Mesh preparation is the easiest, cheapest and quickest way to improve screen life. This helpful How-to Guide will show you the best way to maximize stencil adhesion, which will save you time and money by reducing or eliminating the need to remake screens that break down on the press.
The importance of mesh preparation
Polyester mesh is the most commonly used mesh today because it's resistant to most screen chemicals and it doesn’t absorb water or change tension during use. However, untreated polyester fibers have a very smooth, hydrophobic surface. Inks and solvents deposit greasy residues on this surface, making it very difficult to get water based stencils to adhere properly. The solution is effective mesh preparation which helps the stencil adhere to the surface of the mesh.
What should a prepared screen look like?
Luckily, that's easy to see. A well prepared screen should be able to hold an even film of water as seen in this picture, where the right hand side was prepared with Universal Mesh Prep. A quick and simple test can tell you how well prepared your screens are - we call it The Mesh Prep Challenge.
The Mesh Prep Challenge
The Mesh Prep Challenge is a simple 3 step test that will quickly demonstrate just how well prepared your screens really are. Take a look at how well the Universal Mesh Prep handled the challenge and compare it to your product.
- Prep half of your screen as usual
- Rinse it with a water spray
- See how much water it holds
Degreaser or mesh wetting agent?
MacDermid Autotype offers two types of degreaser Auto Degreaser Concentrate and Universal Mesh Prep. The Auto Degreaser Concentrate range is diluted with water prior to use, so 1 liter of concentrate can make up to 50 liters of degreaser solution.
The concentrates work brilliantly for PLUS direct emulsions; however, if you're using Capillex screen film, we recommend Universal Mesh Prep as a combined degreaser and mesh wetting agent. This helps the mesh to hold as much water as possible which is the key to applying Capillex successfully.
Top tip: To save time, always degrease the mesh after decoating the previous stencil. Then store the screens covered so they don't become contaminated again.
The Brush Pump is an excellent tool for use with the Auto Degreaser Concentrate. Add 1 liter of the 1:25 product to the 25 liter drum and then top up with water. Simply moving the brush up and down the screen will activate the syphon pump and apply just the right amount of the degreaser solution to the mesh.
No air or electrical supply is needed to operate the Brush Pump so installation takes seconds.
If you are using Capillex or an indirect stencil film such as Five Star, then it is important to abrade/roughen the mesh as well as degreasing it. This will ‘key’ the smooth mesh fibers allowing the stencil to adhere better. This picture shows the level of micro-abrasion that ‘keys’ the surface without damaging the fibers
Top tip: Abrade all new screens and after every fifth stencil to get the best results.
This ready to use micro-abrading liquid is simply applied to both sides of the wet screen with the Autotype Brush for a perfect result. The Autotype Brush has soft, chemically resistant fibers to give the maximum effect without damaging the mesh. Can be used with Auto Degreaser Concentrate solution, Universal Mesh Prep and Autoprep gel.