Custom Single-Page Underglaze Transfer?

[bny]

The lavender is most likely SC13 Grapei judging from sample bottle emptiness.  I noted my earlier hot oil ink intaglio practice behind soap brushing in transfer (look for videos of Burleigh transfer shop process and Spode museum hot plate printing demonstration), and it is probably unnecessary or even counterproductive here.  Or it might have lent to the softening of line in the left example.

[neilestrick]

I don't know if this was already mentioned, but I just saw a video of someone who made their own screens using a store bought screen, but instead of using emulsion she used her Cricut machine to cut peel-and-stick vinyl. She then adhered it to the screen and it functioned like emulsion would. She was screening on fabric, but I don't see whey it wouldn't work to screen onto tissue paper to make your own stencils. She could then peel the vinyl and re-use the screen for another design. I'm sure there are limitations to this method, but if you have a Cricut it seems like a good option. I'm going to give it a try if I can find the time.

[Callie Beller Diesel]

I remember doing a technique like that in my silkscreen class way back in the day, only we just used paper instead of cricut vinyl. You adhere the stencil to the outside of the screen, the part that goes against the thing you’re printing on. Flood the screen with your printing “ink” and adhere the stencil to the screen with that. It’s good for simple images and mono printing, anything that doesn’t need registration marks for subsequent colours.

[Babs]

5 hours ago, Callie Beller Diesel said:

I remember doing a technique like that in my silkscreen class way back in the day, only we just used paper instead of cricut vinyl. You adhere the stencil to the outside of the screen, the part that goes against the thing you’re printing on. Flood the screen with your printing “ink” and adhere the stencil to the screen with that. It’s good for simple images and mono printing, anything that doesn’t need registration marks for subsequent colours.

Yes , and can use same screen for other images

[neilestrick]

7 hours ago, Callie Beller Diesel said:

It’s good for simple images

With the sticky vinyl you should be able to do somewhat complex images since the entire image can be applied to the screen as single sheet. I think it probably depends on the quality of the adhesive on the vinyl, but it's available in varying degrees of stickiness, including some that are supposed to be 'permanent'.

[Babs]

1 hour ago, neilestrick said:

With the sticky vinyl you should be able to do somewhat complex images since the entire image can be applied to the screen as single sheet. I think it probably depends on the quality of the adhesive on the vinyl, but it's available in varying degrees of stickiness, including some that are supposed to be 'permanent'.

And some, try getting it off without wrecking screen! Remembering green coloured stuff from way back, needed a large trough to soak it off. Thinking now, prob be a solvent to get the goo off.

But as you write , way to go with complex stencil

[bny]

Low fire white cookie previously fired twice at cone 06 for reverse side decoration experiment, fresh Speedball Royal Blue underglaze modified with CMC powder and gum arabic solution, not dried down, Keoker ready-made screen, "half-ripe" xuan paper printed smooth side. 

Underglaze transferred and fired without overglaze at cone 06, then Mayco Crystal Clear overglaze fired again at 06.  No soap in transfer, just damp sponge, dry brush, wood tool burnish.

Previous tests had color softening and running in overglaze when overglaze was applied directly after printing, so I went with two firings.  This also allows any remnant paper fibers to burn away in the underglaze firing, reducing tedium and color damage in trying to clean those off.

I feel that CMC was sufficient to give printably thickened color without dry-down of new glaze, but gum arabic added alongside CMC gave less color spread and better image thickness at printing, and better color adhesion to the ware at transfer.  By look and feel, no measurements. Toothpaste consistency with a little gloss on the surface after a minute or two rest after mixing.

Preparation from newly opened jar underglaze, printing, and transfer to bisque can likely all be handled in a one hour instructional session. 

An instructional hobby studio with commercial bisque ware, or a classroom, would need only inexpensive screens and paper, and two safe materials beyond conventional underglaze.

Tools: plastic dish and wooden craft stick for color preparation, ordinary glazed tile as printing platen, commercial prepared screen, blue masking tape, plastic scraper, sponge, brush, smooth wooden burnisher.  Screens clean ok in slop tray water soak and rub then brief running water rinse.

Size reference: 61 mm diameter.  Conforming damp decal behavior gave transfer over and onto the edges, hinted at here.

Edited January 26, 2023 by bny

[Callie Beller Diesel]

For student work, you might not even need the gum Arabic and CMC. Commercial underglazes already contain some of those materials, and lots of tutorials out there just suggest leaving the underglaze to evaporate in order to thicken it to the correct consistency. 

