mel jacobson on tue 17 oct 06
i have been thinking all week that
when you score and slip you
produce both chemical and mechanical bonding.
is that correct?
that is what the sugar and vinegar does.
and, magic water.
esp with porcelain. chemical bonding..not glue, but bonding?
and, i mentioned lana wilson in my first post
on spooze.
mel
from: mel/minnetonka.mn.usa
website: http://www.visi.com/~melpots/
Clayart page link: http://www.visi.com/~melpots/clayart.html
pdp1@EARTHLINK.NET on tue 17 oct 06
Hi Mel, all,
Historically, Glues were always close cousins to
Paints, and both of them, if they were to work at
all, actualkly work(ed) in the basis of a
successful Chemical bonding, with only some
approximate mechanical bonding...with the latter
contributing very little to the actual strength of
the outcome.
Really, as far as I recall, adhesive bonding as
such, of any kind, ( aside from the occurance of a
Vaccuum, or matters of friction, or functions of
viscosity, ) is Chemical in Nature, and not
mechanical except as an incidental.
Love,
Phil
in chilly el Vee
----- Original Message -----
From: "mel jacobson"
(snip)
> is that correct?
> that is what the sugar and vinegar does.
> and, magic water.
> esp with porcelain. chemical bonding..not glue,
but bonding?
> mel
>
> from: mel/minnetonka.mn.usa
> website: http://www.visi.com/~melpots/
Ivor and Olive Lewis on wed 18 oct 06
Dear Mel,
I think you are tuning in to my wavelength. Electrons provide that =
bonding force. But water gives a double dose of bond because the =
Hydrogen atoms provide the opposite polarity. You should buy yourself a =
copy of General Chemistry by Linus Pauling. Less that $20 US for first =
year undergrad chemistry. Low priced knowledge ! ! Section 12-4, p 428 =
covers the Hydrogen Bond and some of the mysteries of Ice and Water
One thing that I forgot to say in my post of yesterday is that if you =
are scoring shallow grooves which have entry angles of about 45 deg you =
increase the area of the joint by fifty percent, that means one and a =
half times the area is contributing to the adhering area.
I think there may analogies to the general principles of metal welding =
and you Mel have that knowledge because you have done the college =
courses. Using good slip is like soldering. NO filler, just a thin film =
that blends with both surfaces. With metals an intermetallic alloy forms =
(Chemistry for Phil in El Ve) that is compatible to both metals. But =
with clay the composition is constant across the boundary. I am sure =
that the wetter the slip with high water to solids ratio, the weaker the =
junction, the greater the shrinkage, even if it is less than a =
millimetre, and the greater the chance of drying cracks.
I am not sure about Spooze, never used it. Does the Corn syrup =
crystallise in the joints ? or is it acitng like a film of solder that =
alloys to both surfaces?
Phil may have something in suggesting that adhesives work chemically. =
But that implies some sort of chemical reaction and I do not think =
Acetic acid reacts with Glucose syrup or that either react with Clay. So =
I am wondering what the processes are when Spouse is being used.
Thinking about what William Schran is saying, quality control of the =
slip may be essential and selected to conform to the nature of the clay =
being joined.
The suggestion of Randy Moody can be tested if a slip is used that has a =
differing colour to the base clay, or it could be could be stained. =
Examination of cut sections with a high power lens might reveal fissures =
as small as ten microns wide given sufficient optical contrast.
One final thing, does anyone know how "Sticking Up" is done in the big =
factories where production is automated. Or do they employ Lutefish to =
do it ? ? ?
Thank you everyone who has contributed to this thread.
Best regards,
Ivor Lewis.
Redhill,
South Australia.
Richard Aerni on wed 18 oct 06
Ivor,
Sorry that I haven't had the opportunity to respond to your reply to my
posting defending scoring and slipping for sectional pieces. I guess my
excuse would be spending marathon hours in the studio and simply being too
tired when arriving home at the computer to deal with it. But you deserve a
good reply.
Let me first say that I wouldn't choose to argue science with you, as you
appear to be so thoroughly grounded and I'm more of a seat-of-the-pants
science guy...just enough knowledge to be dangerous! And you are probably
right when you describe the bonding process. But this is kind of like
arguing the difference between using a titania-red iron blend in glazes in
place of rutile with Ron Roy or John Hesselberth...theoretically it should
work perfectly well, but in actual practice (in my studio) there are
significant differences. I tend to go with what works in my work, and that
is derived from a basic theoretical knowledge, tempered by practical
experience.
