sandblasting

updated tue 1 may 12

Roger Bourland on sat 5 jul 97

Periodically I see references to sandblasting as a texturing method in
clay. I would like to delve into this, but can't seem to find any
resources, written or alive (!) that have knowledge and experience with it.

Can anyone suggest something or someone that would help me learn the
fundamentals of how to do it, what tools and materials are required and who
are some of the potters who have done it well?

Best,

Roger Bourland

Harvey Sadow on sun 6 jul 97

I guess it's me that you are looking for Roger. When I began developing
dry surface color and texture options for raku in the late 1960's I
fooled around with revising fired surfaces in a variety of ways but it
wasn't until the mid seventies, when I saw a brick wall in downtown
Whitewater, Wisconsin being sandblasted that I really saw the "door
open". While walking down the street, I saw the place where the
sandblasting crew had stopped for lunch. The patina of age on the old
red brick gave way to the bright tomato red of the sandblasted brick. I
took a mental picture of that very graphic image, and walked on,
thinking, "man, I would love to do that to fired clay", and then the
light bulb went on....BRICK IS FIRED CLAY! I went across the street and
waited for the workers to come back, watched them for about half an hour
and then started asking questions. They suggested going to Sears,
getting a sandblasting kit and a compressor with at least a 20 gallon
tank and "just do it" (they were channeling future Nike commercials).
One of them also suggested that I check with the guys at the local body
shop, where sandblasting is also done, which I did, and got the story on
several different kinds of abraisives, goggles, compressors, etc. Then
I went to Sears and spent some money, and have been experimenting away
ever since. You can still buy a basic sandblasting kit at Sears. It is
nothing more than a blasting gun, hose and a container for the sand
which allows it to feed into the gun.

I use sandblasting to create texture, remove gloss, remove and/or expose
color layers from multiple fired pieces and occasionally to remove
surfaces right down to the clay in places, so that I can start over,
building up surfaces on isolated areas of a piece. Therefore the
sandblaster functions as a drawing tool, an eraser, and a modeling
tool.
I am actually discussing a few workshops at the moment which will
include sandblasting demonstrations, and maybe some hands on, or gloves
on, too. I will have the workshop hosts post notice of them when dates
and times are finalized.

Meanwhile, here are some of the the variables. Some of the abraisive
material you use are very gentle on fired surfaces, while silicon
carbide, for instance, will rip fired glaze up easily. There is coarse
sand and fine sand. There are spray guns and "air erasers", which are
tiny sandblasters which are like airbrushes for doing detail work on
paper. They aslo work on clay). Pressure is a variable, as is the
distance from the object. Of course, all this depends on how hard the
fired surface is. Some glazes are very soft, while others are quite
hard. Try lots of things, and wear goggles and gloves. You can spray
cheap abraisives out in the yard, or build a spray booth for blasting.
Old refrigerators make really good sandblasting booths. Put a piece of
glass into the door with aquarium sealer and cut holes in the door for
gloved hands. The light bulb inside comes in handy, too.

Harvey Sadow

Timothy Dean Malm on tue 8 jul 97

I first used sandblasting as a method of "aging" ceramic relics in 1979.
Dry clay and an available blasting box were the primary needs. Particle
size (abrasive), pressure, and proximity to the surface of the clay
provided the amount of "erosion" needed. I used the method again in the
'80s to etch through multiple layers of mason colored slips. Various
masks/stencil materials can be used, determined by trial and error. It
does create significant dust.

Tim Malm
Seattle

Arturo DeVitalis on wed 9 jul 97

To see what happens to your pots if sandblasted ask your local tombstone
maker if they would test blast some pieces in exchange for some of your
lovely work.

