Hulk
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Posts posted by Hulk
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Probably need two or three sets of hands to liner glaze that pot!
Maybe
a) a piece of scrap carpet (or somewhat) on the floor to pad the base
b) something to lean the pot on so it sits at 45° or so, and can then be tipped up and rolled along the length of, also padded with carpet or somewhat
c) a long pan to catch the poured-out glazePour glaze in, lean the pot over on the thing, lift the base* to the point where the glaze is about to pour out, roll the pot along the something whilst pouring out!
Voila?
*Risk, of course, that the pot breaks on the pivot point, hence, larger and softer could be better.
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Hi Michael,
Thanks for sharing this, nice work!
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Zombie skin, I have that!
:|
I've been filling the chatter marks since early on, which prevents little micro-crawls, where the glaze didn't wet all the way to the bottom of the mark, and, there's opportunity for highlight/contrast.
At first I'd used underglaze only; now I almost always use a glaze.
Depending on the materials, the marks can be accentuated, muted, and somewhat in-between...
I'm dampening the area with a sponge bit, then floating the material on the marked area - wet brush, pick up the glaze/underglaze, flow it on - the material goes right into the marks, less so on the surrounding area. Then wipe all with a sponge bit, leaving the marks filled and the surrounding area clean.
Allow to fully dry, glaze.I'm still working on technique - get the marks filled in less time with less waste...
The little round sponges that come with tool kits, they are good for wiping away!
However, cutting purpose shaped bits from a larger sponge works, thanks Bill Van Gilder for the tip... -
Do transparent and/or translucent glazes show texture better?
Highlighting textures with contrasting washes/underglazes/glazes - put on, then wipe off, leaving some behind in the lower and rougher spots - may help. -
This thread has been resonating!
I went to post-secondary school with Engineering candidates who had: never (or hardly ever) used a caliper, dial indicator, or micrometer; never read a vernier; to stop to think which way to turn threaded fasteners; little or no layout experience; little knowledge of lubricants, bearing maintenance, belt tensioning; little or no experience with any cutting tools; had little or no soldering, brazing and welding experience ...looked to me that "it's harder" without practical experience.
Hands on! "Learn By Doing" see also Cal Poly
How nice for students to have at least One Class they like and look forward to.
How often is "that one class" Music, Theater, Art of some kind, Shop of some type, Sport?
What are those type of experiences without the crucial performance, work/wares/product/piece, material and finishing, contest/activity?
...like pottery without a kiln. -
I haven't circled back on the HardiPlank bats; I'd left the power sander at our son's house.
The test bats had a few quick swipes with sandpaper, which helps; I have one piece that's been more thoroughly sanded, but haven't put holes in it yet...The HardiPlank bats do move(absorb) some water, more than my powderboard bats, but not as much as the plaster bats.
Hence, wiring off ware comes sooner than with powderboard bats, but they don't "pop off" like with plaster bats. -
Adding fans, reminds me of a solution we used for a P100 (a computer, new circa 1994; it'd been in continuous service for fourteen years) on a production line in the Steel Mill.
The fan in the power supply had failed; upon opening the box, we found a rather thick layer of glittering dust (dirt, dust, insect bits, and metal particles) on everything.
After blowing it out and replacing the power supply, we circled back to add an input fan (blowing in*), fitted it with a filter, and made a calendar item to check/clean the filter in six months.It was still chugging away when I left the Mill. There was a bit of yelling about it - the Sheet Division Manager wanted to know what IS THIS!? Who's behind this joke and it ISN'T FUNNY!! All heads turned to Murf, heh, oh we had a good laugh on that one!
*where the input fan blows harder/more than the power supply's fan, the inside of the box stays much cleaner.
We used a simple and inexpensive motorcycle carburetor foam sock style filter, easy to mount, easy to clean.
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Peter, I'd copied the quote to the notes I was keeping whilst reading up on eutectics; I wanted to credit the source.