[Ben xyz]

Thanks bny for thorough explanation and example - good detail.

[bny]

Just letting the underglaze dry down in the open is likely the best starting point, as long as it does not get so crusty that it cannot readily be mixed back to smooth toothpaste or thicker.  That has been my challenge with oven accelerated drying.  Amaco's videos show room ambient drying in a pie tin, and no additives, and their results look good with the designs and applications shown, emphasis upon bolder designs, and printing to slabs for tiles or before forming.

CMC is an admitted shortcut for using new underglaze from the jar.  It gives a good thicker consistency and is not difficult to add in increments and mix to uniform smoothness.  Note a video of Mayco screen printing additive as a mixing example.

The detriment is that all of the water from the original formulation is still there, diluting the color/ceramics and wanting to bleed and smear them under the screen and ruining both density and delineation.  Adding CMC slows this but might be impairing print density and transfer behavior, but as pointed out, there likely already is CMC in the underglaze.  Beginning with dried-down material helps (and I have at times used both oven and vacuum evaporation to accelerate).

Adding gum arabic alongside CMC (without dry-down) seems to improve print density and transfer behavior, but a test on a commercial bisque cup still gave very poor (unusable) transfer behavior by comparison to my fresh thirsty cone 06 fired low fire white cookies.  That same cup accepted a scrap from an old commercial transfer well enough.

Commercial transfers seem often to have a faint peculiar odor, somewhere between 60s elementary school tempera paint and old gym socks.  They have excellent density in the print, good release behavior from the paper, and better tenacity upon transfer.  That odor sparks alchemical intrigue, from which I will experiment.  Whatever's in there is probably less expensive than gum arabic, and works better.

[Ben xyz]

17 hours ago, bny said:

Just letting the underglaze dry down in the open is likely the best starting point, as long as it does not get so crusty that it cannot readily be mixed back to smooth toothpaste or thicker.  That has been my challenge with oven accelerated drying.  Amaco's videos show room ambient drying in a pie tin, and no additives, and their results look good with the designs and applications shown, emphasis upon bolder designs, and printing to slabs for tiles or before forming.

CMC is an admitted shortcut for using new underglaze from the jar.  It gives a good thicker consistency and is not difficult to add in increments and mix to uniform smoothness.  Note a video of Mayco screen printing additive as a mixing example.

The detriment is that all of the water from the original formulation is still there, diluting the color/ceramics and wanting to bleed and smear them under the screen and ruining both density and delineation.  Adding CMC slows this but might be impairing print density and transfer behavior, but as pointed out, there likely already is CMC in the underglaze.  Beginning with dried-down material helps (and I have at times used both oven and vacuum evaporation to accelerate).

Adding gum arabic alongside CMC (without dry-down) seems to improve print density and transfer behavior, but a test on a commercial bisque cup still gave very poor (unusable) transfer behavior by comparison to my fresh thirsty cone 06 fired low fire white cookies.  That same cup accepted a scrap from an old commercial transfer well enough.

Commercial transfers seem often to have a faint peculiar odor, somewhere between 60s elementary school tempera paint and old gym socks.  They have excellent density in the print, good release behavior from the paper, and better tenacity upon transfer.  That odor sparks alchemical intrigue, from which I will experiment.  Whatever's in there is probably less expensive than gum arabic, and works better.

A mystery to be solved - thanks for the investigation! Olfactory clues... In a book entitled "Graphic Clay" by Jason Bige Burnett, the author said he learned the following trick from ceramist Paul Andrew Wandless: add a transparent base (used for fabric and permanent acrylic inks) to the partially dried underglaze, which keeps the mixture hydrated longer and allows  the underglaze to stick to newspaper when screening, while permitting the ceramic material to to absorb moisture and release itself from the paper. Something perhaps to try.

[neilestrick]

The smell may come from the preservatives they use. All commercial glaze products contain a biocide to preserve the gum, and each company seems to use a different one, because each brand has a different odor. The underglaze transfers that are made by hand in the US use commercial underglazes, often the Amaco Velvet line.

[bny]

I have been experimenting, and having good results with underglaze finer-detail screen print impression and transfer with two additives: yellow dextrin (dry powder) alongside gum arabic (dry powder now rather than bottled solution).  Both ingredients are safe but are nutrient materials that could spoil if not dry.  Partial drying of the underglaze helps to reduce bleeding in the screen impression, and to get ink that stands on the paper.  The two gums help it to stand on the paper, bind to the ware, yet unbind more readily from the dampened paper.  My current guess is that gum arabic both helps standing and binding to the ware, and that dextrin both helps standing, and loosens more rapidly with dampening to facilitate transfer.

