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Re: [PPLetterpress] Re: Ink and solvent question

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  • Timothy Trower
    I ll add a bit of clarification to my last posting. The job I am running is on hospital X-Ray jackets, 14x19 inches. The sides of these folders are printed
    Message 1 of 11 , Jan 18, 2004
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      I'll add a bit of clarification to my last posting. The job I am running is on hospital X-Ray jackets, 14x19 inches. The sides of these folders are printed first with a colour bar about an inch wide on each side of the folder, front and back. I'm as good at make-ready as the next guy, and have leveled out the unevenness of the folders (ranging from two to four thicknesses).

      The plates are, therefore, just long strips of polymer mounted on a wooden base to bring them type high. They wear along both the inside and outside, whether there were originally two, three or four layers of folder. Part of the plate will remain smooth, accepting a decent layer of ink, and the parts that wear become gummy and sticky (for want of a better technical term) hold a much thinner layer. They only cost about $30 per set for the plates (unmounted) and I certainly have this built into the cost of the job -- but changing them out two or three times on a job is a pain.

      I would be glad to send anyone a cross segment of the plate for further analysis, and simply put, have used this as a good example of why any letterpressman should never stop learning about the trade.

      Thanks again,

      Tim

      [Non-text portions of this message have been removed]
    • Gerald Lange
      Tim Photopolymer is very perceptive and will adjust to irregularities in makeready as well structural density. I d suspect here first the lack of density
      Message 2 of 11 , Jan 18, 2004
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        Tim

        Photopolymer is very "perceptive" and will "adjust" to irregularities
        in makeready as well structural density. I'd suspect here first the
        lack of density because of the use of wood for a base, as well as the
        method of application (adhesive) of the plate to the wood. On an
        extended run, irregularity will gain because of compression and that
        is probably causing your wear.

        Photopolymer performs best with an extremely hard, tight level packing
        and a very dense precision base, such as the aluminum type made by
        Boxcar, Bunting, or PaT Reagh. Any slack in the chain and you are
        asking for trouble. Spend a little dough on a proper base and I
        suspect you might solve your problem.


        Gerald


        >I'm as good at make-ready as the next guy, and have leveled out the
        unevenness of the folders (ranging from two to four thicknesses).
        >
        > The plates are, therefore, just long strips of polymer mounted on a
        wooden base to bring them type high. They wear along both the inside
        and outside, whether there were originally two, three or four layers
        of folder. Part of the plate will remain smooth, accepting a decent
        layer of ink, and the parts that wear become gummy and sticky (for
        want of a better technical term) hold a much thinner layer. . . .
        >
        > Tim
        >
        > [Non-text portions of this message have been removed]
      • John G. Henry
        In response to Tim s posting: The comment that the plates are getting gummy is a concern. This might indicate that the plates were not properly processed.
        Message 3 of 11 , Jan 19, 2004
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          In response to Tim's posting:

          The comment that the plates are getting "gummy" is a concern. This
          might indicate that the plates were not properly processed. Most of
          the polymer plate materials need to be thouroughly dried and then
          post-exposed to insure that all the polymer has been cross linked and
          hardened.

          I have had plate problems when I have tried ot rush the process and
          not allow adequate drying time.

          The polymer plates should last for many, many thousands of
          impressions
          without a problem.

          If the plates have no specific image and are just for printing color
          bars, you could easily go to a sheet metal fabricator and have them
          shear down some brass or copper to the size strip you need from
          appropriate caliper material. This would provide a "permanent" plate
          for your application.

          John Henry

          --- In PPLetterpress@yahoogroups.com, "Timothy Trower"
          <tjtrower@s...> wrote:
          > The plates are, therefore, just long strips of polymer mounted on a
          wooden base to bring them type high. They wear along both the inside
          and outside, whether there were originally two, three or four layers
          of folder. Part of the plate will remain smooth, accepting a decent
          layer of ink, and the parts that wear become gummy and sticky (for
          want of a better technical term) hold a much thinner layer. They
          only cost about $30 per set for the plates (unmounted) and I
          certainly have this built into the cost of the job -- but changing
          them out two or three times on a job is a pain.
          >
        • E Roustom
          ... Ink and solvents won t do a thing to your plates (water will). On these long runs, use little impression as you can get away with. I don t know that a hard
          Message 4 of 11 , Jan 19, 2004
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            > I now have an application
            > that requires 20000 impressions per run, and do not want to have to replace
            > the plates every 5000 to 10000 impressions.
            >
            Ink and solvents won't do a thing to your plates (water will). On these long
            runs, use little impression as you can get away with. I don't know that a
            hard plate is best for what you're doing, but what I can tell you is that
            with a hard plate I just ran 34M sheets using too much impression (by any
            standard, but the client is always right) and while around 25M impressions I
            started to notice some deterioration (rounding of the edges), I did not have
            to change plates, I did have to adjust my rollers slightly. The small sans
            survived with no adjustments the whole run through. With my roller
            adjustments the large serif looked as good at the end as it did in the
            beginning.
            Gerald's suggestion that you move to hard base is a good one. I've used
            milled PVC with sucess. Much cheaper than aluminum. The trick is to find a
            machine shop that will mill it properly.

