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Screen Printing onto Clay

Place your own designs onto clay, repeatedly at a low cost, using a simple technique - with RISO ScreenMaster it's easy.

The screen used for this process is RISO ScreenMaster 70 Mesh. RISO ScreenMaster is a combination of screen and stencil [polyester screen and saran film], with a coated [shiny] and uncoated side.

The design is imaged onto the screen by using a NEHOC Screen printing or Ceramic Printing Kit, PRINT GOCCO PG-5/ PG-11/ PG Arts/ B6 or B5 model, RISO SP-275 ScreenFax, Vistafax Thermal Copier [or similar] in a flash!

Let's explain the process of placing a two colour design onto clay, starting from a single piece of artwork/drawing

Producing your artwork

To gain the two colour separation, the artwork must be colour separated. After drawing or copying a suitable design, fix the original piece of artwork onto a light box [or similar]. Overlay a new sheet and trace all areas to be printed in the first colour from the original - creating your new piece of artwork. Overlay an additional sheet and trace the second part of your design

You now have the two colour separation artwork.

Remember that you MUST completely colour in areas black that you wish to reproduce as a solid area - DO NOT leave as a line drawing [unless desired].

Lay the completed tracings on top of the original and check for areas which may have been overlooked.

Preparing the Artwork

It is preferable to use photocopies for the 'imaging artwork' rather than carbon pen, because the original tracings can be kept for future use.

When access to a photocopier that will enlarge/ reduce the design is available, a single set of artwork can be used to reproduce a range of sizes i.e. dinner & bread plates.

Place the design onto the photocopier stage and copy at the lightest setting available before the design begins to lose quality. Even the lightest setting is enough carbon to image a screen - too much carbon can block the screen and create problems with very fine designs or solid areas. [see Artwork Clean-Up Information Sheet to cure such problems]. A light setting will also help eliminate 'spotting' that naturally occurs in some photocopiers due to age/ general use

After you have copied your design, check for 'spotting' or other unwanted marks. NB: If you touch up the design with correction fluid/ pen/ etc - YOU MUST MAKE A NEW COPY.

If the marks can be cut out by knife or scissors than do so - you will not need to make a new original.

NB: Ensure cuts are no closer than 2mm to edge of design.

Creating your screen

• Using your photocopied designs, image against the coated [shiny] side of the mesh on a PRINT GOCCO or previously mentioned thermal copier as per the models instructions

• Repeat the process for the second part of the design

• Place the plastic frame mounts on a flat surface, tape upwards, and remove cover from tape

• Mount the imaged screens onto the plastic frame mounts as per standard procedure - Instructions for this are readily available. Ensure that the screen has no ripples but is not too tight/ buckled [the frame will bend] as over tightening may distort your image

• Remove your artwork and your screen is ready for use

Preparing the clay

The surface must be absolutely flat- Using a rolling pin, flatten the clay to the desired thickness/ shape/ etc.

To avoid humps in the middle of the slab, roll top to bottom, side to side, corner to corner - keeping the rolling pin dry and clear of any clay particles.

The flexibility of the RISO ScreenMaster and frame allow a slight give, to reach dips and low spots, however it is quicker and much easier to begin with a flat surface.

A little time spent in preparation will help ensure a great result.

Preparing the colourants

• Combining any fabric printing reduce [water based] as a medium and powdered underglaze colours, make a fairly thick paste - peanut butter consistency

• For stoneware, inks can be made using oxides for colourants and the same printing paste

• Pre-mixed colourants may also be used for the printing process

Preparing to print

When the slab is prepared, have ready . . .

• Brushes - one for each colour, fairly stiff bristle

• Pigments - ready mixed

• Screens stacked in order of use

Positioning the design

It is helpful to have the area for the placement of the design on the clay marked in some fashion,a light scratch with a pin just outside the desired area, sufficient to be seen THROUGH the screen, is one method.

NB: As soon as the first colour is laid down the scratch can be lightly smoothed over.

Printing the first colour

• Dry the area to be printed with a hair dryer and place the screen down immediately

• Using a brush, apply sufficient colour to cover the design area - no need to waste ink on unused areas of the screen!

Make sure no part of the design is missed - it is best to check by holding one side of the frame and gently lifting the other side [in a hinge action], checking as you lift.

If there is one, lower the screen immediately and brush the area - repeat as necessary.

Registering the second screen

• After lifting the first screen, dry the area with a hair dryer ready for the next colour

• Registration of the second screen is done by looking through the screen while gently lowering it into position

For additional screens/ colours, repeat this registration process as required.

SPECIAL NOTE

When working with WET clay, it is not always necessary to mount the RISO ScreenMaster to a frame, as the ScreenMaster bonds sufficiently to the wet clay.

It is important however to adjust the size of the ScreenMaster to fit within the clay shape. This will prevent it from curling over and marking the clay surface.

IMPORTANT

When using fabric printing paste, the screened piece MUST be bisqued AFTER screening and BEFORE glazing to burn off the paste.