|
Do you have a stamp to impress your mark or signature or to even put decoration on each new piece of pottery or ceramic that you make?
A personal ID will stay with the pottery or ceramic forever?
It is easy to make a stamp that looks professional.
Once you have a little experience, you’ll find other functional and decorative uses for stamps.
Perhaps the simplest mark to start with is a two letter clay signature stamp with your initials.
Making A Signature Stamp
from an article by Roger Graham, near Gerringong, Australia.
to find more on this subject check out Rogers pages here.
Signature stamps start by making a small plaster slab on which to engrave your design.
Use 2 3/4 ounces of plaster and 1 3/4 ounces of water.
Stir gently until smooth, wait until the mixture is thick and creamy.
Pour it onto a smooth, soaped surface, such as a piece of glass and let it form a pancake.
When the plaster sets, it should lift off easily.
There’s no need to wait for the plaster to become completely dry.
It engraves more easily when damp.
Engrave your pattern into the flat surface with a pointed tool.
Aim for deep narrow grooves rather than broad shallow ones.
Letters don’t need to be reversed for initial stamps.
While engraving, occasionally press a bit of soft clay into the pattern to check the progress.
Look critically at the result and make adjustments as you go for example, add serifs on letters or extra depth in loops.
When satisfied with the pattern, draw four pencil lines around it like a “#.”
This is where the clay will be cut away when trimming the stamp to size.
Take a small piece of clay, about as big as a marble, and press it very firmly into the engraving.
Push down with something firm and solid so you can get the sharpest, crispest, most detailed print possible.
Leaving the little piece of hard pressed clay undisturbed on the plaster, lightly score the back and add a dab of slurry.
Make a little handle from the same soft clay.
Score the end, apply a dab of slurry and join it firmly to the scored side of the stamp with a twisting motion.
Try not to disturb the stamp itself, which is still attached to the plaster.
Don’t worry about the shape at this stage.
It’s better to trim it later.
For the next step, refer to the # pattern you drew earlier.
The lines should extend beyond the edges of the hard pressed clay.
Carefully cut along each line with a sharp narrow blade and remove the unwanted clay.
Lift the entire clay stamp away from the plaster.
If it looks good, make some extras.
When the clay is leather hard, make an smooth and trim the edges.
Stamps work best if fired to bisque temperature.
Fired stoneware stamps are harder, but they aren’t porous so the clay tends to stick to it.
That wasn't so bad now, was it?
You have a tool to mark all your pottery and ceramics.
Making A Functional Stamp
This next stamp is useful for making a neat finish when adding a handle to your pottery or ceramics.
Carve the pattern directly into leather hard clay and bisque fire it.
Any simple geometric design will do, but of course you’ll have to think in reverse when doing the carving.
This stamp’s purpose is only partly decorative.
Impressing the stamp firmly over the end of a newly added handle helps ensure that the handle and the mug body are well joined.
You must push this kind of stamp a bit more harder.
Push hard so the clay beneath the handle gets a good firm squeeze.
Wiggle the stamp with a twisting motion to make the clay rise up into the deeper cavities of the stamp.
That way you’ll get both a secure joint and a crisply defined image.
Detail of a finished pottery mug with Temmoku glaze.
A simple imprinted stamp such as your initials wouldn’t be very successful under a dark glaze, since the grooves of the design would simply fill up with glaze and disappear.
If you’re using a dark opaque glaze, it’s better to create a pottery stamp designed to rise above the surface, so it stands out when the glaze breaks away from the upstanding ridges.
Recipes
Talc White Glaze.
Cone 9 to10
Oxidation or Reduction
Calcite, Calcium Carbonate)..................13%
Talc ................................16%
Potash feldspar ............ 27%
Ball clay ........................ 16%
Silica (flint) ....................28%
TOTAL...............................100%
This is a good reliable glaze for the interior of domestic stoneware, smooth white, not too glossy, okay over cobalt blue slip, if not applied too thickly.
For a pale pastel blue.
ADD
0.25% cobalt carbonate (very pale),
0.5% a bit stronger
1% stronger still
Good as a misty over spray on the baby plate.
Copper Green Glaze.
Cone 9 to10
Oxidation
Calcite, Calcium Carbonate).................. 9%
Dolomite........................ 9%
Zinc oxide .................... 5%
Potash Feldspar..............45%
Kaolin ............................ 9%
Silica (flint) ....................23%
TOTAL................................100%
ADD
Copper carbonate ..........5%
Best with a fairly thick coat.
