Screen printing guru Colin Huggins went live on YouTube to chat about common reclaiming issues. If you've ever run into cleaning locked up screens or screens that won't clean properly, this is the video for you.
PROPER SCREEN EXPOSURE
In the video, he first addresses how to properly expose your screens because it'll affect your reclaim process. When exposing screens, you need a 21-Step Calculator. After you expose your screen, you should be able to rinse out the calculator until it hits #7. If it keeps rinsing out after the seven mark, then the screen is under-exposed. If it stops rinsing out before the seven mark, the screen is over-exposed.
By hitting the seven mark, that means you'll be able to remove the emulsion with ease. Colin dives deep into the chemistry of emulsion and how it reacts with emulsion stripper, so watch the video to learn more about the chemical reactions.
COMMON ERRORS AND HOW TO FIX THEM
EMULSION BUILT UP ALONG EDGES
Sometimes the emulsion may build up along the edges in the screen when you coat a screen. While exposing the screen, printers test the middle of the screen, where their stencil is, to ensure that the screen has been properly exposed. Around the edges where the emulsion is thicker, the area is under-exposed. You may experience some difficulties in this area when you're reclaiming.
Solution — Apply your emulsion remover (at its full screen, do not dilute) to the screen and scrub. Let emulsion remover seep into emulsion to break the bonds for about a minute. If you have a pressure washer, you'll be able to blast off the under-exposed emulsion. If you're using a hose, you may be able to remove most of it, but still have chunks of it on the thicker areas of the screen. You'll have to repeat the process (and scrub hard) to remove the last bits of emulsion.
Proactive Solution — Coat the screen where there isn't a thick ridge of the emulsion along the edges. When you are exposing the screens, make sure the whole coated area has reached the seventh step by using a Step Wedge Calculator.
Insider Tip — The lifespan of emulsion remover is approximately a year based off the date on the label of the product. Over time, it will lose its efficiency. If your emulsion remover is under the year mark and still isn't working that well, a few factors may be in play. If you dilute the product with water, you may have put in too much water to where to loses its strength. If you use a dip tank, you may be losing some of the chemicals when you remove the screens; therefore, it'll just need a refresher. When using a dip tank, clean it about every 3-6 months to remove gunk and make it easier and better to clean your screens.
EMULSION LOCKED IN DUE TO SOLVENT CLEANER
Solution — Use a haze remover. The haze remover will soften the emulsion. Turn the screen around to wear the back of it (not the t-shirt side) is facing you. This side of the screen has a thinner layer of emulsion. Use a pressure washer to wash it out.
QUESTIONS ASKED BY OTHER PRINTERS
During the live video, printers asked lots of engaging questions. In case other printers have the same question, we're sharing the questions and answers that rose during the video.
What's the best way to avoid creating the ridges of emulsion on the screen?
Finish coating emulsion by a scrape of the emulsion coater. Or, you could tilt the screen closer to holding it straight up. You want the emulsion to no longer be flowing out of the coating trough.
How far away should I pressure wash?
For screen spray out, stay 12 inches away. During reclaiming, you can be very close. The concern is primarily mesh that has already been damaged.
How much psi is on your pressure washer?
The one I (Colin) used is 1700 psi, but I have used 1200 psi in most shops.
PRODUCTS COLIN USED AND MENTIONED IN VIDEO
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