I'm not finding it again, almost sure it was from potters.org; sorry I haven't found it, I did look!"hmmm" on account of several notions it points to (imo):
Several authors point out that dissimilar particles in a dried slurry behave differently on heating than powder ground up from previously melted/solidified material of same proportions.
Typical glaze slurry may have several eutectic "things" happening, much more complex than the three legs of a pyramid.
Liquidation and solidification likely occur over a range of temperature change and takes time (like butter, as others have pointed out), which is probably good.
As for "Why?" does my liner glaze with the talc have less excess Silica and Alumina, per EuCal, than the "same" glaze without talc (MgO) my guess is that untangling the math would answer.
From there, testing could prove. -
This thread (and the thread it spawned from) piqued, err, re-piqued my interest in eutectics, generally, and also the role of MgO in mid-range glazes, specifically.
...then I thought it best to let it ride for a while; time's up, for forgetfulness looms!
The triangles (and pyramids), surely, don't capture the complexity of even the simpler glazes.
The articles I'd like to read co$t.
Others have, over centuries, conducted tests, lots of tests*...The Excel workbook EuCal_ver_1_91 indicates there's less excess Alumina and Silicon in my liner glaze when 6.3% talc (Texas) ingredient is included; I believe the differences are significant.
With talc .33 and 3.24, Alumina and Silicon, respective;
W/O talc, .51, 4.36Why?
Lots of work went into that EuCal!
The talc in my liner glaze, it's for lowering COE.
Per my testing, it helps with that.Eutectics, hmm. Jess McKenzie, "The point where the liquid solidifies is more to the point than where the dried slurry of mixed powders liquifies."
hmm
See "liquid phase sintering," "Quaternary Piercing Point," "deformation eutectic," Ian Currie's book, particularly the MgO chapter, and lots of other stuff. ...then get back to work!Frits and mixtures of different powders - expect them to behave differently, for they Are Different.
Melt, ye glaze, then hang on the pot without moving (much) over a range of temperature - so I have some wiggle room with the heat work - there, d'ya hear me, Glaze Spirits? Bond to the clay, provide a smooth sound wear resistant surface, be beautiful (at least interesting, err, not hideous?), inert, and uncracked.
*test, that is "where it's at!"
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Hi Py, Good-oh on the garden, wish I was closer to Nowhere, to trade somewhat for a few bushels...
I'm using:
i) a kitchen whisk to stir up the glaze between dips/pours
ii) a smaller, wooden handled kitchen whisk, which I've fitted with a pin that chucks into the drill motor, for powered whisking!
iii) a long straight scraper that has a square end, for scraping down the sides and that bottom corner of glaze buckets
If it's been more than a few weeks, I'll mix, then screen (80 or 100 mesh) the glaze, then get to work.
My newish cordless drill has two speed ranges, and a smooth ramp on the trigger, hence I "hardly ever" make a splattery mess. Hardly. Ever!
If ever in the market for a drill motor, check the heft, feel, and, And, the trigger action under power...The hand driven whisk is plenty enough to mix in that watery bit right at the surface, which makes a significant difference in the thickness and movement of the glaze layer...
- Pyewackette and Rae Reich
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Hydrogen peroxide
"...most common peroxide is hydrogen peroxide (H2O2), colloquially known simply as 'peroxide'."
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Hi Mel,
Welcome to the Forum!
You might have the piece appraised before starting restoration work?
Any road, even the new paint removers* do a decent job of softening old paint to the point where it lifts off and/or liquifies somewhat.
It might take several applications and some time; even then, the paint may have discolored the clay, and the agitation necessary to remove the paint may damage the clay.Spot test before going all in!
*The newer products don't work as quickly, however, they are less toxic.
Even so, adequate ventilation, gloves, eye protection and organic vapor respirator (with new cartridges)...
