Difference between revisions of "Equipment/Screenprinting"

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Screenprinting area

Summary

Screenprinting is a manual printing technique using liquid ink and a stencil to create permanent images on sheets of paper, card or fabric or pre-existing items such as t-shirts and cotton shopping bags. Due to the work required for set-up and clean-up, the process is most suitable for printing multiple items such as set of identical t-shirts or posters.

A screen is a frame with a fine polyester mesh stretched across it. The mesh carries a stencil which is printed with liquid ink/paint in one colour at a time using a squeegee. The stencil on the screen-mesh works in a similar way to stencils in other art processes: some areas of the screen are left open and others are blocked. This determines where ink is deposited onto the piece and thus creates a design or image. The result is a thin film of ink applied to the workpiece. There are many ways to create stencils.

There are three main steps to the process.

1. Create a stencil and attach it to the screen (or use a screen with stencil prepared previously)
2. Print things
3. Clean up screens and tools immediately and reclaim ink where possible
4. Pay for any Makespace materials used (paper and ink)

Owners

• Jo Brook
• Matthew Taylor

Training

See owners for occasional demos.

Warnings

Waterbased screenprinting does not have serious hazards but without due care the process can permanently damage various items in the space, including yours (or others') clothes, workpieces and also inconvenience other screenprinters by making screens unusable.

• Screenprinting ink will stain clothes, since it is designed to dye fabric permanently. So wear an apron while printing and pay attention to stray bits of ink, wiping hands and equipment if needed
• Ink is liquid so work with care not to let splashes of it get onto other people's work.

This applies especially when washing the screen out as the diluted ink can still stain and is more likely to splash than when the ink is in its print thickness.

• Wash out the screen immediately after the last item has been printed. Waterbased ink starts drying into the screen as soon as you are not actively printing to force new ink through the mesh. This will help shared screens to be ready for the next user.

House Rules

Waterbased screenprinting does not have many safety issues, although take care when reversing the platen for t-shirt printing as it is solid. The facilities are shared and the printing area is small so there are some house rules for using this equipment.

Ink / paint

• Makespace supports waterbased printing only, whether you are using Makespace shared equipment or some of your own.

So do not use any inks, paints or varnishes which cannot be removed from the screen using just water and washing up liquid. (Non-waterbased printing is offered by some of the specialist printmaking studios in Cambridge.)

• You may bring in and use your own ink if it is waterbased. If it is not one of the inks already in stock, check the procedure for bringing chemical products into Makespace: Hazardous_Materials. Most suitable inks will be the ones which don't have hazard warnings. If in doubt about ink, ask the owners or on the forum before using it in Makespace.

Screens

Makespace has a small number of shared screens which are intended for short-term use and learning.

This means that:

• No permanent stencils should be applied to screens. These are only usually needed for print runs in the 1000s of items.
• You should aim to finish your printing in one session if possible and remove the stencil at the end.
• For large print runs and longer-term use, we recommend buying or making your own screens.

Equipment

Screenprinting frame:

• Hinge clamps to hold screen during session
• Reversable bed with:
  • Hinged platen for printing larger t-shirts, tote bags etc. (Pull t-shirt over platen to stop ink printing through to the back layer)
  • Flat surface for printing onto paper and other single-layer materials

Print-drying rack 20 spring-loaded A2 wire shelves

Plan chest A1 primarily for storage of papers and flat items. Currently in use for screen-drying until a dedicated rack is constructed.

Screens outer w x h (max printable area w x h) Thread-count: Approximately 28T

• 1 x 31cm x 32cm (21cm x 22cm)
• 2 x 45cm x 58cm (35cm x 48cm)
• 3 x 56cm x 77cm (40cm x 60cm)

Squeegees

For textile printing D or V-profile blades are used, in order to lay down extra ink as some is absorbed into the fibres:

• 1 x 8" (20cm) width, V-profile blade
• 1 x 12" (30.5cm) width, V-profile blade
• 1 x 15" (38cm) width, round profile blade

Paper/other non-textile printing uses square-profile blades which lay down less ink and give a sharper print:

• 1 x 8" (20cm) width
• 1 x 12" (30.5cm) width

Other small tools:

• Palette knife (for transferring ink to/from the screen)

Protective clothing:

• Printer's aprons (2)

Stock

Supplies

• Unprinted newsprint paper, A2+ sheets (50x70cm)

For test printing and creation of paper stencils (using manual cutting or lasercutter) This is not considered paper stock as it will yellow in sunlight and is thus not suited to making finished products

• Washing-up liquid

Inks/paints

• System 3 Acrylic print medium (paper/general use)
• System 3 Acrylic print medium (fabric)
• System 3 Acrylic pigments for colour mixing: Black, white, yellow, red, blue
• Pre-formulated fabric inks (e.g., Permaset Aqua Fabric Magic) in a few basic colours

Papers

• A2+ 250gsm printing paper. £1.30 per sheet.

Set-up items / wishlist

Workbench, drying area and storage

• Adjustable-height bench (as in craft room but somewhat deeper) -- 2 x Finnvard trestles or sheet with screw adjusters (found)
• Space to store screens -- can be a vertical space, also under the table

Small tools and accessories

• Hose for tap to help with screen washout

Issues to be resolved to commission

• How to charge for materials Suggestion is to charge for paper by size rather than ink.

Stencils made on the vinyl cutter would be charged as for other vinyl cutting.

• Methods to Allow/Support
  • Printing methods
    • Allow only Water-based printing -- oil-based methods require toxic products, specialist disposal, ventilation etc.
    • Allow printing using any screens which have stencils compatible with water-based inks. This includes photo-stencils created offsite.

• • Stencil-making methods

The following dry stencil-making methods will be trained or recommended:

• Paper-cut stencils

Using the thin newsprint paper provided, stencils can be made by manual cutting (or tearing) using scalpels or scissors. For trained users, lasercutting can also be used.

• Vinyl-cut stencils

Based on trial sessions, recommend using vinyl on the squeegee side for durability of stencil. Needs care when weeding especially on small details and lettering.

Note: We cannot reliably support photo-stencil creation, mainly because it requires a space which is guaranteed to be dark during the exposure. A small darkroom or walk-in cupboard would be needed for this, and a light-safe screen-drying rack. If there is demand, this is something we could think about, maybe for the future space.

• What classification?

Safe enough to be green but maybe should be orange as would like opportunities to make people aware of good practices to avoid wastage and ruined screens when sharing the equipment. Posters above the area would be useful to remind people to washout immediately after use etc.

• Training session formats

Probably need to run sessions focusing on either fabric or paper printing. If trainees need to demonstrate their learning then sessions will probably be 2-3 people for around 3 hours.

• Storage of screens during work in progress Printing several colours may take longer than one session, as each colour needs to dry. So a user should label their screens with a name and date on masking tape. The policy on re-using screens could be similar to the private stock cupboard.

RiskAssessment