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Re: reporting back: vinager and water on polymer plates

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  • greenberry
    gerald, thanks again for an in depth response, now, as for the printer s alcohol, the little that i remember (it means really little ) from a chem class from
    Message 1 of 7 , Nov 1, 2003
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      gerald, thanks again for an in depth response,

      now, as for the printer's alcohol, the little that i remember (it means "really little")
      from a chem class from years back, alcohol won't stay 1% water as soon as it's
      exposed to moisture??? ie, is there a special way to keep it away from moisture while
      maintaining the convenience and ease of its application? or would it make no
      noticeable difference with respect to the polymers (with a greater concentration of
      water in the solution)?

      one nice local letterpress man has told us recently in his elaborate multi hour lectures
      that there are two types of photo polymer plates, one that is washed by water and the
      other by alcohol. i've always knew of the water version. is alcohol version still
      susceptible to degradation by water like the water washed ones?

      thanks,

      hiroshi

      --- In PPLetterpress@yahoogroups.com, "Gerald Lange" <bieler@w...> wrote:
      > hiroshi
      >
      > Any "quick drying" solvent, formulated as a plate wash or type wash,or
      > even similar materials, such as pure printer's alcohol (1% water),
      > will work. After I wipe plates, I immediately spray them with
      > compressed air to additionally dry them out and get rid of any
      > particulate matter (from the rag and accumulated paper lint).
      >
      > Press washes, and other slow drying solvents, should not be used to
      > wipe "printing surfaces" (plates or type) as they leave an oily
      > residue that will interfere with subsequent ink laydown.
      >
      > Most sheet photopolymer intended for letterpress is water-soluable.
      > Don't know how useful experiments with soaking plates in liguids are.
      > With any kind of solvent that contains water, you will probably see
      > some kind of disintegration of the material.
      >
      > Gerald
      >
      >
      > > a while back i asked about the compatibilities of blanket wash and
      > polymer plates
      > > we use - as my understanding was the polymers we use were water
      > washed (as
      > > opposed to alcohol?) and the wash was "aqueous" naphtha. the was was
      > > recommended to us by other letterpress shop and a reputable local
      > (and nationwide?)
      > > ink supplier. of the replies, no one objected, i believe. any how,
      > i accidently left the
      > > wash on one polymer one overnight and it ate away. (oops.)... but
      > what about the
      > > effect of them on daily cleanup?
      > >
      > > with respect to vinegar vs water on how they would breakdown the
      > polymer, from a
      > > little dunking experiment yesterday, the results were about the same
      > in the period of
      > > about 20 min or so - with respect to how they would crumble with
      > pressure. so it
      > > looks like it's the water, not the acetic acid that's affecting?
      > >
      > > will a second (and multiple) dried polymer regain its original specs?
      > >
      > > thanks again for help,
      > >
      > > hiroshi
      > >
      > >
      > >
      > > [vinegar, vegetable oil, water, photo polymer plate, blanket wash,
      > water based, how to
      > > clean]
    • Gerald Lange
      hiroshi Don t know about the hydration. I buy IPA 99 (99% Pure Isopropyl Alcohol) made by Hurst Graphics, distributed in LA by KellyPaper, among others. I only
      Message 2 of 7 , Nov 2, 2003
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        hiroshi

        Don't know about the hydration. I buy IPA 99 (99% Pure Isopropyl
        Alcohol) made by Hurst Graphics, distributed in LA by KellyPaper,
        among others. I only use it for post-printing purposes though. Don't
        actually use it for cleaning plates. KellyPaper also sells Alcohol
        Substitute (ingredients: 100% water) for about $10 a gallon. :-)

        At any rate, if the alcohol is in a solvent can, I suspect it will not
        draw as much water as your chem class might have indicated.

        Your nice local letterpress man is correct about the two different
        kinds of photopolymer. Most sheet photopolymer (as used in letterpress
        purposes) is water-washout. But more and more, even flexographic sheet
        photopolymer is water-washout. I can process flexographic plates
        (water-washout) in my processor simply by increasing the bath
        temperature and using water from a soft water conditioner. More of a
        market there than there is for letterpress!!! Liguid photopolymer
        and/or solvent-washout photopolymer are slowly becoming a thing of the
        past.

        Gerald


        > gerald, thanks again for an in depth response,
        >
        > now, as for the printer's alcohol, the little that i remember (it
        means "really little")
        > from a chem class from years back, alcohol won't stay 1% water as
        soon as it's
        > exposed to moisture??? ie, is there a special way to keep it away
        from moisture while
        > maintaining the convenience and ease of its application? or would it
        make no
        > noticeable difference with respect to the polymers (with a greater
        concentration of
        > water in the solution)?
        >
        > one nice local letterpress man has told us recently in his elaborate
        multi hour lectures
        > that there are two types of photo polymer plates, one that is washed
        by water and the
        > other by alcohol. i've always knew of the water version. is alcohol
        version still
        > susceptible to degradation by water like the water washed ones?
        >
        > thanks,
        >
        > hiroshi
        >
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