The best coating rod?

Discussion in 'Alternative Processes' started by Davec101, Apr 11, 2007.

  1. Davec101

    Davec101 Member

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    I am having a bit of trouble coating larger prints (11x14) with my existing coating rod which is a custom made 17" rod with the two ends made into handles ( \____/ ). I am looking a getting a larger 'puddle pusher' type rod made, will this be better?

    Does anyone have any tips or suggestions for any other type of rod for coating a large surface area.

    many thanks
     
  2. Loris Medici

    Loris Medici Member

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    What exactly is your problem with the current rod? I never used a rod bigger than 13" but here's what I can say:

    Your coating station must be absolutely level (control with spirit levels), your paper shouldn't become wavy when it gets wet (use sturdy / thick paper), the rod should be absolutely straight, 17" is pretty wide -> if you have to use a lot of sensitizer (> 4-5ml) then a rod with slightly bigger diameter may help.

    Regards,
    Loris.
     
  3. Davec101

    Davec101 Member

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    Thanks Loris for your input, the problem is that when i coat the watercolour paper it sometimes loses the 'bead' of sensitiser when i first draw downwards with the rod and i am left with gaps. ( hope that makes sense)
     
  4. gr82bart

    gr82bart Subscriber

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    I was told (I'm a newbie at this) that the best coating rod is a brush. That is, forget the rod and go with this Richardson (?) brush - which I still haven't been able to find locally.

    Ron (Photo Engineer) uses a rod I think, so he may have much, much better advice.

    Regards, Art.
     
  5. Loris Medici

    Loris Medici Member

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    Could be one (or a combination) of these:
    1. Non-level and/or non-flat coating surface
    2. Non-perfectly-straight coating apparatus
    3. Too little sensitizer

    Pay extreme attention to the first two list items.

    How much solution do you use? I use 0.2ml solution per 10 square inches (can fluctuate around 0.15 - 0.25 depending on paper / sensitizer).

    A good brush and a quick + light hand is also a good coating method - especially for big prints. (In this context, big is > 8x10".) See for Da Vinci brushes is Richeson's are hard to locate and/or price is prohibitive.

    Regards,
    Loris.
     
  6. Photo Engineer

    Photo Engineer Subscriber

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    Actually, I don't use a rod. If I do alternative processes, I use either a brush or one of my coating blades. I've also seen a wire wrapped rod used for coating, but it coats a lot more sensitzer due to the thickness of the wire. That can be adjusted, but only within limits.

    It sounds like you may need some surfactant in your solution. Usually a drop of photo flo or something like that will help.

    PE
     
  7. Davec101

    Davec101 Member

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    Thanks for the advice PE. How does a wire wrapped rod work?, i have seen one once in a book if i recall but not seen it in action. Also what is a coating blade?, I have yet to see one of those.
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    Dave;

    The wire wrapped rod is elevated above the surface of the paper, and the sensitizer puddle is pushed ahead of the rod by rolling the rod on the suspending wire wrapping. It leaves behind a layer of sensitizer as thick as the rod. The guage of the wire determines the thickness of the puddle.

    The coating blade is described in posted pictures and the video in the Making and Coating forum here.

    PE