[Clayart] Underglaze for Screenprinting on Clay

[Sharon Wetherby]

Do any of you have experience screenprinting on clay? I need advice.

I'm playing around with screen printing images onto clay with black
underglaze. Problem: I cannot get the underglaze thick enough. Tried a
"Magic Formula" (Karo Syrup, Mason stain, Duncan EZ Stroke, and CMC) from an
old article in Pottery Making Illustrated. According to the article: if
the mix is too thin, add more Karo syrup; if too thick, add more CMC. Have
added more Karo; still too thin. I found one bit of advice in the ClayArt
archives to add Epsom salts to thicken the underglaze. Hasn't helped;
should I add a bunch of Epson salts? Have had a small container of
underglaze sitting open for over a week. It's still too thin. I've been
wondering if I can add an acrylic medium to thicken it up. Any thoughts on
this?

Enjoy the week,
Sharon Wetherby
Fort Worth, TX, USA

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[Paul Lewing]

On Nov 4, 2013, at 7:01 AM, Sharon Wetherby wrote:
I'm playing around with screen printing images onto clay with black
underglaze. Problem: I cannot get the underglaze thick enough.
Tried a
"Magic Formula" (Karo Syrup, Mason stain, Duncan EZ Stroke, and CMC)
from an
old article in Pottery Making Illustrated. According to the article:
if
the mix is too thin, add more Karo syrup; if too thick, add more CMC.
Have
added more Karo; still too thin. I found one bit of advice in the
ClayArt
archives to add Epsom salts to thicken the underglaze. Hasn't helped;
should I add a bunch of Epson salts? Have had a small container of
underglaze sitting open for over a week. It's still too thin. I've
been
wondering if I can add an acrylic medium to thicken it up. Any
thoughts on
this?

I've never screened onto clay but I've done a LOT of screening using
china paint on fired glaze on tile, and I've tried virtually
everything you can think of as a medium, including corn syrup, acrylic
medium, and CMC gum. You're right, corn syrup is not the best
choice. Too gummy, and the powder separates from the medium.
I assume you're using powder, not liquid underglaze. The most
critical thing about a screening medium is the consistency, which
should be about like mayonnaise. If you start with liquid underglaze,
you'll inevitably end up with a mixture that's too thin, which will
bleed out under the screen, blurring the detail. You need to start
with powder so you can put a quantity of the liquid medium in a jar or
cup and mix in powder till it's the right consistency. You'll know
pretty quickly how think you need it to be.
Next you need to ask yourself whether you need the image to dry or
not. If you're doing more than one color without firing in between
coats, you need what china painters call a closed (means it dries)
medium. If you don't care if it ever dries, you can use either a
closed or an open medium. If I'm only firing one color, my favorite
medium is plain old antifreeze. It virtually never dries. If I'm
going to print two colors without firing first, I use a mixture of
antifreeze and gum arabic, maybe 1 part gum to 2 parts antifreeze.
This will dry hard enough that I can lay the second screen down on the
first image without blurring it. At least on glazed tile, you can't
print one color over another, or it will pick up the first image
rather than lay down the second. But you can print one color next to
another. You could probably use CMC instead of the gum arabic, but my
experience with using gum arabic is that pure gum won't work, because
the color will crawl in the firing. Might not happen on clay and
might not happen with CMC. And a tip: even though all these mediums
are water-based, if you find that the mixture is too thick, don't add
water to thin it, just more medium. Water will separate from the
medium leaving you with blurry details again.

By the way, the problem with acrylic medium is that it dries too
hard. If it dries in your jar you can't get it reconstituted, and if
it dries in your screen it will block your screen, ruining it.
Another thing. If you find your powdered material won't go through
the screen, you need either to ball mill it or switch to a coarser
screen.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com

[Robert Harris]

I've only done it a few times, monocolour. I made up a very thick paste of
"glaze" then added liquid starch and water until it was the right
consistency.

--
----------------------------------------------------

[Fredrick Paget]

10 or 15 years ago I was playing around with this and found a website
in Australia that was selling the "Print GOCCO" system from Japan.
They are still there and they sell screen printing ink for ceramics.
I still have a set of them. I bought their big Gocco kit so I am a
life member, I guess. Anyway that is what it says on the kit. I just
looked.

See <http://www.nehocdirect.com/launch.html> They take Paypal and
have everything you could need.

Riso in Japan quit making their Print Gocco stuff but Nehoc has continued.

Regarding the concoction you have you could thicken it up by adding
corn starch or arrowroot and heating on the stove. Basic sauce
cooking.

You need some frit in that recipe and I suppose the Duncan easy
stroke provides that. Mason stains don't melt so the frit does that.