In my studio I join pieces in various ways. Some are stacked immediately
upon being thrown, and for these I take the fewest precautions...mostly I
just angle the joints so that the bottom one is banked like the curve on a
racetrack, so that I can counter centrifugal force in a small way. For
larger pieces, with more at stake, I also use the serrated rib, which as you
point out, gives about 50% more surface with which the other piece can
interact. When the pieces have sat for more than a few minutes before
joining, I also slip them after scoring, using a slip made from the clay
body which has been decanted multiple times so that it's consistency is just
slightly creamier than toothpaste from the tube. I have played around with
both deflocculated and flocculated slips in this regard, but tend to go with
what is simplest and gives the best results. I do floc and defloc slips for
use over the pieces later on. And, I tend to pay a lot of attention to
their consistency and mesh size. For joining leatherhard pieces, I
carefully score and slip both sides of the joint and try for a perfect fit.
It's interesting to note how we must go about our work. I sense that you
work from a sound basis in scientific knowledge and then proceed in a way
that makes what should happen, happen in your studio. I tend to go about
things in the way I have either been taught or noodled through on my own,
until there is a problem, when I try to work through to a practical
solution, using a half-baked imitation of the scientific method (analysis
followed by testing, eliminating one variable in each test while keeping the
others as constant as possible). When I find something that works, I try to
figure out why it worked, but the why is much less important than the fact
that it works. It's not that I'm not interested in the truth, it's more
that I rely upon my production and sales in order to eat and pay the rent,
and have to go with what works best in that equation. Which doesn't mean
that I don't pay attention to science, but I'm not a scientist. I inhabit a
land somewhere between the realms of pure art and pure science, and I am
comfortable there.
I love reading your posts because they almost always teach me something, if
not sceince, then a scientific response to a problem, and if not that, then
simply your wonderful sense of restraint in replying to a post. I don't
think we have any argument in this matter, and I was simply responding to
your posting about the importance of chemical bonding and the misplaced need
to score, with my own practical experience.
So, I am not defending my position with science, but with an excuse of
practical expediency.
Happy potting to you!
Best,
Richard Aerni
Rochester, NY
On Wed, 18 Oct 2006 17:24:50 +0930, Ivor and Olive Lewis
wrote:
>Dear Mel,
>I think you are tuning in to my wavelength. Electrons provide that bonding
force. But water gives a double dose of bond because the Hydrogen atoms
provide the opposite polarity. You should buy yourself a copy of General
Chemistry by Linus Pauling. Less that $20 US for first year undergrad
chemistry. Low priced knowledge ! ! Section 12-4, p 428 covers the Hydrogen
Bond and some of the mysteries of Ice and Water
>One thing that I forgot to say in my post of yesterday is that if you are
scoring shallow grooves which have entry angles of about 45 deg you increase
the area of the joint by fifty percent, that means one and a half times the
area is contributing to the adhering area.
>I think there may analogies to the general principles of metal welding and
you Mel have that knowledge because you have done the college courses. Using
good slip is like soldering. NO filler, just a thin film that blends with
both surfaces. With metals an intermetallic alloy forms (Chemistry for Phil
in El Ve) that is compatible to both metals. But with clay the composition
is constant across the boundary. I am sure that the wetter the slip with
high water to solids ratio, the weaker the junction, the greater the
shrinkage, even if it is less than a millimetre, and the greater the chance
of drying cracks.
>I am not sure about Spooze, never used it. Does the Corn syrup crystallise
in the joints ? or is it acitng like a film of solder that alloys to both
surfaces?
>Phil may have something in suggesting that adhesives work chemically. But
that implies some sort of chemical reaction and I do not think Acetic acid
reacts with Glucose syrup or that either react with Clay. So I am wondering
what the processes are when Spouse is being used.
>Thinking about what William Schran is saying, quality control of the slip
may be essential and selected to conform to the nature of the clay being joined.
>The suggestion of Randy Moody can be tested if a slip is used that has a
differing colour to the base clay, or it could be could be stained.
Examination of cut sections with a high power lens might reveal fissures as
small as ten microns wide given sufficient optical contrast.
>One final thing, does anyone know how "Sticking Up" is done in the big
factories where production is automated. Or do they employ Lutefish to do it
? ? ?
>Thank you everyone who has contributed to this thread.
>Best regards,
>Ivor Lewis.
>Redhill,
>South Australia.
Jim Murphy on wed 18 oct 06
Hi Ivor,
Acetic acid [vinegar] changes the pH, which changes bond-energy strengths.