            Good luck,

            Elias
          • Timothy Trower
            Given that my local engraver may be a fault, is there another engraver in the Missouri area making polymer plates? I currently use Phillips Engraving here in
            Message 5 of 11 , Jan 19, 2004
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              Given that my local engraver may be a fault, is there another engraver in the Missouri area making polymer plates? I currently use Phillips Engraving here in Springfield, but I do have concerns about their dedication to quality since the death of the owner a few years ago. Their explanation has been that my inks are at fault -- but this is a relatively isolated problem.

              I will try a solid base, but due to the need to mold to the differing thicknesses, a solid brass or copper bar wouldn't be the answer. A regular magnesium engraving would work -- kind of -- but would be beaten down rather quickly.

              I really do appreciate the help and ideas that I am getting. It will be another three or four months until this job repeats itself, but I want to be ready for it.

              Tim
              ----- Original Message -----
              From: John G. Henry
              To: PPLetterpress@yahoogroups.com
              Sent: Monday, January 19, 2004 8:42 AM
              Subject: [PPLetterpress] Re: Ink and solvent question


              In response to Tim's posting:

              The comment that the plates are getting "gummy" is a concern. This
              might indicate that the plates were not properly processed. Most of
              the polymer plate materials need to be thouroughly dried and then
              post-exposed to insure that all the polymer has been cross linked and
              hardened.

              I have had plate problems when I have tried ot rush the process and
              not allow adequate drying time.

              The polymer plates should last for many, many thousands of
              impressions
              without a problem.

              If the plates have no specific image and are just for printing color
              bars, you could easily go to a sheet metal fabricator and have them
              shear down some brass or copper to the size strip you need from
              appropriate caliper material. This would provide a "permanent" plate
              for your application.

              John Henry

              --- In PPLetterpress@yahoogroups.com, "Timothy Trower"
              <tjtrower@s...> wrote:
              > The plates are, therefore, just long strips of polymer mounted on a
              wooden base to bring them type high. They wear along both the inside
              and outside, whether there were originally two, three or four layers
              of folder. Part of the plate will remain smooth, accepting a decent
              layer of ink, and the parts that wear become gummy and sticky (for
              want of a better technical term) hold a much thinner layer. They
              only cost about $30 per set for the plates (unmounted) and I
              certainly have this built into the cost of the job -- but changing
              them out two or three times on a job is a pain.
              >





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            • E Roustom
              ... Do you mean like an envelope (seams, flaps, etc.)? As long as your packing includes all the makeready, it should not matter what hardness (brass, polymer)
              Message 6 of 11 , Jan 20, 2004
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                > but due to the need to mold to the differing thicknesses
                Do you mean like an envelope (seams, flaps, etc.)?
                As long as your packing includes all the makeready, it should not matter
                what hardness (brass, polymer) your matrix is.

                If I were you... I'd get one of those plate manufacturers to supply to
                whoever makes your plates a sample of the softer polymers. I tried them once
                on halftones - cut makeready time in half. I'd almost bet this job would
                work best with a softer plate.

                >but I do have concerns about their dedication to quality
                Between NA Graphics and Box Car you can't go wrong on quality, attention to
                detail and ability to make custom changes.

                E.
              • arizonaprinter@yahoo.com
                WE have on several jobs used offset blankets (Hard Dot) as a backer and it will conform to the envelope and eliminates the smashing of a die. I would not
                Message 7 of 11 , Jan 20, 2004
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                  WE have on several jobs used offset blankets (Hard Dot) as a backer and it
                  will conform to the envelope and eliminates the smashing of a die. I would
                  not recommend a mag die as they are to soft and will smash out. I print on
                  a lot of catalog envelopes this way. I also have an offset shop so blankets
                  are free to me. just got down to a printer you know and ask them if they
                  have any old blankets you could buy or have. (They are also good for
                  placing tools on in a tool chest.

                  From: E Roustom <ERoustom@...>
                  Reply-To: PPLetterpress@yahoogroups.com
                  Date: Tue, 20 Jan 2004 14:40:36 -0500
                  To: <PPLetterpress@yahoogroups.com>
                  Subject: Re: [PPLetterpress] Re: Ink and solvent question



                  > but due to the need to mold to the differing thicknesses
                  Do you mean like an envelope (seams, flaps, etc.)?
                  As long as your packing includes all the makeready, it should not matter
                  what hardness (brass, polymer) your matrix is.

                  If I were you... I'd get one of those plate manufacturers to supply to
                  whoever makes your plates a sample of the softer polymers. I tried them once
                  on halftones - cut makeready time in half. I'd almost bet this job would
                  work best with a softer plate.

                  >but I do have concerns about their dedication to quality
                  Between NA Graphics and Box Car you can't go wrong on quality, attention to
                  detail and ability to make custom changes.

                  E.



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                • Timothy Trower
                  just go down to a printer you know and ask them Hadn t thought of that -- and, as a trade printer, my only customers are printers! so I ought to be able to
                  Message 8 of 11 , Jan 20, 2004
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                    "just go down to a printer you know and ask them"

                    Hadn't thought of that -- and, as a trade printer, my only customers are printers! so I ought to be able to find something to try.

                    Tim

                    [Non-text portions of this message have been removed]
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