tag:blogger.com,1999:blog-65358894390702443252024-03-19T09:49:40.816+00:00Glass Tips from VerrierInformation on stained glass, fusing, kilnforming and glass working Stephen Richardhttp://www.blogger.com/profile/17854964450984329333noreply@blogger.comBlogger1210125tag:blogger.com,1999:blog-6535889439070244325.post-34945706519047255662024-03-13T07:00:00.055+00:002024-03-13T07:00:00.135+00:00Heat Up vs AnnealingI am amazed by the effort put into
ramp up rates, bubble squeezes, and top temperatures in comparison to
annealing. The emphasis on social media groups
seems to be to get the right ramp rates for tack fuses and slumps, bubble squeezes,
etc. Most of the attention is on the way
up to processing temperature.The treatment of annealing and
cooling is almost cavalier by comparison. Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144883 -4.284677227.504254463821155 -39.4409272 84.124722136178846 30.8715728tag:blogger.com,1999:blog-6535889439070244325.post-48164373741462544602024-03-06T07:00:00.055+00:002024-03-06T07:00:00.149+00:00Slumping StrategyA schedule was
presented for a slumping problem of a 6mm/0.25” blank. It consisted of three segments each of a rate
of 277C/500F with short holds up to 399C/750F and then a rapid rise to 745C/1375F.
The cool was done with two long holds at
537C/1000F and 482C/900F followed by cooling rates for 12mm/0.5”
My response was
that, yes it was fired too high. Not
only that, but the Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144883 -4.284677227.504254463821155 -39.4409272 84.124722136178846 30.8715728tag:blogger.com,1999:blog-6535889439070244325.post-39835978222774116042024-03-03T07:00:00.001+00:002024-03-03T07:00:00.138+00:00Using Glass for Passivation in Semiconductor Applications Robotic arm holding a silicon wafer for semiconductor processing. Image source: iStock.A blog post by Krista Grayson of Mo-Sci raysonIn the fast-paced world of semiconductor manufacturing, where precision and reliability are paramount, choosing a suitable passivation material is critical to ensuring the optimal performance of electronic devices. Among the library of viable materials, Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663399999998627.504249963821152 -39.4409134 84.124717636178843 30.8715866tag:blogger.com,1999:blog-6535889439070244325.post-60253037164152470142024-02-28T07:00:00.127+00:002024-02-28T07:00:00.131+00:00Refiring and AnnealingA question about re-fusing:
I have just
taken a large piece, with uneven layers out of the kiln, it went in … and fired
for double thickness. A small piece has flipped and is showing the white side. …
If I cover this with a thin layer of coloured powder frit, does the piece need
the long anneal process when I fire it again, please. I will be taking it up to
the lowest tack fuse temperatureStephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0tag:blogger.com,1999:blog-6535889439070244325.post-91857706340265777842024-02-21T07:00:00.020+00:002024-02-21T07:00:00.154+00:00Go-to Schedules It’s a schedule I always use.
This is a frequent statement
in response to a firing that has gone wrong.
You don't always
fuse the same thing, or the same design, or the same thickness, etc. So why always
use the same schedule?
The schedule for the
firing each piece needs to be assessed individually. It may be similar to
previous firings. But it may have differences. Assess what those Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-74982842408971300312024-02-14T07:00:00.072+00:002024-02-14T07:00:00.215+00:00Differential Cooling of Transparent and Opalescent GlassA statement was
made on a Facebook group that transparent glass absorbs more heat than
opalescent glass. And it releases more heat during cooling. The poster may have
meant that the transparent heats more quickly than the opalescent, and cools
more quickly.
Yes, dark transparent
glass absorbs heat quicker than most opalescent (marginally), and it releases the
heat more quickly (again marginally)Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-45775549912447336962024-02-07T07:00:00.035+00:002024-02-07T07:00:00.326+00:00Comparison of Citric Acid and Trisodium Citrate.These two substances
are useful means of removing kiln wash and refractory mould material from
glass. They are important where abrasive methods such as sand blasting are not
available or appropriate.
My recent
experience with both citric acid and trisodium citrate shows differences in
performance. This makes each more suitable in different contexts.credit: Amazon
Trisodium
citrate is the safestStephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com2Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-75181110293324662692024-01-31T07:00:00.047+00:002024-01-31T07:00:00.138+00:00Care of Ceramic Kiln ShelvesMullite kiln shelvescredit: IPS Ceramics
The most popular and easily available ceramic shelves are made
from Mullite, Cordierite, and CoreLite. Other hard specialist kiln shelves are
available. They are made of other materials. Shelves are also made from other
materials such as refractory fibre board, vermiculite, and fire-resistant
ceiling tiles. This concentrates on the care of ceramic shelvesStephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144883 -4.284677227.504254463821155 -39.4409272 84.124722136178846 30.8715728tag:blogger.com,1999:blog-6535889439070244325.post-42549120418264247972024-01-24T07:00:00.009+00:002024-02-04T20:58:35.390+00:00Thickness of Powder Application
Why does my powder disappear when I
fire?