Beware, the paint may contain lead!- Rae Reich, Min and Bill Kielb
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+ Kelly's suggestion for other clay(s), particularly if your vendor(s) can point to a clay they know crazes less than the one(s) you're using.
In my craze journey, that's what happened! I'd scrapped several recipes, started over, re-formulated - getting closer, larger pattern - then went with a different white stoneware, problem solved.- Julie_R and Kelly in AK
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Hi Phyllis,
Welcome to the Forum!
I've deleted the duplicate post; next, I'll move this post to Equipment and Repair sub-forum.
...err, another Mod already moved it! -
Hi Kathryn,
Welcome to the Forum!
Good questions.
Given a good glaze fit (no crazing), some adjustments could be made to induce crazing, which would likely start with a few cracks where the glaze is thickest and where there is more stress - a wide pattern*.However, making adjustments is more straightforward when the glaze recipe/formula is available, so, broadly speaking, adjustment can be made while other glaze qualities remain fairly constant - when it melts, how glossy, how much it sags/runs, color, et cetera...
I'm curious to see further discussion on the topics!
*In the other direction, eliminating crazing, if the craze pattern is large (just a few cracks), adjustment to a good fit might be possible, however, if the craze pattern is fine/small, the required adjustment may be out of reach...
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New and former Studios, cement slab flooring.
I'm wearing crepe sole mid-high work boots when it's cold, somewhat supportive flip flops (Sperry Top-Sider) when it's hot, slip-ons with groovy insoles when it's medium.
I work more sitting than standing. I get purple toe (Raynaud's) fairly easily, so keeping the feet happy is important for me. Wool socks, an extra layer at the ankle (cut off the feet part of worn socks, voila! ankle warmers), watch cap (warm head->warm hands and feet, try it), and insulated foot pedal all help.Yep, the heavy cast alloy foot pedal draws off A LOT of heat! I've taped a layer of bubble wrap to the foot pedal, voila ii! right foot gets much less mad ever since.
I'm having pain in the L 4-5, a bit better yesterday, much better today.
Hope you are feeling better soon Min.
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i) Motor well protected from corrosive kiln atmosphere
ii) Adjustable plenum
If you are considering moving your vent setup to a larger kiln in future, choosing a "stronger" fan for your 1.4 cubic foot kiln may make sense*.I bought an inexpensive inline 100 cfm motor for my setup. It's strong enough to pull a stream of superheated atmosphere from my 7 cubic foot kiln and is still working fine after a few dozen bisque and glaze firings. When it fails, I'll look at replacements that do not have the motor hanging in the vent stream! Although the superheated and no doubt rather corrosive stream of kiln atmosphere is mixed with ambient air in the plenum (the box fitted against the kiln), it is still corrosive enough to wear away unprotected and/or susceptible materials...
*the stronger the fan pulls, the greater/larger the ambient port in the plenum "should" be?
I'm saying yes.
An adjustable ambient port (aka "bypass" port) in the plenum allows for ...adjustment!
A stronger fan allows for more dilution of kiln atmosphere and sizing up in future.Added: Reasonable trade off between suitability, quiet, long-lasting, price, likely looking at well over a hundred US dollars.
Added II: This might be a starting point
Jabsco 35115-7020
Searching that ^ string will generate related hits. Note the flange specs.
Max inlet and ambient temps, ah, that might be a red flag.Added III: Jabsco 35515-0010 max inlet temp is higher, 130°F
Added IV: both Jabsco models, above, turn a fan in the vent stream, however, the motor does not. The commercial solutions I see use similar fans...
When my cheap inline freezes up, I'll be shopping! -
Good question Greg.
I'm sorry I don't have an answer.Storage where the wares aren't visible can be more challenging. heh.
Ah, Callie's post just came in! Good questions.
I'll add, when and why will you be taking wares out of storage (an extension of Callie's first question), and how many (one, a set, a representative sampling, ?) at a time?