For rich, even green, the kiln atmosphere must be oxidizing all the way.
Good over sgraffito decoration or imprinted stamps.
Clear
Cone 10
Calcite, Calcium Carbonate)..................19%
Talc ................................ 7
Potash feldspar ..............15
Ball clay ........................29
Silica (flint) ....................31
TOTAL..................................101%
General purpose clear glossy glaze, okay over colored slip in a stamped imprint.
Decorative Stamps
Once you discover how to design stamps effectively, creative ideas for other decorative stamps will pop up as well.
Geometric designs?
Flower shapes?
Animals?
This next stamp made according to the info above with a bunny design is used to decorate a baby’s plate.
The traditional baby’s plate has fairly vertical walls with a thick, strong horizontal rim. The idea is to decorate the rim with stamps, fill each imprint with cobalt blue slip
and finish with a clear glaze.
Engraved four different bunny shapes on a small plaster slab.
Following the previous steps, make several stamps for each bunny design.
Although the stamps could be left flat, it’s best to trim away the surplus around the edges with a thin sharp knife after the clay dries a bit.
Using stamps decoratively takes a little more planning than signature stamps.
If you’re planning to apply stamps to rims, you must make the rims wide and thick enough to accept whatever stamp you have in mind.
You might fancy a whole bunch of bunnies in the center of the plate, it’s easy to get carried away.
You aren’t limited to just stamping the design.
Draw a few blades of grass with a pointed tool.
Remember that you intend to fill the design with colored slip, so make the impressions deep.
When considering the slip you’ll use, make sure it is thin enough to brush on smoothly, but thick enough to fill the imprinted pattern when it dries.
It’s simple to make slip from the same clay as the pottery, just mix the slurry from the wheel tray to a thin creamy consistency.
Cobalt blue, a traditional color for a baby’s plate, is easily achieved by the addition
of cobalt oxide to the slip.
A good proportion is 1.5 grams of oxide for every 3 1/2 ounces of dry clay.
Thin, creamy slip contains about 50% solids by weight, so you’d use 1.5 grams of oxide for every 6 3/4 ounces of slip.
Close approximation is good enough; it’s not rocket science.
If you don’t have scales suitable for measuring tiny amounts, 1.5 grams of black cobalt oxide is about 1⁄4 of a level teaspoon.
Mix the measured amount of oxide thoroughly into the slip and mix well to ensure a uniform mid gray color.
If you choose to use cobalt carbonate instead of oxide, you’ll probably need to double the amount.
Carbonate yields the same blue color in the end, but the slip will be pale pink instead of gray and harder to see when applying.
The plate is ready for the slip when leather hard.
Use a small soft bristled brush to dab the slip into every small imprint without damaging the pattern.
When the slip dries a bit, you may decide to revisit parts and add more slip to fill up the print.
But you’ll find the cobalt blue color is strong enough to come through clearly even if very thin.
By the time you’ve dabbed slip into every imprint, the project may look a bit messy. Don’t throw a fit!
It will come up smiling when you clean it up, but you have to be patient.
Leave the pottery until it’s completely dry before you attempt to rub the surface down. Don’t rush this stage.
This plate was thrown on a small bat and has not yet been cut off.
To avoid making unsightly bumps on the underside, delay cutting off until all imprints are in place.
Don’t scrape the excess slip away with a knife.
It takes forever and does an inferior job.
Steel wool or one of those woven plastic pot scouring pads works well.
Rub carefully and don’t inhale the dust.
Do this in a well ventilated room with a strong exhaust fan.
If you don’t have access to something similar, do the job outside and wear a mask.
If you find you’ve missed a detail, add another dab of slip, wait a little longer and rub again.
After the pottery is bisque fired, the dull gray slip should become cobalt blue.
If you missed any little specks of slip when rubbing at the greenware
stage, they’ll be easier to see now.
Just rub a bit more, using sandpaper this time.
You won't find little gaps in the imprints after the bisque firing, but if you do, it’s possible to make minor alterations even at this late stage.
With a sharp tool, scrape out a groove and dab in a little more slip.
For a small repair, it’s fine to raw glaze over the top.
The Cone 10 Clear is a glossy glaze that works well for this.
It is unlikely to obscure the pattern, even if applied thick.
The Talc White Glaze is more interesting, but if applied too thick, the bunnies end
up hidden in a fog.
If you can spray glazes, you can apply a thin misty spray of pale blue
over the main glaze.
| You can preach a better sermon with your life than with your lips. |
|