Leslie Ihde on thu 14 may 98

THis list has helped me out many times- perhaps people will be equally
generous with one more question.
I'm interested in sandblasting and I wondered what the most economical
system people would recommend might be.Would it be possible to do with a
Critter? Or an auto body sandblaster- (I priced one at 45)
THanks for any thoughts.
I know clean sand must be used.
Leslie
Vestal NY

Vince Pitelka on fri 15 may 98

>I'm interested in sandblasting and I wondered what the most economical
>system people would recommend might be.Would it be possible to do with a
>Critter? Or an auto body sandblaster- (I priced one at 45)

Leslie -
Only a device specifically designed for sandblasting will do the job.
Anything will immediately be ruined by the abrasion of the sand. The small
readily available sandblasting guns look slightly similar in design to a
spray-gun, but have much larger internal passages to accommodate the
sand-laden air. A powerful airstream passing a side port creates a vacuum,
drawing sand from the sand reservoir. An incredible amount of abrasion
occurs within the gun assembly, and the parts must be specially designed.
The tip of the gun is replaceable, and is usually a ceramic material, as
this is where the abrasion is most intense.

Small sandblasters are available with an attached one-quart screw-on sand
reservoir just like a spray-gun. A slightly more elaborate version has a
hose connecting the gun to a much larger gravity-feed reservoir. I prefer
the latter, because you have more freedom of movement with the gun, and if
you are doing any quantity of sandblasting you will need to fill the
reservoir far less frequently. A slightly more expensive model has a
pressurized sand reservoir, which makes the sand feed more consistent.

Good industrial sandblasting set-ups have an enclosed cabinet with a window,
a dust filter, and heavy attached gloves for reaching in and manipulating
the work and the sandblasting gun. All the sand is gathered in the bottom
of the cabinet and recycled through the gun. When using the less expensive
sandblasters you must work outside, and it helps to do the sandblasting on a
large tarp, so that you can reclaim and reuse most fo the sand. It makes a
big mess - it is amazing how far those grains of sand fly through the air
when they rebound off the work being sandblasted. If you drape the tarp
properly you can catch most of the sand and minimize the mess.

When sandblasting the sand will rebound off the work with great force, and
you must protect yourself and your clothing. Wear a hat and a full face
shield, or preferably a sandblasting helmet, which covers your entire head
and has a window in the front. And of course, wear a good quality dust mask
designed for ultra-fine silica particulates. It is also a good idea to wear
a plastic poncho to minimize dust in your clothing.
Good luck -
- Vince

Vince Pitelka - vpitelka@DeKalb.net
Home 615/597-5376, work 615/597-6801, fax 615/597-6803
Appalachian Center for Crafts
Tennessee Technological University
1560 Craft Center Drive, Smithville TN 37166

JJHerb on sat 16 may 98

system people would recommend might be. Would it be possible to do with a
Critter? Or an auto body sandblaster- (I priced one at 45)
Thanks for any thoughts. I know clean sand must be used.
Leslie
Vestal NY>

Let s go over this hardness thing one more time. Things that are hard scratch
and abrade things that are soft. There is a scale of hardness that allows us
to estimate the effects of rubbing one object on another. The higher the
number in this Mohs mineral hardness scale, the harder the material. Diamond
(scale number 10) scratches everything. Talc (Scale number 1) scratches
nothing. Most metals are around 5.5 and quartz, the main component of sand,
is 7. This means that running sand through your Critter will enlarge all the
holes that it runs through until all the metal in some area is worn away.
This will probably void the warranty. If you examine the auto body
sandblaster, you will note that the entire sand travel path is either rubber
and replaceable or a very hard material like a high alumina ceramic or
tungsten metal and also replaceable. Go with the machine designed for the
task. Wear breathing and eye protection!!

A point of interest, most ceramic material is harder than quartz so the
sandblasting effect is not so much a scratch abrasion as an impact fracture
process. The impact of the sand grains shatters some of the body of the pot
and the air current carries the resulting particles away. Some sandblasting
operation, like for gravestones, use aluminum oxide grit - hardness scale
number 9 - to get a more effective result. It is much easier, and gets a very
different effect, to sandblast greenware. In this case, limestone grit -
hardness scale 3 - would be sufficient to remove all manner of clay from a
green pot. Breathing and eye protection, again!!