Marking the containers with strings* that correspond to files** might streamline the process, cutting out printing and affixing images.
Mainly I just wanted to bump your thread...
A way to get rid of ware, err, make room for new wares ...has to be part of the plan!
*string - names! Your naming convention(s) could be descriptive/helpful?
Whatever is important to you could be included (within reason, err, up to a point), class/shape, size, clay, glaze, pattern, date...
e.g. six inch bowl, red clay, Clear Blue glaze, 2022, A1 "grade" - B6RCB22A1
...I'd think about naming conventions for a long while afore committing...
Containers having a similar class/shape of wares, from a particular era, finished similarly, could cut down on searching.**files
images, renamed to match the ware names
text file, sortable might be handy, so spreadsheet, perhaps a line entry for each ware, where each line has columns for any data you might want to sort/search on... -
Hi Ann,
Welcome to the Forum!
You might check with Skutt.
Their support is very responsive and helpful - when I had questions, a real (nice) person answered the phone.
Check their hours...I had a year model 1983 1027 for several years.
As I recall, the sections lift apart.
They connect electrically via plugs -between the red boxes - which you will see when the segments are separated.
I'm not sure if your kiln is older or younger.
Skutt has some older manuals available via their website; try this one?
KilnSitter - Kilns | Ceramic Pottery Kiln, Glass Kiln, Pottery Wheels | Skutt -
Resource favs:
Tony Hansen's site, a treasure of detailed info; here's the articles list Ceramics Technical Articles (digitalfire.com)
See also blog, recipes, glossary...This Forum!
Note, any closed/archived discussion topic isn't included when using the internal search feature*.Susen Peterson's book, The Craft and Art of Clay
Functional smoke detector(s), fire extinguishers;
Kiln glasses;
Be home any time the kiln is over 452°F (or so)...*"External" search, from your favorite search engine casts a wider net; try including https://community.ceramicartsdaily.org/ in your search string, e.g.
https://community.ceramicartsdaily.org and Hulk and "kiln schedule"will return open and closed topics...
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Cobalt is cheaper today than it was ~five years ago.
Hope petalite price drops, still $10/lb (or more)... -
Second seven cubic foot electric has been test fired to cone 5 (first bisque later this week maybe); it's brand-new touch screen three zone Bartlett/Genesis controlled*.
I fire to cone 5, oxy with downdraft fan, 100°F drop and hold after peak, controlled drop to 1850°F with fan on, then all off.First kiln was a manual, three segments, each with Low/Medium/High switch.
Initially, I watched cone packs through the peeps; later on, I checked cone packs afterwards and just watched the pyrometer during.
I set the sitter with +1 small cone - which almost always dropped at about the right time - for a safety backup.
I'd kept notes on each firing - times, temps, cone packs, results - which I'm poring over now, for upcoming firings in the new kiln...I was so sure that gas was the only way to go!
However, there just wasn't a place to set one up at our last house (there isn't a place at our new house either); I'm happy with electric.
Both power sources have shot up in cost over the last several years. We have enough solar here to run everything and then some - new system went online last month - that helps a lot.*Per others' shared experiences, I'll be closely monitoring cone packs as the kiln reaches target! ...for the first several firings.
Looks like the new kiln's pyrometers read ~35°F lower than my portable; although the portable very likely reads the same as before, I'll be watching a cone pack through the peeps!
...with appropriate kiln glasses on, o' course, against harmful rays any any flying bits... and make adjustments from there.Everyone I've spoken with that has gone from fully manual to full auto loves the clickety-clicks.
I love the clickety-clicks as well! -
I'm using several of the profiles depicted*!
For more vertical lidded jars, something like #1;
bowls, generally like 2 and 3;
for drinking - glasses, mugs, tumblers, cups, etc., something like #4,5,6, where the recurve is slighter, but perceptible when the eye is level with the rimAn elderly gentleman's son asked about designing a bowl that would assist his father in loading his spoon, so, the "helper bowl" - where the wall curves in somewhat at the top, which isn't particularly helpful when one tips the bowl up to drink from, but it does help with loading the spoon ...and guarding against spills.
