Hulk
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Images from this week's glazing.
I'll charge up the "real" camera for next.
There's just enough light in the Studio for working at the wheel, but not so much at the workbench and glazing table*.
Bowl, where liner glaze has been poured in, then (carefully, somewhat slowly, two or three turns) swirled about so there's glaze right up to the edge, then poured out, wait, wait, then, holding the bowl upside down, dip the edge.
At about two o'clock, there's slight overlap ridge, which past experience says will be almost imperceptible on this white stoneware.
Mug, where liner glaze has been poured in, then poured out.
I try to grasp the mug the same way each time; pouring past the handle is almost last, where the angle is greater/greatest and hence the handle doesn't get tagged.
The leading edge of the pour comes around, then follows the initial trailing edge, leaving a fairly uniform coating.
A full "wind up" of the lower arm almost does it; I grasp with the right, steady with the left, then shuffle the grip just afore the end, where the rotation is slowEst.
After outpour, wait, wait, then dip the edge, run the drip around and around, wet a finger and smooth any drips when they are still shiny wet, but the surrounding glaze layer is losing its sheen. A smoothed drip is visible here; again, past experience says it'll be fine.
The top of the handle often gets a kiss of glaze when the rim is dipped - typically I'll just leave it there.
Liner glazed jars have been waxed on the rim and down the inside ~3/4"
From there, I run a razor knife around the rim and sponge away remaining liner glaze (credit Tony Hansen's article and video clip on liner glazing).
The chattery marks are filled with glaze or underglaze, which provides some highlight/contrast and to ensure the cuts are wetted with glaze all the way to the bottom.Aiming for a thicker layer of glaze on and just below the rim, as that's where it seems to thin the most, gravity...
Next, outside glazing!
*Picked up a hanging LED shoplight yesterday, that should help.
The pending remodel to include flush mount LED fixtures in the ceiling... -
I've seen some thrown tube handles that work.
...also pulling and then cutting handles "off the hump" where the initial taper is thrown, then the wheel is stopped for the pulls...
...haven't tried either, but thrown tubes for side handled teapots is "on the list."
Back to Michael's extruder, nice use of hydraulic, thanks again for sharing!
Please do report back on how it's working for you, any helpful tips, et cetera... -
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I'm curious, would a stationary polishing tool - where the hands are, therefore, holding the piece to be polished - be a consideration?
Perhaps a bench unit; they look like a grinder, but have more room around the driven portions...Guessing, the polishing is done using cream/liquid and a soft pad of some sort?
Any road, ten cfm (cubic feet per minute) - supplying and using that much compressed air likely generates significant sound pressure - quality ear protection!
added: nice work!
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There are several varieties of grit, e.g. oyster shell, granite, "high magnesium" limestone...
Each may have a different influence on your work. -
Wasn't particularly happy with the battery powered tools I bought some thirty years ago.
However, "big" projects* drove decision to wade back into cordless, so many positives!
Lightweight, powerful, long battery life, precise control at low speed, cute little light that shines on the target, easy to use on a ladder...
...also very handy for stirring up glazes - no cord knocking over coffee, wares - and that precise control, woops, heh, just kidding, no, really, check that the trigger has the feel/control you need.
The chuck is awesome - just that is so worthwhile.
It's no substitute for the burly half inch corded model when it comes to mixing reclaim, no.Add a hammer drill to the stable?
Yep! Hammer drill makes putting holes in concrete/stone so much easier, sooo much.
Add an oscillating tool? Why did we not have one of these a'ready? O M G what a handy tool.
...the batteries are all interchangeable, go.
Added: The batteries on our three yellow branded tools are completely interchangeable.
The three amp/hour one is heavier, but lasts longer, eh?All three have already "earned" back the costs, imo, after their first jobs.
Another tool I put in that same class, pancake/portable compressor and finish nail gun; compared to setting nails in baseboard and door casing By Hand?
We've since added a framing nail gun and upholstery staple gun.I'll be quiet now!
*Remodeling the son's house, where we're often using every drill motor we own, each fitted with a different bit/drill, go!
The aforementioned (yellow) brand markets a very short body lightweight cordless, handy for drilling wire ways through wall studs, makes a long day of hanging sheetrock a bit less onerous - light, powerful, and, And, precise control for those of us that prefer screws to nails (without investing in a drywall screw gun).Added II: Note, a "driver" hammers in the turning direction, which assists in driving screws; a "hammer" drill impacts straight ahead, which helps when drilling, particularly where the material doesn't cut into chips when drilled, e.g. cement, stone
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I'm reading Seesee's problem description as: there's a thickening where the slip drains out of the mold, which causes the deformation.
Any chance the mold can be rotated whilst draining the slip?
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Mostly pour in/out and dip.
A bit of brushing to fill chatter marks, touch up spots, and decorative marking; ear syringe for filling and then sucking out hollow knobs; squeeze bottle for glazing inside foot rings and squirt pour the outside of ware too big to dip!Planning to do some glazing this week, will circle back with images...
I've done some spraying when attending Wheel I and Wheel II at the (previously) local JC Ceramic lab; not set up to spray at home just yet, and IF/when I am, it will be for effect, not main glazing procedure...
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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
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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!- Bill Kielb, Rae Reich and Min
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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...
Venting a small electric kiln
in Equipment Use and Repair
Posted
Hi Amy,
Welcome to the Forum!
Good question.
My opinion, kiln venting breaks down to
i) direct, where a small stream of superheated kiln atmosphere is sucked through small holes (typically in the kiln floor), mixed with ambient air, and routed outside via a 4 or 6 inch vent, or
ii) overhead, where a hood pulls air from above the kiln and routs it outside via a 6 or 8 inch vent
Furthermore (my opinion, observation and experience), option i doesn't get all the fumes out of the area/room but does a better job of removing moisture and caustic fumes from the kiln.
I ended up doing both for my first kiln setup - direct powered vent AND an overhead vent - then I felt comfortable being in the Studio while the kiln was firing.
My current setup is on the protected porch - no connection to indoors - where I'm using the direct vent only.
Either way, provision for "make up" air, that's essential (for any enclosed area)! There must be a clear path for air to enter the area, to make up for what is being expelled.
More
Kiln Venting - The Ceramic Shop
Kiln venting system (digitalfire.com)
Kiln Vent Guide: How and Why to Vent Your Kiln (ceramicartsnetwork.org)