, but they can't be soft/slippery. I usually get somethign with a bit of tooth/grog/sand, recommended for handbuilding. I don't care about absorbsion  or shrinkage for what I do.  Suppliers tend to have helpful, knowledgable, customer service people who have never steered me wrong. At the moment I am in love with Dragon Fruit, from International Clay & Mnerals Co. ICMC   Very light gray with fine speckles and feels like stone...makes for some interesting contrast with glazes (but not for total coverage-that just wastes it's beauty). 

Going through the clay charts at Standard Ceramics lately, and thinking back to all of the interesting thoughts and discussions I have heard over the years. Wife says: Oooh!  that's a pretty color why not that one? Hubby: stains everything, absorption is too high. . . glazes wont fit it.  Wife: Aww you could do it. Hubby, Not interested! Wife: Oh. So how do you decide on a clay body, is it price, or fired characteristics, or working characteristics, or even just because you always use it, or is it word from others passed along?
QotW: When buying clay bodies, what characteristics do you look for in the clay? Especially when buying a new body you have never used before.
best,
Pres

Thanks for the info.    Looks like I have some work to do.
The glaze is cracking, not the clay.  

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...

Thanks guys, much appreciated. Hulk, I've been thinking along the same lines, keeping moist spots might keep the hermit crabs happy they do like to dig. 
Graybeard 

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.

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.

That glaze does not have any Gerstley Borate. There is no way it would look like that unless you under-fired it. The fact that you can put another glaze on top of it and it is still mostly on the test tile means there is definitely no GB, unless that other glaze on top has absolutely no frit in it?
So if you wanted to replicate that glaze and figure out what it is, I would do this.
1. Since you said you had a few unlabeled bags, I would mix up that exact glaze but missing the 50% GB.
2. Figure out how many cups you want to use, so say its 10 attempts to figure this out. Measure out 100ml of glaze with the mystery recipe but don't include the Gerstley Borate. Instead leave that out. But use the same amount of water you would have used if it was in there.
3. Measure out 10ml with a syringe into each cup, making sure you stir well before each one. I use a milk frother for this...
4. Take your 10 mystery attempt materials that look similar to Gerstley Borate that you might have used instead. Put 50% weight(the missing GB amount) of the mystery chances into each cup. You will have to do the math on this to figure out what this should be, but it isn't difficult at all.
5. Glaze a test tile or a little test dish or whatever you want in the 10 mystery glazes and make sure to record everything.
6. Fire it all on the exact same schedule with the same load mass that you did for the first tile.
7. Pull out the results and keep any of them that look similar to the original tile, go from there.

As a Moderator, I am letting the Forum community know that there is an App out there for doing much of the organizational work for arranging classes, firing the kiln and measuring what is fired. Just do a google search and it may be yours at a price. Listing such is against the Terms of Use for the forum. Thank  you for your patience.
 
best,
Pres

depends on the tightness of the clay body(what cone 6 clay  body)-the absorbion rate? Usually clay needs a glaze unless it really a tight body.

Lately I have been using the stencils, stamps and branches etc directly on the slab after rolling, actually embedding into the slab a design. In the slab piece here, I used a large slab, decorated completely then cut to slabs for use so the design went around the piece. After bisque, cobalt and iron stains were used under the glaze,  
Glazing was completed using dipping, pouring and atomizing layers of opaque, and transparent glazes to build up the surface.
best,
Pres

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?

Most glazes I’ve used benefit from slaking overnight before sieving. Given Tony says that Tile 6 “is relatively impermeable to water compared to other kaolins, it is thus the last choice for casting bodies,” I’m curious what the comparison is between the glazes a week later.  
Side by side, there seems to be a few more impurities in EPK than Tile 6. While the flux comparisons have some variation that might need watching in a glaze formula, the silica and alumina balances are close enough that part might not matter. 
Tile 6  is known for its plasticity in clay bodies, which I can confirm from personal use. The plasticity may have an effect on some high clay glazes where shrinkage could affect application, but that’s theory on my part, and if someone knows better, speak up. 
As to why a material might be washed and another isn’t: we have to remember that potters are a secondary market for almost all of the materials we use. EPK I think gets used to make glossy magazine paper. If tile 6 is mined for something else, the washing may not be necessary. 
Edited to add:
Links to Digitalfire materials pages for comparison. 
Tile 6 writeup
EPK writeup

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!