One very common question that a screen printer might find themselves asking is, “Do I need a pressure washer?”
If you’re just starting out, odds are you can get away with just a high pressure faucet in your home. Many DIY printers start this way. However, if you’re getting to the point where you are reclaiming a lot of screens, you may want to consider a pressure washer. We suggest one capable of at least 1200psi, though 1600psi is the most common.
Virtually all emulsion removers will give far better results with a pressure washer to blast away the loosened emulsion. The screen should be positioned with the top edge up against the back wall of your wash sink, at an angle that provides solid support. It has to be able to stand up to the blast of the pressure washer without being knocked over. You’ll want to apply your emulsion remover to both sides of the screen, scrubbing it in circles with your scrub pad. Once the emulsion looks like its starting to loosen up, its time to put on the pressure.
Be sure the print side of the screen is facing you. A high pressure spray directed at the squeegee side of the screen can hit the inside edges of the frame and ricochet. The point where the mesh meets the inside edge of the frame is also one of the most vulnerable points on your screen—really the last place that ought to be hit with a high pressure jet of water.
Both the power and the width settings of the spray can be adjusted on most pressure washers. You don’t want to concentrate a lot of power in a small area, so a fairly broad spray works best. Sometimes it’s hard to remember how the spray was adjusted the last time the pressure washer was used, so get into the habit of aiming the wand away from the screen when you first pull the trigger. A very narrow spray delivered at full power can blast right through fine meshes. A wider spray will almost always serve you better, unless you have small spots of old, hard to remove emulsion. In these cases, using a narrower, stronger stream around the edges of the problem areas should work, as if you are using the water to ‘scrape’ the emulsion spot away.
One mistake many printers will make when they first introduce a pressure washer into their shop is using a strong, concentrated stream on freshly exposed screens. While you want to be wary of too much concentrated pressure when reclaiming, it is especially important with a screen just off the exposure unit. When you’re rinsing out your design, slow and steady wins the race. Turn that pressure washer’s power down, widen the spray, take a step back, and take your time with it. It’s important to keep in mind that your emulsion is pretty soft at this stage, so too much pressure and you risk knocking out your design’s edges or finer details, forcing you to reclaim and start all over.
Once you get comfortable with best use practices and adjusting the settings as necessary, you’ll find that a pressure washer can be a screen printer’s best friend in the dark room. Instead of spending all of your time trying to reclaim your screens, blast them with your pressure washer and move onto the next job!
Ryobi 1600 PSI Electric Pressure Washer