Yellow dextrin is an industrial paper and fabric sizing and adhesive.  It is available in smaller quantities from a few sources, mostly offered as a composition binder for fireworks.   The good news is that you can make your own yellow dextrin by roasting dry corn starch in the kitchen oven.  Old industrial recipes suggest around 320 F / 170 C, but I have had better results around 375 F / 190 C by uncalibrated oven dial.  I let it roast for a few hours, with interruptions, testing occasionally.

Final result should be a yellowish buff color comparable to corn flour.  Mine is a bit lighter than the commercial product, but might benefit from hotter or longer roasting.  You are breaking the starch down into something more soluble: like old-school envelope and stamp glue.  Test by placing some in a dish, add small increments of water, and mix with a fingertip.  After some work you should get a yellow (mine so far) to brown (commercial dextrin) slippery goo that will readily coat the dish, become tacky, then dry to a uniform film, like envelope flap glue.  Also it smells quite appetizing.  Do not allow yourself to imagine delicious underglazed donuts.

I don't have a quantified recipe yet.  Starting point was 7 units of gum arabic to 5 units of yellow dextrin, but I don't have a ratio to underglaze, or an initial dry-down factor.  All I can say now is gloss-surfaced toothpaste consistency, and that I usually add gum arabic beyond the initial amount, until it looks and feels "right", and proves in a print and transfer.

If anyone is aware of a small quantity source for the darker, more deeply pyrolyzed starch sizing/adhesive called "British gum" please let me know.  Easy to find in container loads from India, not so easy otherwise.

Experimenting with papers, in addition to half-ripe xuan previously noted, has brought good results with two papers thinner than the xuan. 

First is Yasutomo hanshi calligraphy practice paper, nearly tissue-thin, which looks like a machine glazed (MG) paper.  One side is nearly shiny, and the other is dull.  This gives good impression and transfer, and may be a better choice than xuan for curvatures.  The wet strength is sufficient to safely pull a screen print (I oven dry and the print goes very waffle-crinkly), but sponged application requires care.

Second, surprisingly, is dirt-cheap smooth (not creped) medical examining table paper (also has MG surfaces). I gave up on this immediately for hot oil intaglio transfer years ago, because it did not survive the soap sizing needed for that process.  It is just good enough, however, for this process, and I already had plenty.   More fragile than xuan or hanshi, but readily available and economical.  Results may vary.  I spoke to a converter/wholesaler some time back, and he cautioned that this paper varies more than some due to price-driven commodity sourcing.

Hanshi peels more cleanly than exam table paper; xuan peels more cleanly than hanshi.

In this round I have been using Speedball and Amaco Velvet underglazes, both with good results.  A cookie cutter, Amaco Radiant Red, and a commercial hearts screen, have given  quick cute not-identical  Valentine charms that have brought exclamations, smiles, and even tears from recipients.

 

 

[PeterH]

>If anyone is aware of a small quantity source for the darker, more deeply pyrolyzed starch sizing/adhesive called "British gum" please let me know. 

May be of relevance.

Pyrotechnics data for your hobby: Dextrin
https://pyrodata.com/chemicals/Dextrin
Sources:
Dextrin is easily prepared from starch. Potato and cornstarch will both work fine. The starch is spread out on a sheet in a layer about 1 cm thick and placed in the oven. The oven is then heated to 220°C(400°F) for several hours. The dextrin will turn slightly yellowish brown. One way to check if all the starch has been converted is to dissolve a small sample in boiling hot water and add a drop of KI3 solution (Lugol's iodine solution). A blue colour indicates presence of starch, which means the conversion hasn't completed yet. KI3 solution is conveniently prepared by dissolving a crystal of elemental iodine in a potassium iodide solution.

The complete removal of starch could be important in your application, so I would try the starch-iodine test.

PS
Dextrin and Making Dextrin
http://www.wichitabuggywhip.com/fireworks/dextrin.html
 

Edited February 8, 2023 by PeterH

[PeterH]

Dextrin is readily available from small-scale pyrotechnic ingredient suppliers (if you can find them). My limited experience of these (looking for pottery ingredients) suggests that they are fairly cheap and very technically savvy.

But I've no real idea how to assess the "quality" of the dextrin they supply (other than it's suitability as a firework ingredient).

US example https://www.fireworkscookbook.com/product/dextrin/

I suppose that you could try asking them for advice.