Joseph Herbert
JJHerb@aol.com

LOWELL BAKER on mon 18 may 98

I published an article on sandblasting in CM in the early 80s, and I
have responded to this list in the last yearon the subject. You can
probably find
something in the archives. You can buy the sandblaster for about
$12.00. The big caution is silica dust and flying sand. Resist with
paper, masking tape, inner tube rubber, etc. duct tape is a mess.
W. Lowell Baker
The Unioversity of Alabama

John Tilton on sun 2 aug 98

When the shelves come home after sandblasting I always wash them with a
hose and brush. Just squirt tham really hard and set them in the sun to
dry. I've never had the problem that Pete describes. I like to apply the
kiln wash while they are still damp--not soaking wet but just a little
damp.

Be sure to let them dry completely before firing.

A couple years ago I got Advancer shelves---I doubt they will ever need
to be sandblasted as the glaze just seems to come right off.


John

--
John Tilton
16211 NW 88th Terrace
Alachua, Fl. 32615
904-462-3762
Web site: http://www.tiltonpottery.com

Michele Jurist on wed 19 may 99

Hi everyone:

I was wondering if anyone has any experience with sandblasting bisqued ware
to create a pitted look. What kind of sandblaster is suitable (not too
powerful)? Any tips for using it? Also, preferably, if there is a chemical
that would cause a pitted look without sandblasting, does anyone know what it
would be? Would muriatic acid work?

Thanks in advance to everyone who replies.

Michele

Joanne Van Bezooyen on thu 20 may 99

I've used old ground coffee grounds wedged into clay and when it burns out the
surface is pitted.....try it.

Michele Jurist wrote:

> ----------------------------Original message----------------------------
> Hi everyone:
>
> I was wondering if anyone has any experience with sandblasting bisqued ware
> to create a pitted look. What kind of sandblaster is suitable (not too
> powerful)? Any tips for using it? Also, preferably, if there is a chemical
> that would cause a pitted look without sandblasting, does anyone know what it
> would be? Would muriatic acid work?
>
> Thanks in advance to everyone who replies.
>
> Michele

James Blossom on thu 20 may 99

Michele,

You might try working with unbisqued bone dry clay instead. A sponge
will
give you that pitted look without all the dust and bother of sandblasting.
A bonus is that by applying Thom(p)son's (sp?) Weather Seal and letting
it dry you can leave raised patterns that are not pitted where the sealant
was applied. The sealant can even be silk-screened on, for those non-
neo-Luddites amongst us....

"All truths are half-truths. It is trying to treat them as whole truths
that plays the devil." ---- Alfred North Whitehead

J. Blossom
Sleeping Dog Designs

In the perfumed spring of New Mexico




-----Original Message-----
From: Michele Jurist
To: CLAYART@LSV.UKY.EDU
Date: Wednesday, May 19, 1999 2:14 PM
Subject: Sandblasting


>----------------------------Original message----------------------------
>Hi everyone:
>
>I was wondering if anyone has any experience with sandblasting bisqued ware
>to create a pitted look. What kind of sandblaster is suitable (not too
>powerful)? Any tips for using it? Also, preferably, if there is a
chemical
>that would cause a pitted look without sandblasting, does anyone know what
it
>would be? Would muriatic acid work?
>
>Thanks in advance to everyone who replies.
>
>Michele

CNW on thu 20 may 99

I recently sandblasted a sculptural piece that I had accidentally glazed
with a glossy black on a ^04 earthenware. I don't know about getting a lot
of texture, it sort of relative. But then I just took it down to the local
monument place and didn't do the sandblasting myself.

What I assume about sandblasting is that it normally is used to remove a
layer(s) and smooth a surface.

You can mask areas and remove the clay in all the unmasked areas.

It did do some kind of neat things with the glossy glaze--sort of a misty
surface with shiney parts underneath and in between the places that the sand
hit. Most of it I had him take down to the clay surface. They were kind of
funky about trying to sandblast it so if you are not doing the sand blasting
yourself you may need to do some tap dancing to convince them that the
bisque will not fall apart.

Somebody else might have more information about changing grit size.

