Although most print shops consider reclaiming screens a mundane, less skilled job, it’s one of the most important steps in screen printing. Many of the issues that print shops have with screens can be resolved at the reclaiming process, and taking the time to properly reclaim screens improves productivity and results in a better final print.
CHECK THE EQUIPMENT
Let’s start with the equipment. Many screen print professionals use a home-grade electric power washer they bought from the local hardware store. These power washers are typically 1400 to 2000 psi and are meant for occasional household chores, such as cleaning the driveway and washing the car.
These machines lack ample pressure and aren’t meant for daily use, six to 12 hours per day. They eventually burn up and are typically replaced every six weeks to six months. Although these machines are only about $100, it’s less expensive and more efficient to buy a commercial power washer, which costs around $700 and is built for everyday use.
Along with using a good-quality pressure washer, it’s important to use a backlit screen booth when reclaiming. Again, don’t skimp on cost and purchase a booth without some sort of light fixture mounted to the back. The reclaimer should be able to clearly see while working. Without a backlit booth, the reclaimer can easily overlook small pieces of emulsion and other contaminants that may be left in the screen.
KEEP A CLEAN SHOP
The cleanliness of the screens and booth has a serious effect on the final stencil, as well. I’ve visited numerous shops where you can’t pick up a screen without getting ink all over your hands. Not only will this ink eventually leave fingerprints and smudges on the final print but it also causes contamination in the degreasing process. To avoid this, wipe down the frames of the screens before stripping away the emulsion and consider cleaning the inside of the booth during the last 10 minutes of each day. If the frames and booth are both full of ink, tape, and residue, there’s a good chance the reclaimer will recontaminate the screens during the degreasing process when all of that grime is blown around in the final rinse.
I find that a three-part process works well for cleaning. The process includes first breaking down the ink, then removing the emulsion, and finishing with degreasing. Start by scrapping any excess ink that was left behind by the printer. After that, spray the screens with an ink degrader, scrub both sides of the screens, and then rinse with a power washer.
Next, strip the emulsion from the screen. We use a concentrated chemical that recommends a mix of 25 parts water to one part emulsion remover. However, we want to reclaim as many screens as possible each day, so we actually only dilute the mix 10 parts water to one part emulsion remover. At this rate, one person can effectively reclaim 100 screens in an eight-hour shift. Once the emulsion is stripped, we scrub both sides of the screen with a high-quality degreaser. After rinsing again, the screen is ready for storage in an environment free of dust and other potential contaminants.
If a “ghosted” image is embedded in the screen, you should also use a dehazer. Essentially, a ghosted image is stained into the mesh. This can affect your final stencil and should be removed. But don’t regularly use a dehazing agent because it’s a harsh chemical that can shorten the life of the mesh.
If any of the three processes are skipped or performed incorrectly, excess pinholes can appear in the final stencils. Typically, degreasing is the culprit. Be sure that the screens are degreased properly and rinsed thoroughly, which will most likely take care of the pinhole issue. Reclaiming screens may not rank as the most glamorous side of the process, but it goes a long way in rewarding your shop with better prints and a more efficient business.