[bny]

The time/temperature table is very useful, thank you.  I have not been using a catalyst, though AlCl3 solution should be on the way.  It's good to see how far it can go without lab chemicals, but I have been planning to try AlCl3.  Hypochlorite (mentioned in an old patent) gave a crusty useless mess.

[PeterH]

49 minutes ago, PeterH said:

US example https://www.fireworkscookbook.com/product/dextrin/

... and even if it's only "yellow" dextrin it would probably be a better starting point than cornstarch for your own processing.

[bny]

I have had improved results by transferring onto a layer of unfired underglaze, rather than directly onto the bisque fired piece. 

Others have noted success with only drying down of the pattern underglaze "ink", without additives.  I never had good results with that directly on bisque, but the smaller butterfly piece in the photos is Amaco Velvet Amethyst dried down some, and applied over a background of Amaco Velvet Lilac toned way down with their White.  Hasty rough layer of Mayco Crystal Clear overglaze.

The larger shell piece uses the same underglazes, but with yellow dextrin and gum arabic additives in the ink.  I am pleased with the definition and density.

Both were printed from polymer clay decorating screens from Amazon sellers.  Both used Yasutomo hanshi paper. 

I have found that warm water might help transfer onto an underglaze layer.  I dab the transfer on sort of radially outwards, dress the edges down, then press a not too damp sponge onto the whole surface for a few seconds.  Then burnish with a polished wooden knob tool through a piece of old cotton knit T-shirt.  Then apply a damp sponge again, let rest a moment, burnish again through a second piece of cloth, then peel the paper. 

Hanshi does not always peel cleanly but it gives the best definition so far.  I peel and rub gently.  If entirely clean, overglaze can go on, usually gives a softer result.

If not entirely clean, I fire at cone 06 then apply overglaze and fire again.  This often gives crisper definition than applying overglaze over the unfired pattern.

Hanshi is a bit fragile for applying to complex curvature, so I have been working with various other papers bought years ago for another project.  Wet strength tissues sold for book and art restoration, usually abaca fiber, are showing some promise.

I had one partially good result on a small demitasse cup, compound curvature, using a wet strength tissue sized before printing (paper surface is not smooth, essentially a more finely textured teabag, so inking is uneven).  I sized it with homemade "British gum", which is just the homemade yellow dextrin roasted darker, sponged on and partially dried on recycled polyethylene Amazon envelopes.  Peeled at the right time, handled carefully, then dried on an open screen, one can get a nearly glazed paper surface.

Edited March 4, 2023 by bny
Clarify identification of photos

[Marthaaleo]

Why the gum arabic and dextrin?  Thickeners?

[bny]

2 hours ago, Marthaaleo said:

Why the gum arabic and dextrin?  Thickeners?

Yes, thickeners that I feel offer specific characteristics.  Gum arabic is less soluble, helps the ink to stand on the paper, and to adhere to the work.  Dextrin also thickens, and is more soluble than gum: I feel that this may aid release of the design from the paper.  Recall old-style postage stamp and envelope flap glue.

With a little too much gum arabic, the ink can get rubbery.  A few seconds in the microwave and a quick stir, softens it nicely and can give better printing behavior (warm flow through screen, cool set on the paper).  That's more alchemy than systematic observation, though.

I tried adding CMC gum and found that it thickened the ink but was apt to give a smeared print and poor transfer, likely redundant with CMC in the underglaze already.

 

[neilestrick]

I spent a couple of hours yesterday morning running some screen printing tests. I'm using a 110 mesh screen, Speedball underglazes, and raw Xuan paper. My findings:

- Speedball underglazes come fairly thick in the bottle, so with no modification they actually print pretty well for 1-2 prints. However, by the third print the underglaze would stop going through the screen and it would just print water. The thicker the underglaze the worse it got. If I washed off and dried the screen, then it would print again. I think the underglaze must be sealing up the screen.

- I don't have any guar gum or dextrin in the studio, but I do have CMC gum and Veegum T, which together are fabulous for suspending glazes and making them brushable. Typically I would make a syrup out of them, but I didn't want to add too much water to the underglaze so I mixed it up like thick snot- 2 tablespoons of CMC and 1 tablespoon of VGT to 1 1/2 pints of hot water (normally would use 1 gallon of water). Let it soak (overnight if you have time), and mix it with a stick blender.

I added 1 teaspoon of the snot to a pint of underglaze and ran a dozen prints without any problems. I also thinned out the underglazes a bit and was much happier with the thickness on the paper. No need to let them stiffen up at all. In fact, Speedball underglazes are a bit too thick in the bottle. I'd seen people say it should thicken up to a toothpaste consistency, but I didn't find that to be necessary or desirable.