Powder may appear
to disappear after firing as Donna Brown found out with the pieces of her work
shown here. Glass powder is finely ground glass sheet. The full colour of glass
sheet is seen only when the glass is 3mm thick. So, to get the same intensity
of colour you need to have the powder nearly 3mm thick.This image shows the powder Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-19126385761121270882024-01-17T07:00:00.087+00:002024-01-17T07:00:00.324+00:00Mending a crack I had a piece
crack due to an annealing oops. I put powder on it and put it back in at a
higher temp with a much longer anneal time. It looks great on the front, but I
can still see where the crack was on the back. Is it supposed to be like that?
I didn't think to put powder on that side.
If you think about
why you get crisp lines at the bottom of a strip construction and a more fluid
Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-75865344786670756022024-01-10T07:00:00.012+00:002024-01-10T07:00:00.286+00:00Identification of Mechanical and Thermal StressThe Identification of stress is important in investigating the
causes of stress. We have well established clues to help us with our glass
selection and alteration of our firing schedules. We can get more information about
why the cold glass has broken from the scientific literature. The manufacturers
of float glass and the installers of large panes investigate thoroughly the
causes of breaks in Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-14481009854029804422024-01-03T07:00:00.037+00:002024-01-03T07:00:00.136+00:00Stainless Steel Stringer PotsCredit: Paul Gardner httpswww.facebook.com It is a
consideration in stringer and murrini work that the pot be re-usable. This has
led to the development of stainless steel square pots. The thorough cleaning of these is difficult
even with a lot of banging. Containers with removal bases have been developed
as a result.
The
importance of a container with an integrated bottom is toStephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144883 -4.284677223.797176511646519 -39.4409272 87.831800088353475 30.8715728tag:blogger.com,1999:blog-6535889439070244325.post-49899034490322058652023-12-27T17:41:00.001+00:002023-12-29T01:01:17.090+00:00Scheduling with the Bullseye Annealing ChartThis
post is about adapting the Bullseye chart Annealing Thick Slabs to write a schedule for any soda lime glass as used in kilnforming.I frequently
recommend that people should use the Bullseye chart for Annealing Thick Slabs in Celsius and Fahrenheit. This chart applies
to glass from 6mm to 200mm (0.25” to 8”).“Why should the Bullseye annealing chart be used instead of Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663235.67113345579822 -39.4409132 75.957834144201769 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-33462907945572604702023-12-20T07:00:00.050+00:002023-12-20T07:00:00.134+00:00Anneal and Cool RelationshipAnnealing and
cooling are directly related. You cannot extend the anneal soak without also
slowing the cooling rates and expect to have a sound piece. What I am
seeing on the internet groups about annealing breaks is comments saying the
anneal soak is not long enough. So, people add time to the hold at the
annealing temperature and still get breaks. They get breaks because the cooling
rates are Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663235.67113345579822 -39.4409132 75.957834144201769 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-35520285923449080312023-12-13T07:00:00.026+00:002023-12-13T07:00:00.200+00:00Fold Moulds
These moulds are
available in stainless steel forms in various sizes
You can create your
own mould for self-supporting display items. Fibre board and vermiculite board
are suitable.
I chose 25mm/1”
fibre board because I had a suitable piece lying around. It is possible to use
thinner fibre board, but the thicker board is more likely to resist deformation
over a long use periodStephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-84125317837174865732023-12-10T09:10:00.020+00:002023-12-10T09:10:00.141+00:00Sealing MEMS Devices with Glass Krista Grayson•December 5, 2023Micro-electromechanical systems (MEMS) have revolutionized various industries by integrating miniaturized mechanical and electrical components onto a single substrate, enabling the creation of highly sensitive and efficient devices. They are key elements in an array of medical, automotive, industrial, and defense applications.aHowever, the success of MEMS Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144883 -4.284677227.504254463821155 -39.4409272 84.124722136178846 30.8715728tag:blogger.com,1999:blog-6535889439070244325.post-90073635380772291382023-12-06T07:00:00.053+00:002023-12-06T07:35:58.476+00:00Dog Boning During SlumpingDoes the size of the rim affect the amount of dog boning
when slumping rectangular items?