I hope this helps,

Fred Paget
Twin Dragon Studio
Mill Valley, CA, USA

>Do any of you have experience screenprinting on clay? I need advice.
>
>I'm playing around with screen printing images onto clay with black
>underglaze. Problem: I cannot get the underglaze thick enough. Tried a
>"Magic Formula" (Karo Syrup, Mason stain, Duncan EZ Stroke, and CMC) from an
>old article in Pottery Making Illustrated. According to the article: if
>the mix is too thin, add more Karo syrup; if too thick, add more CMC. Have
>added more Karo; still too thin. I found one bit of advice in the ClayArt
>archives to add Epsom salts to thicken the underglaze. Hasn't helped;
>should I add a bunch of Epson salts? Have had a small container of
>underglaze sitting open for over a week. It's still too thin. I've been
>wondering if I can add an acrylic medium to thicken it up. Any thoughts on
>this?
>
>Enjoy the week,
>Sharon Wetherby
>Fort Worth, TX, USA

--

[Suzanne Wolfe]

I have found that an underglaze like EZ stroke works very well. However,
you have to leave it uncovered for a while until it becomes thick like
mayonnaise (or even a bit thicker) and then I add a bit of glycerin to it
so that it does not dry so fast in the screen. This seems to work very
well for me. I will add, however, that I do not screen directly onto clay,
but first onto newsprint, and then use slip (sometimes just water, if I am
lucky) to transfer to wet to leather-hard clay.
Suzanne Wolfe

[S Cary, Potter]

Microwave it till thick enough. Speeds up the evaporation. Use a somewhat shallow container helps too.

S Cary, potter
Make something beautiful every day.

[Fredrick Paget]

Antifreeze is usually mostly ethylene glycol and is poisonous.
Sometimes they make a safer antifreeze usingp propylene glycol,
Propylene glycol is nonpoisonous and is commonly fed to cows for some
trouble cows sometimes have. It is also an additive in foods.

Anyway you can get it from any vet supply house and it is cheap. I
used it in my inkjet sticky ink embossing .

Fred Paget
Twin Dragon Studio
Mill Valley, CA, USA

>On 4/16 Paul Lewing wrote:
>Next you need to ask yourself whether you need the image to dry or
>not. If you're doing more than one color without firing in between
>coats, you need what china painters call a closed (means it dries)
>medium. If you don't care if it ever dries, you can use either a
>closed or an open medium. If I'm only firing one color, my favorite
>medium is plain old antifreeze. It virtually never dries. If I'm
>going to print two colors without firing first, I use a mixture of
>antifreeze and gum arabic, maybe 1 part gum to 2 parts antifreeze.
>This will dry hard enough that I can lay the second screen down on

>the first image without blurring it. .
>Paul Lewing


--

[Paul Lewing]

On Nov 4, 2013, at 4:49 PM, Fredrick Paget wrote:

Antifreeze is usually mostly ethylene glycol and is poisonous.
Sometimes they make a safer antifreeze usingp propylene glycol,
Propylene glycol is nonpoisonous and is commonly fed to cows for some
trouble cows sometimes have. It is also an additive in foods.

Regular antifreeze is only poisonous if you drink it. Don't drink it.
I've tried propylene glycol for this and it works, so does glycerine.
I use antifreeze because of all the double alcohols, of which there
are several more than these three, it's the thinnest. That means you
can get more powdered color into it before it gets too thick.
And the fumes won't be any different than burning off gums or any
other of the double alcohols.

Paul Lewing
www.paullewingtile.com
www.paullewingart.com

[Terrance (Terry) Lazaroff]

Paul;
I think the point here is that if you have a pet, use the non toxic antifreeze. Dogs go crazy for antifreeze and they will lick up any drops quickly, and they get sick.

Terrance

Antifreeze is usually mostly ethylene glycol and is poisonous.
Sometimes they make a safer antifreeze usingp propylene glycol,
Propylene glycol is nonpoisonous and is commonly fed to cows for some
trouble cows sometimes have. It is also an additive in foods.

Regular antifreeze is only poisonous if you drink it. Don't drink it.
I've tried propylene glycol for this and it works, so does glycerine.
I use antifreeze because of all the double alcohols, of which there
are several more than these three, it's the thinnest. That means you
can get more powdered color into it before it gets too thick.
And the fumes won't be any different than burning off gums or any
other of the double alcohols.

[Paul Lewing]

On Nov 5, 2013, at 6:34 AM, Terrance (Terry) Lazaroff wrote:

I think the point here is that if you have a pet, use the non toxic
antifreeze. Dogs go crazy for antifreeze and they will lick up any
drops quickly, and they get sick.

Exactly. And actually there's probably more danger for cats. You
don't normally have the antifreeze on the floor. Unless you're a lube
shop you notice when some of it goes on the floor. But cats can get
up on your tables.
But there's really no danger to you in having antifreeze around your
studio.
Paul Lewing
www.paullewingtile.com
www.paullewingart.com

[Dorothy Parshall]

They die if allowed to ingest it. Dorothy

On Nov 5, 2013, at 9:34 AM, Terrance (Terry) Lazaroff wrote:

> I think the point here is that if you have a pet, use the non toxic
> antifreeze. Dogs go crazy for antifreeze and they will lick up any
> drops quickly, and they get sick.