The latest research suggests clay particle "edges" are perhaps more
sensitive [than clay particle surfaces] to pH changes - which changes the
edge "charge" quite readily.
Changing clay particle "edge" charge-strength moves the Stern Layer
"boundary" [which separates the structured-water "adsorbed layer" from
unstructured-water] thereby affecting the "rigid water structure"
composition ... and resultant "binding" or adhesive-like strength.
Or so goes the published "Plasticity" Theories, i.e., thermal-bond-energy
based "Thermodynamic Theory" [Lawrence & West] or electrical-charge based
"Diffuse-Double-Layer Theory" [Geuy-Freundlich].
Best wishes,
Jim
On Wed, Oct 18, 2006, 2:54 AM, Ivor wrote:
> ... suggesting that adhesives work chemically. But
> that implies some sort of chemical reaction and I do not think Acetic acid
> reacts with Glucose syrup or that either react with Clay. So I am wondering
> what the processes are when Spouse is being used.
Marek & Pauline Drzazga-Donaldson on wed 18 oct 06
=20
When I used to drink (good English Beer) - I haven't had a drop for over =
18 years now (Alchoholic in remision) - I could spit weld any clay slabs =
whetrher they were bone dry or leather hard. I miss that ability to =
magically bond clay, but I know I prefer myself the way I am now.
Happy potting Marek
Hand made Architectural Ceramics from No9 Studio UK www.no9uk.com
Fully Residential Pottery Courses and more at Mole Cottage =
www.moleys.com
"Tips and Time Travel from a Vernacular Potter" reviews on =
www.keramix.com
an irreverent point of view after 35 years in the game Marek =
Drzazga-Donaldson =20
Assemble a dragon finial at www.dragonfinials.co.uk
Free Works and Mole Cottage DVD's and Video content on all the sites
Ivor and Olive Lewis on thu 19 oct 06
Dear Richard,
Good to get your message by direct mail.
Yes, I understand that comparison. Which would be better, a mixture of
Ti-dioxide and Iron oxide or a mineral that is a blend of the two. In
the end it is determined by the results and the way your own taste
accepts or rejects the effects you observe.
What you say then confirms a remark I made about the nature of the
substance used as the filler or adhesive or call it what you will when
parts are luted, stuck up or joined. You are exercising a
considerable degree of quality control over what you are doing to
prepare a slip with very definite and observable characteristics. Then
you apply this material in a consistent way at a specific time which
determines the nature or physical consistency of the parts being
joined. I hope those who have been reading this thread follow your
example.
I think many of us work within that middle ground you describe, the
place called "Technology" where empirical practice rather than the
theoretical concepts is used to direct our craftsmanship.
To some degree, what is called "Science" is an afterthought. Most
scientific theories are out of date, obsolete in a couple of
generations.
Honestly Richard, if I am working and our climate is unkind with the
relative humidity where my stocking tops are and the clay has gone to
the hard side of leather, then I will score both side of the joint and
slip both parts. But if I am on song then I trust my pre-prepared
deflocculated, screened, water deficient, thickened slip.
Now about these Floc Structures I was photographing this
morning..........
Enjoy your weekend and thanks for the accolades.
Sincere regards,
Ivor
----- Original Message -----
From: "Richard Aerni"
To: ; "Ivor Lewis"
Sent: Wednesday, 18 October 2006 10:35
Subject: Re: Ivor/chemical and mechanical bonding
> Ivor,
> Sorry that I haven't had the opportunity to respond to your reply to
my
> posting defending scoring and slipping for sectional pieces. I
guess my
> excuse would be spending marathon hours in the studio and simply
being too
> tired when arriving home at the computer to deal with it. But you
deserve a
> good reply.
>
> Let me first say that I wouldn't choose to argue science with you,
as you
> appear to be so thoroughly grounded and I'm more of a
seat-of-the-pants
> science guy...just enough knowledge to be dangerous! And you are
probably
> right when you describe the bonding process. But this is kind of
like
> arguing the difference between using a titania-red iron blend in
glazes in
> place of rutile with Ron Roy or John Hesselberth...theoretically it
should
> work perfectly well, but in actual practice (in my studio) there are
> significant differences. I tend to go with what works in my work,
and that
> is derived from a basic theoretical knowledge, tempered by practical
> experience.
>
> In my studio I join pieces in various ways. Some are stacked
immediately
> upon being thrown, and for these I take the fewest
precautions...mostly I
> just angle the joints so that the bottom one is banked like the
curve on a
> racetrack, so that I can counter centrifugal force in a small way.
