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Re: Plate & Roller Cleaning . . . and Ink

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  • Eric
    ... I was also forgetting the liquid photopolymer used in rubber stamps, washed in water/detergent, and using water based stamp inks. ... For amusement I have
    Message 1 of 12 , Nov 13, 2010
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      --- In PPLetterpress@yahoogroups.com, Gerald Lange <Bieler@...> wrote:
      >
      > Not quite the right assumption. Not an either or situation with
      > flexographic plates. There are water wash out flexo plates.>

      I was also forgetting the liquid photopolymer used in rubber stamps, washed in water/detergent, and using water based stamp inks.

      > Photopolymer plates, because of the post-exposure, are somewhat
      > resilient to water. Technically speaking, they are non-soluble because
      > of the molecular change imparted by the UV. I usually print damp and
      > that has never posed a problem. I've put a fully processed Toyobo
      > Printight plate in a bowl of water and after a few days only saw an
      > eruption in spots coming through the floor of the base from the adhesive
      > layer (between floor and backing).

      For amusement I have taken reject plates and soaked off all the letters. And it is indeed the adhesive layer that goes, but there can also be degredation to the image. Maybe that's just from the stresses of delaminating.
      --Eric Holub, SF
    • Kim Vanderheiden
      I think it s both amusing and admirable that each of you has thrown an old plate in water long term just to see what it did. I had thought it would dissolve,
      Message 2 of 12 , Nov 14, 2010
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        I think it's both amusing and admirable that each of you has thrown an
        old plate in water long term just to see what it did. I had thought it
        would dissolve, because of my experiences with Solarplate materiel,
        which is just another type of photopolymer plate designed for intaglio
        instead of relief. I have seen water droplets hit those plates after
        post exposure and cause deterioration without even having very
        prolonged contact. That was an earlier formula of Solarplate, not the
        current one.

        Is water insolubility after post exposure really across the board on
        all letterpress photopolymer plates, or only certain brands? Now that
        I've heard that at least some forms of photopolymer do not remain
        water soluble, I shall have to experiment with mine. I switched
        recently to Nyloprint. It would also be interesting to test the
        current Solarplate formula.

        Inquiring minds want to know!

        Kim Vanderheiden
      • Peter Fraterdeus
        I recently soaked some plastic-backed plates (bough unexposed from BoxCar in 2008) which had curled badly, on the theory that if the shrinking of the polymer
        Message 3 of 12 , Nov 14, 2010
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          I recently soaked some plastic-backed plates (bough unexposed from BoxCar in 2008) which had curled badly, on the theory that if the shrinking of the polymer which causes curling is from gradual continued drying over a year or more, then re-wetting should help relax the curl.

          In fact it did so very nicely. I left the plates, (originally processed in 2008, iirc) covered in water overnight.

          They didn't flatten completely, but relaxed back to a very manageable curl.
          I put them in the Interflex dryer for a few minutes, and they looked fine.

          Last night (about a week or so later) I got 'em stuck down on the base very nicely, and printed without any problem at all.

          P


          On 14 Nov 2010, at 10:48 AM, Kim Vanderheiden wrote:

          > I think it's both amusing and admirable that each of you has thrown an
          > old plate in water long term just to see what it did. I had thought it
          > would dissolve, because of my experiences with Solarplate materiel,
          > which is just another type of photopolymer plate designed for intaglio
          > instead of relief. I have seen water droplets hit those plates after
          > post exposure and cause deterioration without even having very
          > prolonged contact. That was an earlier formula of Solarplate, not the
          > current one.
          >
          > Is water insolubility after post exposure really across the board on
          > all letterpress photopolymer plates, or only certain brands? Now that
          > I've heard that at least some forms of photopolymer do not remain
          > water soluble, I shall have to experiment with mine. I switched
          > recently to Nyloprint. It would also be interesting to test the
          > current Solarplate formula.
          >
          > Inquiring minds want to know!
          >
          > Kim Vanderheiden
          >
          >
          >
          >
          >
          >
          >
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