Several variations of lidded forms have a more severe incurve, e.g. the teapot.In general,
trying "work" the rim only as much as necessary, this from trying to limit the bumpy/gritty feel that sanded/grogged clays exhibit when the finer particles have been worn/washed away;
encourage accumulation of slip on the rim - leaving a bead of slip when ribbing off the outside, same when sponging out then smoothing up the inside;
definitely distributing the slip evenly (somewhat) with the chamois as a final step on the rim proper**;
smooth the rim of slip on the inside with a fingertip and move the pull-off mark down a centimeter or two;
smooth and shape the outside just below and up to the rim with a frosting spatula;
use the same spatula to reduce the rim of slip into a spiraled tool mark;
post bisque, sand any burrs smooth***;
after pour in/out of liner glaze, dip the rim to accumulate a thicker layer of glaze on and just below (on the inside) the rim****;
wax, cut, and sponge the liner to outside glaze transition (per Tony Hansen's "Liner Glaze" article and video clip).
Raw wares:
The frosting spatula which is a favorite tool. It was used here to smooth and shape the outside wall just below the lip.
That's where the lip "parks" - a critical surface, imo.
In the case there's a ridge of slip at the bottom of the arc, I'll use the spatula to form a diminishing spiral down the side.
Wow, the camera "sees" more that I do! The rim treated thus will usually hold a nice bead of glaze.
Here there was a rim of slip below the rim band, hence the diminishing spiral ...which matches another bowl from yesterday's session.
*Currently; there's been some evolution - there may yet be more.
**A potter named Adam makes the point in one of his YouTube clips that the chamois merely distributes ("...dispersing that damp clay...") slip; to smooth, burnish, "compress" and/or tool the clay, he uses a strip of plastic bag, which removes the slip and smooths the rim. Perhaps leaving the slip does weaken the rim? idk
***outside, with shop vac and mask for me, buckets of rinse water, time, sun, and wind for the wares
****even the stiffest glazes seem to move down a bit, especially at the rim -
Interesting! Thanks to all contributing to this thread.
My guess, given the amount of Boron in my glazes (that contain MgO), the MgO is (likely) all melting, early, per the previously mentioned eutectic.
However, fully melted may not necessarily mean "active flux" as in lowering the melting point of Silica and Alumina.I'm still reading "refractory" as not melting/melted.
Words!
From "DOE Explains" article, "A catalyst is a substance that speeds up a chemical reaction, or lowers the temperature or pressure needed to start one, without itself being consumed during the reaction."
Chlorophyll (green in plants) is certainly the first catalyst I'd heard of; the bead coatings in catalytic converters also comes to mind - cars were being fitted with them some forty-eight years ago...The term "flux" as used in ceramics/pottery for glaze, clay, etc. may be different from the worlds of metal - soldering, brazing, welding, smelting.
...err, certainly is different! Wikipedia has a nice long article on Ceramic Flux; MgO is listed.
The term in medicine (never mind!), math, physics, general state/status, magnetics/electrics - and more! - each somewhat distinct.
Michael G Parry Thomas
in Equipment Use and Repair
Posted · Edited by Hulk
instrument in use
Thanks for sharing Michael!
I'm noting and adjusting glaze specific gravity, then adjusting thixotropy as required, such that revolving mass of glaze in the bucket* comes to a stop and "bounces back" a bit after three to four revolutions once stirring ceases.
Tony Hansen's articles and video clip on the subject changed glazing for me!
Thixotropy (digitalfire.com)
* I'm stirring with a kitchen whisk, at about one second per turn
Added - Anderen Limited has a video clip of a torsion viscometer in action (I was curious about how they are used), try this search string:
"Gallenkamp type" Torsion Viscometer