For
> larger pieces, with more at stake, I also use the serrated rib,
which as you
> point out, gives about 50% more surface with which the other piece
can
> interact. When the pieces have sat for more than a few minutes
before
> joining, I also slip them after scoring, using a slip made from the
clay
> body which has been decanted multiple times so that it's consistency
is just
> slightly creamier than toothpaste from the tube. I have played
around with
> both deflocculated and flocculated slips in this regard, but tend to
go with
> what is simplest and gives the best results. I do floc and defloc
slips for
> use over the pieces later on. And, I tend to pay a lot of attention
to
> their consistency and mesh size. For joining leatherhard pieces, I
> carefully score and slip both sides of the joint and try for a
perfect fit.
>
> It's interesting to note how we must go about our work. I sense
that you
> work from a sound basis in scientific knowledge and then proceed in
a way
> that makes what should happen, happen in your studio. I tend to go
about
> things in the way I have either been taught or noodled through on my
own,
> until there is a problem, when I try to work through to a practical
> solution, using a half-baked imitation of the scientific method
(analysis
> followed by testing, eliminating one variable in each test while
keeping the
> others as constant as possible). When I find something that works,
I try to
> figure out why it worked, but the why is much less important than
the fact
> that it works. It's not that I'm not interested in the truth, it's
more
> that I rely upon my production and sales in order to eat and pay the
rent,
> and have to go with what works best in that equation. Which doesn't
mean
> that I don't pay attention to science, but I'm not a scientist. I
inhabit a
> land somewhere between the realms of pure art and pure science, and
I am
> comfortable there.
>
> I love reading your posts because they almost always teach me
something, if
> not sceince, then a scientific response to a problem, and if not
that, then
> simply your wonderful sense of restraint in replying to a post. I
don't
> think we have any argument in this matter, and I was simply
responding to
> your posting about the importance of chemical bonding and the
misplaced need
> to score, with my own practical experience.
>
> So, I am not defending my position with science, but with an excuse
of
> practical expediency.
>
> Happy potting to you!
> Best,
> Richard Aerni
> Rochester, NY
>
> On Wed, 18 Oct 2006 17:24:50 +0930, Ivor and Olive Lewis
> wrote:
>
> >Dear Mel,
> >I think you are tuning in to my wavelength. Electrons provide that
bonding
> force. But water gives a double dose of bond because the Hydrogen
atoms
> provide the opposite polarity. You should buy yourself a copy of
General
> Chemistry by Linus Pauling. Less that $20 US for first year
undergrad
> chemistry. Low priced knowledge ! ! Section 12-4, p 428 covers the
Hydrogen
> Bond and some of the mysteries of Ice and Water
> >One thing that I forgot to say in my post of yesterday is that if
you are
> scoring shallow grooves which have entry angles of about 45 deg you
increase
> the area of the joint by fifty percent, that means one and a half
times the
> area is contributing to the adhering area.
> >I think there may analogies to the general principles of metal
welding and
> you Mel have that knowledge because you have done the college
courses. Using
> good slip is like soldering. NO filler, just a thin film that blends
with
> both surfaces. With metals an intermetallic alloy forms (Chemistry
for Phil
> in El Ve) that is compatible to both metals. But with clay the
composition
> is constant across the boundary. I am sure that the wetter the slip
with
> high water to solids ratio, the weaker the junction, the greater the
> shrinkage, even if it is less than a millimetre, and the greater the
chance
> of drying cracks.
> >I am not sure about Spooze, never used it. Does the Corn syrup
crystallise
> in the joints ? or is it acitng like a film of solder that alloys to
both
> surfaces?
> >Phil may have something in suggesting that adhesives work
chemically. But
> that implies some sort of chemical reaction and I do not think
Acetic acid
> reacts with Glucose syrup or that either react with Clay. So I am
wondering
> what the processes are when Spouse is being used.
> >Thinking about what William Schran is saying, quality control of
the slip
> may be essential and selected to conform to the nature of the clay
being joined.
> >The suggestion of Randy Moody can be tested if a slip is used that
has a
> differing colour to the base clay, or it could be could be stained.
> Examination of cut sections with a high power lens might reveal
fissures as
> small as ten microns wide given sufficient optical contrast.
> >One final thing, does anyone know how "Sticking Up" is done in the
big
> factories where production is automated. Or do they employ Lutefish
to do it
> ? ? ?
> >Thank you everyone who has contributed to this thread.
> >Best regards,
> >Ivor Lewis.
> >Redhill,
> >South Australia.
| |
|
