thermofax printing tutorial

Supplies for thermofax printing

Use and care of your thermofax screen.
Preparation
Your screen may come with a plastic frame - the edges can be taped with duct tape placed on the frame and covering the edges of the mesh on both sides, making sure the tape doesn't cover any of the design. This step is not strictly necessary but it does make the screen easier to clean. If the design comes too close to the edges of the frame, you won't be able to tape it.
framed screen with taped edges
If the screen doesn't have a frame the edges need to be strengthened either by taping or painting with acrylic house paint. For printing, the screen can then be taped to a traditional silkscreen in the same way you would use any other type of stencil or used on its own, placed directly onto fabric.
unframed screen with tape
It's a good idea to mark the front of the screen so you know which way up on the fabric to place it. The mesh has a right side - if you feel it, you will find that 1 side has a textured or slightly rough surface while the other side is smooth. The smooth side is more fragile so that side should go against the fabric. the stronger rough surface faces up and is the side that the squeegee scrapes the paint across.
The screen can be reversed if you want to print an opposite image but it will break down more quickly if you usually print on the wrong side.

Squeegees (pic above)
A small, light scraper or squeegee works best. I use a baking scraper or similar, even an old plastic loyalty card can do the job. Obviously, the squeegee has to fit within the frame. Some people use a foam brush or roller. It's a good idea to experiment with some of these to establish what works for you and the effect you want.

Printing Media
You can print with Permaset fabric printing ink or other thick textile paints as well as thickened dyes or discharge paste. Be careful if using acrylic artists paints or Lumiere - these dry more quickly than textile paints and if they dry on your screen, the mesh will be permanently blocked. Open acrylics would be better, or add a suitable medium to extend drying time.
thermofax printing workshop
Printing Surface
To make a good print surface, tape down 2 layers of acrylic felt onto your table and top with a layer of calico, cotton sheeting or similar which can be washed when necessary. Tape or pin your washed and ironed fabric to this and you are ready to print.

Printing
Do a test print first so you know how many pulls you will need. This varies with the thickness of paint and the type of fabric. 1 or 2 pulls should be OK.
Position your screen on the fabric for the first print. Have your squeegee ready - it must fit within the frame - and paint mixed.

Spoon or pour a line of paint across the top of the screen mesh. Hold the squeegee at an angle, not far from upright, in 1 hand, while holding the screen in place with the other hand and use the squeegee to pull the paint over the design, towards you. Use the squeegee to scoop up left over paint at the end of the pull so you can do another pull if needed. Keep the paint loaded squeegee over the screen so it doesn't drip onto the fabric. Re-position your screen for the next print and add more paint if necessary.
If your next print will be close to the previous one, you may get paint on the back of the screen which will end up on your fabric in later prints. This is called ghosting and can be avoided by placing a piece of scrap paper between the wet print and the screen. But if you're printing an all over texture design, ghost images may not matter to you.

You can continue printing until your fabric is covered, but don't allow the screen to sit for long with paint drying on it, especially in hot weather - its better to wash it out. It will dry quickly, and you can continue printing.



Cleaning the Screen
Wash the paint off the screen as soon as you finish your print run - gently, under cold running water with a soft sponge. I use a paintbrush to clean any paint from under the edge of the frame. (Only necessary if its not taped around the edges) Sometimes the paint will stain the mesh but that is not a problem. You can see if the mesh is clean by holding it up to light and making sure the design areas are not clogged. Dry the screen btween 2 layers of towel or stand to dry (not in the sun or near a heater)

A cat litter tray with some water in it, is handy to have nearby your printing area. When you finish printing scrape excess paint back into the jar and place screen into the water until you're ready to wash it. Also, have sheets of newspaper in case you need somewhere to quickly put down the screen or squeegee between prints.

Setting the print
When the printed fabric is dry, it can be heat set by ironing so it will be washable (instructions should be on the paint label) Thickened dyes are set by batching or steaming (depending on the type of dye), deColourant discharge paste needs steam ironing to remove fabric colour (wearing a respirator to protect you from any fumes).

Store screens upright, away from heat or direct sunlight. Unframed screens can be kept in a manila folder.

workshop printed fabrics


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