Celia in NC-- glad of the rain but wish it had lasted a few more hours.
I just had my husband talked into going to the new Northern Equipment and
the Tractor Supply to look for interesting stuff.
But it dried off enough to cut hay. Rats.

NakedClay@aol.com on thu 20 may 99

Hi Michele, and other dedicated pot-pitters!

If a pitted surface is what you seek, put down the sand blaster! Sand
blasting often produces poor results, and may damage the surface of your pot.
Sand blast only when all else fails.
I suggest that you collect coffee grounds from a nearby pot (almost everybody
knows someone who drinks perc coffee), and press the grounds onto the surface
of the pot, next time you[re throwing. Use dried or slightly "wet" grounds
for the best results. Coffee grounds produce a subtle, yet vivid pitted
surface to a pot. For a moreso pronounced pitted surface, you may want to
use rice or sawdust. Once again, dry or slightly moist raw rice or moist saw
dust is best for applying to the wet surface of your pot. I use a slab roller
to "impress" my clay with these substances. A wheel potter will have a bit
more difficulty applying these materials, but it can be done with a paddle or
a gentle hand motion. All of these substances can be left on the clay surface
to "burn out" during the bisque firing.

For a wild time with pitted surfaces, try rust from an old metal object (I
use an old rusty table here in my studio), or flower petals, such as
marigolds, for a pitted surface with a "zing." The rust will melt during the
glaze fire, so apply carefully near the top of your ware. Flower petals,
leaves, and other plant materials will "burn out," during the bisque firing.
On the tiles I make, I've used both flower petal impressions which were
"rusted," making an interesting, unusual coloration in the impressions. Once
bisque fired, I placed crushed bottle glass into the impressions, and
high-fired the tile, for an unusual texture. As always, experiment with
caution. Use extra kiln shelf wash when high-firing melting materials to your
wares, especially when you fire glass or metal pieces into your clay for the
first time.

Best wishes, and happy pitting! (I wrote this for a mere "pittance!").

Milton NakedClay@AOL.COM

Ben Shelton on thu 20 may 99

If you want to tape and blst for patterns, Bisque to 018. If not just blast
on green ware or leather hard.
I got my blaster at Lowes for about $20 ceramic tip and all. Eats a lot of
air. You'll need a good compressor. Ben
-----Original Message-----
From: Michele Jurist
To: CLAYART@LSV.UKY.EDU
Date: Wednesday, May 19, 1999 5:14 PM
Subject: Sandblasting


>----------------------------Original message----------------------------
>Hi everyone:
>
>I was wondering if anyone has any experience with sandblasting bisqued ware
>to create a pitted look. What kind of sandblaster is suitable (not too
>powerful)? Any tips for using it? Also, preferably, if there is a
chemical
>that would cause a pitted look without sandblasting, does anyone know what
it
>would be? Would muriatic acid work?
>
>Thanks in advance to everyone who replies.
>
>Michele
>

Brian Crocker on fri 21 may 99

Un-- diluted Hydrocloric Acid should work but you will have to mask it well.
Hydrofluric Acid will most certainly work, it also etches glass.

>>>>>>>>>>>BUT IT IS ONE OF THE MOST DANGEROUS OF ACIDS<<<<<<<<<<<<

>>>>>>>IT SHOULD ONLY BE HANDLED BY AN EXPERIENCED TECHNICIAN<<<<<<


At 05:13 PM2:10: 19/05/99 EDT, you wrote:
>----------------------------Original message----------------------------
>Hi everyone:
>
>I was wondering if anyone has any experience with sandblasting bisqued ware
>to create a pitted look. What kind of sandblaster is suitable (not too
>powerful)? Any tips for using it? Also, preferably, if there is a chemical
>that would cause a pitted look without sandblasting, does anyone know what it
>would be? Would muriatic acid work?
>
>Thanks in advance to everyone who replies.
>
>Michele
>
>
Brian Crocker.
4 Erica Street,
Tea Tree Gully 5091,
South Australia. [e.mail] crocker@dove.net.au

With them the Seed of Wisdom did I sow,
And with my own hand labour'd it to grow:
And this was all the Harvest that I reap'd --
"I came like Water, and like Wind I go." The Rubaiyat.

