Kreene, a flexible and matte transparent plastic, is used in a platemaker’s vacuum frame to hold films securely against photopolymer plates during exposure. But over time, it’s the nature of kreene to get wrinkled and lose flexibility. When you find that your kreene no longer creates a smooth seal, it’s time for a kreene replacement! At Boxcar Press, we replace our kreene every few days, but we process a lot of plates. With lower use, kreene can last for several months.
To replace your kreene: cut out a square of kreene to the size of the previous kreene piece (your kreene will be slightly larger than the grooves in the vacuum table). If your platemaker has one, pull the round bar out the previous sheet of kreene. Affix the new sheet of kreene to the bar with double-stick tape. Lay the kreene in position on the vacuum table and turn the vacuum on. Work out any wrinkles in the kreene so it remains flat. Using double-stick tape, affix the kreene edge opposite the bar to the vacuum table. You can then roll the kreene out over your vacuum table and start exposing your polymer plates. To increase the life of your Kreene, roll it out flat in your platemaker at the end of the day.
A platemaker’s brushes wear out after prolonged use: these brushes should be replaced every 6-36 months. You can tell when a brush is tired out because the bristles are matted down. You can lengthen your brush life by keeping the brushes wet all the time and running your fingers through them to encourage the bristles to stand up. We sell replacement brushes for all of our platemakers: please e-mail or call us to order these.
Magnetic mounting rubber and rigid mounting rubber come pre-sealed. Over time, this seal breaks down. You can make touch-up repairs with our green die sealer. Remove any old die sealer and apply green die sealer in a thin bead to the edge of the mounting rubber. Let dry overnight.
Drain the platemaker often, usually after every 10 to 12 processed plates. To drain, open the drain valve. The washout water is safe to go down the drain. To refill, close the drain and fill with water. Leave the tank full of water so the brushes don’t dry out. If you’re leaving the machine unused for an extended period of time, add half a cup of bleach to the water to resist algae. When you use the machine again, drain and refill the tank with fresh water.