This question was prompted by previous testing on the amount
of distortion by adding additional elements. I found that single layer pieces
stacked 15mm/0.6” or more from the edge do not affect its shape.
This led me to think: “how wide a rim would be required to
avoid dog boning of rectangular pieces whileStephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144883 -4.284677227.504254463821155 -39.4409272 84.124722136178846 30.8715728tag:blogger.com,1999:blog-6535889439070244325.post-57538788755870103692023-11-29T07:00:00.131+00:002023-11-29T07:00:00.140+00:00Stuck Kiln Wash Moulds
Kiln wash on ceramic moulds lasts a very long time. But
sometimes you want to use a different separator. First you need to prepare
yourself and the area for the process.
Preparation
It is best to wear a mask while
removing kiln wash or other separators to reduce the amount of dust you inhale.
Wearing an apron or other outer wear will keep the dust off your clothing.
Spread a Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-37222783359929148482023-11-22T07:00:00.107+00:002023-11-22T09:53:56.919+00:00Slumping Schedules When slumping fired pieces, it is most often appropriate to
use a slow ramp rate to avoid too rapid expansion of the glass that might lead
to a break. Most glass breaks on the ramp up are below 300°C/573°F. It is in
this range that there is a rapid expansion of ceramic. This means a slow rate
is protective for both glass and ceramic moulds.
Slumping Schedules by Profile (Celsius)
Flat Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0tag:blogger.com,1999:blog-6535889439070244325.post-70514812775681479552023-11-15T10:27:00.091+00:002023-11-15T10:27:00.138+00:00Inadequate Annealing - Effects on Next FiringCredit:https://immermanglass.com/about-kilnforming/cracks/The speculation
about breaks caused by inadequate annealing of the piece on the previous firing
is common. I do not know if this can be proved to be inaccurate, but we should think about it.
A parallel
condition to this poor annealing is toughened/tempered glass which is under a lot of stress between
the inside and outside Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-33450347549603711672023-11-08T07:00:00.026+00:002023-11-08T07:00:00.147+00:00Steel MouldsCredit: Slump and FuseDo steel moulds need to be kiln washed for slumping?
Some prominent people in the
kilnforming milieu like to promote the extremes of the craft. The argument
seems to be that the glass does not get hot enough to stick to the metal at
slumping temperatures. It could be argued in the same way that it is possible
to slump glass on bronze or unglazed ceramic moulds.
This Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-55956605443339045692023-11-01T07:00:00.070+00:002023-11-01T07:00:00.251+00:00Refiring and AnnealingA question
about re-fusing was posted:
I
have just taken a large [rounded tack] piece, with … A small piece … flipped
and showing the white side…. If I cover this with a thin layer of coloured
powder frit, does the piece need the long anneal process when I fire it again...
I will be taking it up to the lowest tack fuse temperature possible, so the
rest doesn’t change too much.
When Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-33176590019446923112023-10-25T07:00:00.055+01:002023-10-25T07:00:00.157+01:00Spikes on Frit CastingsCredit: The Crucible.comIt is frequent to have castings from frit with spikes, needles,
or prickles around the edges.
Causes
These spikes result from the glass touching the edge of the
mould or separator during the hottest part of the firing. The glass particles first begin to compact as the glass rises toward the fusing temperatures. As the
temperature increases toward the casting Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663235.67113345579822 -39.4409132 75.957834144201769 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-25328795016212681212023-10-18T07:00:00.078+01:002023-10-18T07:18:45.995+01:00Long Anneal SoaksCredit: Bullseye https://www.youtube.com/watch?v=-8hK9KlprvcLong anneal times seem
to be becoming popular. At least they are being recommended frequently by
people in Facebook groups. They are recommending very long anneals to solve
stress and breakage problems.
Are they effective?
This Bullseye video on some results from annealing research shows (at 13:00 minutes)
that excessively Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0Verrier55.8144838 -4.284663227.504249963821152 -39.4409132 84.124717636178843 30.8715868tag:blogger.com,1999:blog-6535889439070244325.post-90671530895055994442023-10-11T07:00:00.036+01:002023-10-11T07:00:00.193+01:00 Prevention of Spikes at Corners Often, after fusing rectangles we are left with sharp points at the
corners. How can we prevent it?
Nipping corners off rectangles, especially opalescent and the underlying
base pieces, is a standard practice to avoid sharp points on corners of a finished
piece.
The principles of this relate to how glass contracts when cooling.
The glass expands in the fusing and then contracts on Stephen Richardhttp://www.blogger.com/profile/18043440528649354154noreply@blogger.com0