Dorothy Weber on sat 22 may 99

My only suggestion is that when you use your sandblaster you use very fine
sand and turn the air pressure down low at first. Just keep turning up the
air pressure until your satisfied. Use the cheap-o type sandblaster kit
purchased at any major hardware like Lowes, Home Quarters etc. Of course, you
need a compressor that will go up to 110lbs at least. Start with 20 lbs. and
work up. Good luck.
John in Manakin-Sabot....Virginina

Gail Dapogny on sat 22 may 99

After fighting a never-ending battle with pits in high-fired glazes, I find
myself reading these posts with morbid fascination! It sort of reminds me
of the cartoon which shows a dog trotting by a "Flea Market" sign,
muttering to himself, "You mean they pay money for those?" ! (Only
kidding: it sounds like a neat technique.)
--Gail



>If a pitted surface is what you seek, put down the sand blaster! Sand
>blasting often produces poor results, and may damage the surface of your pot.
>Sand blast only when all else fails.
>I suggest that you collect coffee grounds from a nearby pot (almost everybody
>knows someone who drinks perc coffee), and press the grounds onto the surface
>of the pot, next time you[re throwing. Use dried or slightly "wet" grounds
>for the best results. Coffee grounds produce a subtle, yet vivid pitted
>surface to a pot. For a moreso pronounced pitted surface, you may want to
>use rice or sawdust.

Gail Dapogny
1154 Olden Road
Ann Arbor, MI 48103-3005
(734) 665-9816
gdapogny@umich.edu

Faye Clarke on sat 22 may 99

One potter I know-- used perilite mixed into the clay when he made the
piece and then sandblasted the holes that were in the piece after bisque
for more depth and texture...



At 05:13 PM 5/19/99 EDT, you wrote:
>----------------------------Original message----------------------------
>Hi everyone:
>
>I was wondering if anyone has any experience with sandblasting bisqued ware
>to create a pitted look. What kind of sandblaster is suitable (not too
>powerful)? Any tips for using it? Also, preferably, if there is a chemical
>that would cause a pitted look without sandblasting, does anyone know what it
>would be? Would muriatic acid work?
>
>Thanks in advance to everyone who replies.
>
>Michele
>
>

Bonnie Staffel on sat 22 may 99

May 21, 1999

Hi Michele and other mudslingers 8>)

I glue pebbles, rice, coffee grounds, wrapped cord or rope, you name it
to a wooden paddle, wooden spoon, or light board. Those who throw pots
can then paddle away, vent frustrations, love the sounds, etc., and get
the pitted look easily without the mess of dealing with loose material.
I even rolled a pot in the gravel of my driveway.

Bing, Bang, Bop away, Bonnie Staffel of Charlevoix, MI where summer is
coming fast!!!

Phyllis E. Tilton on sat 22 may 99

Hi to Pot-Pitters, as Milton calls some of you. I talked with a potter at an
art festival that had a cratered, pitted, rough surface on his pots. He told
me he had mixed silicon carbide into the glaze. I have no clue as to the
percentage, safety, cone, porosity of the ware,etc. Maybe someone has
information regarding this? I hope that I remembered the correct name of the
chemical.

Phyllis Tilton
Daisypet@aol.com

Bobbruch1@AOL.COM on fri 15 nov 02

<<<idea

The sandblasting of Red Shino (cone 10 Reduction) leaves a mottled effect
with a grayish background and areas of a salmon hue over it. There is
charred looking black on some of the edges, the gray and black being similar
to pit firing results. If you sandblast the surface, you can leave the Red
Shino on the rim which creates an interesting contrast with the now matte
surface that results from the sandblasting. This had to be done DELICATELY as
the salmon color will disappear easily. It is also possible to remove the
gray background (which is the remnant of the glaze) leaving very ugly
patches. I would suggest trying this with test pieces, as you can ruin good
pots fairly easily. That is why the glass department's sandblaster is the
way to go with the exception of the fact that these machines are both large
and expensive.

Bob Bruch