- I was concerned that the CMC gum would make it more difficult to transfer, since in a typical application the gum makes the underglaze hard and resists water (which is why I always recommend applying underglazes to leather hard and bisque firing before glazing if you're working with dipping glazes). With the transfers they worked much, much better with the added gum. Great release from the paper. I lay the transfer on the leather hard pot, dab it with a wet sponge, then lightly roll it with a little brayer.  I'm doing some bold patterns, not thin line work, so it's easy to control how complete the image transfers by how long I leave the transfer on the pot.

- The raw Xuan paper is very fragile when wet. You have to be very careful about rubbing it when it's sitting wet on the pot. I've got some half raw coming and I'll see if that holds up better.

EDIT: Forgot to add- I have tried making the transfers with newsprint before, but I don't like how much the paper wrinkles as it dries. The underglaze was also more likely to flake off when dry. I'll try it again with the new gum-added version later this week and see if it behaves any better. The good thing about the newsprint is that it's much more durable than the Xuan paper.

[bny]

With the pre-made fine detail screens that I am using, I can sometimes get an acceptable second print without cleaning the screen, but this is the exception.  I wash and finger-scrub the screen in my slop bucket, then briefly in running water, then dry it before making more prints.

Agreed that Speedball underglazes can work well, and start more viscous than most of what I see with Amaco Velvet.

Half-raw (aka half-ripe, refers to sizing treatment) xuan has behaved well for me, though Yasutomo hanshi paper is thinner and transfers more readily, and remains my first choice for flat pieces, though it usually leaves fibrous residue.  Clear overglaze is not reliable over the residue, so I fire the underglaze base and design, then clear glaze and fire again.

I work with bisque fired pieces, only a couple of tries with leather hard.  As previously noted, I have better transfer results onto a layer of underglaze, than directly onto bisque.

Carnival Papers (UK) offer a wet strength tissue used by hobbyists for something called "willow lanterns".  It is 17 gsm thin, has remarkable wet strength and a smooth surface, and peels cleanly, but it is difficult to get a good transfer (ink wants to stay on the paper).  I have been experimenting with "British gum" (darker roasted dextrin) sizing on this in hopes of getting something like decal slide behavior, with maybe a little improvement.  This paper is less permeable.  Hot water then a couple of days cold soak test, and the paper stays intact, perhaps too much so.

I have had usable but not yet excellent results, with British gum sizing on a wet strength "facing tissue" (art/book conservation) sold a few years ago by Talas.  I don't see it in their current online products list.  The wet strength is excellent and it is softer (less crisp, easier to conform) than the Carnival paper.  This tissue has a more open surface and lay than xuan or hanshi, with substantial ink passing through to a newsprint backing sheet when printing.  Sizing helps this, but more experimenting is needed.

Lens tissues sold for conservation have given poor results.  A thinner wet strength tissue (old purchase from a defunct small online shop) that might be 9 gsm "Tissutex" is next on the sizing experiment list.

[Ben xyz]

A lot of great and useful info - thanks! Am about to purchase a couple 110 mesh screens as advised. Interesting that the speedball underglazes 'as is' tend to work best (even better with the 'snot'). When applying onto leather hard clay (flat surfaces), was going to use spray starch after to avoid smearing when handling/assembling the sections (though would have to avoid/mask edges so they could still be attached and stick to each other). There'll be a learning curve. Will check out YouTubes for this clay screening process.

Also interesting to learn that underglaze transfers work best on underglazed surfaces (I think I have that right), rather than bare ceramic surfaces. Thought it might pick up/dissolve  the pre-underglazes. Or do I apply underglazes onto greenware, bisque fire, then apply the underglaze transfers? Will re-read and likely figure it out. Thanks again to you both!

 

[neilestrick]

1 hour ago, Ben xyz said:

Also interesting to learn that underglaze transfers work best on underglazed surfaces (I think I have that right), rather than bare ceramic surfaces.

On bisqueware, yes. On greenware it works fine right on the clay.

[neilestrick]

2 hours ago, bny said:

Carnival Papers (UK) offer a wet strength tissue used by hobbyists for something called "willow lanterns".  It is 17 gsm thin, has remarkable wet strength and a smooth surface, and peels cleanly, but it is difficult to get a good transfer (ink wants to stay on the paper)

Do you roll it with a brayer? That seems to be the key with the rice paper I've been testing.