Coating Glass Plates

Discussion in 'Silver Gelatin Based Emulsion Making & Coating' started by wildbillbugman, Oct 18, 2011.

  1. wildbillbugman

    wildbillbugman Member

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    Hello to All,
    Those of you who have read my posts on this Forum know that I have a pair of hands that are just not connected to my Brain. On top of that, all of my glass plate coating must be done in total darkness, with only a relatively cheap IR monocal. I have tryed the traditional pouring of emulsion; glass rod draw downs;and steel Meyer Rod draw downs. All these methods have given me problems, both with the quality of th coating and with making a big mess, as well as wasting good emulsion on the floor.
    Last night I tried,sucsesfully, the method that Denise Ross uses. She has described it in detail somewhere on this forum or on her website www.thelightfarm.com. Basicly, A catheter syringe is used to slowly lay down a coating on a glass plate nestled closely in a glass frame, slightly higher than the glass plate itself.
    This method is the easiest, cleanest method that I have ever tried. I highly recommend it.
    If I can do it, anyone can!
    Cheers,
    Bill
     
  2. Andrew O'Neill

    Andrew O'Neill Subscriber

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    Bill,

    Can I get a decent film density range for carbon transfer printing from home-made emulsion? Also, I don't want to use glass plates. Do you know
    how well does polyester sheets take emulsion?
     
  3. wildbillbugman

    wildbillbugman Member

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    Hi Andrew,
    I am certain that you can get negatives with sufficiant D-max for carbon printing. My most recent emulsions are as black as my sense of humor. As for printing on polyester,IDK. I have no interest. Denise Ross has published on this forum about her sucessful coating on untreated Melanex.
    Bill
     
  4. Andrew O'Neill

    Andrew O'Neill Subscriber

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  5. holmburgers

    holmburgers Member

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    Andrew, at the GEH emulsion workshop I coated some AZO emulsion on photoformulary's subbed Estar Melinex and it worked great. I haven't shot or developed it yet, but this is a very easy product to work with.

    You might also consider trying Dura-Lar's "prepared" (gel-coated) surface. Might also be called "wet media"??
     
  6. Andrew O'Neill

    Andrew O'Neill Subscriber

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  7. studiocarter

    studiocarter Member

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    That sounds like a great subject for a You Tube video. What size of a plate did you coat?
    Michael
     
  8. wildbillbugman

    wildbillbugman Member

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    Michael,
    All of my plates ar 5x7. That is the size I will be using should I ever get around to making art with these emulsions.,
    Bill
     
  9. Photo Engineer

    Photo Engineer Subscriber

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    I have a prototype glass plate coater that you guys should try sometime. I have coated about 4 plates at one time using it.

    Results are quite good.

    PE
     
  10. wildbillbugman

    wildbillbugman Member

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    PE,
    By "you guys" to whom are you reffering? I would be happy to try it. But Buffalo,NY, or wherever you are, is a long way from S.B.,CA ! Is this the same coater that your machinist was having trouble with the base bending? I remember, at your workshop 4 years ago, you were explaning the problem . I never heared anything else about it. It was a big chunk of high quality stainless steel.
    Bill
     
  11. Photo Engineer

    Photo Engineer Subscriber

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    Bill;

    The problem was solved shortly after that workshop and the blades were reworked to meet the 1 mil specification. Sorry, I thought I had posted that. The film and plate coaters did not have the problem due to size. I showed one prototype of each (film and plate) coater at the workshop you attended.

    Film and plate coaters are identical except for 2 things. The plate coaters are narrower in order to fit one plate, but the film coaters are 1/4" over width to allow for sheet film widths plus selvedge. And, the plate coaters allow the doctor blade to sit as high as the thickness of the plate + the desired undercut. So, a film coater will allow 2 mil - 20 mil undercut but a plate coater will allow that plus the thickness of a glass plate.

    I coat 3 - 4 4x5 plates at one time using a plate coater. I've shown the coater and the results here and I believe in the video on APUG.

    PE
     
  12. wildbillbugman

    wildbillbugman Member

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    Hi PE,
    Sorry that I lost track of your efforts with coating blades. Do you have any for sale right now? Or is this a future thing?
    As you know, my emulsions are based on modified PVA, not gelatin, and the rheology is very diffrent. You might be surprised at just how different. But I would like to get my hands on one of your gizzmos soon.
    Bill
     
  13. Photo Engineer

    Photo Engineer Subscriber

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    Bill;

    I have one prototype plate coater and two prototype film coaters. I don't have current plans for selling them. That may change, but the cost is too high for a one off item.

    As for coating PVA, BTDT as well as PVP and PVAA and co-polymers of these with other monomers. It was rather common at EK to do this in research. That is why I started a thread on testing new vehicles.

    PE
     
  14. wildbillbugman

    wildbillbugman Member

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    How we gonna try it if nobody gonna make it? :sad: I never took Metal Shop in High School. Just Print Shop, where we actualy did Type Setting and everybody got lead poisoning.:pouty:
     
  15. wildbillbugman

    wildbillbugman Member

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    PE,
    All joking aside! Could not one follow the exact same designes of your coating devices , but make them in plastic or glass? Material cost would be much lower, at least. You could break up the overall shape into simple shapes,have them fabricated, then cement them together. True, this would not be as precise as your machined stainless. But do we realy need that degree of precision? I ain't trying to " beat a dead hoarse". But,after all, you brought it up again.
    Bill
     
  16. Photo Engineer

    Photo Engineer Subscriber

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    Ok, here are some things to consider.....

    A prototype is an item being tested for suitability and if it fails is rejected, or redesigned. So, that is where I am right now. I have 2 or 3 designs under consideration.

    As for plastic or other? Well, it is SS to effect heat retention, weight stability and abrasion resistance ( for paper units mainly ) and so is still being tested in the face of other designs. Be patient.

    PE
     
  17. holmburgers

    holmburgers Member

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  18. wildbillbugman

    wildbillbugman Member

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    Holmburgers,
    I have not tried these notch type bars. Only meyer rods. I think its worth a try.
    Bill
     
  19. Photo Engineer

    Photo Engineer Subscriber

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    As I indicated before, these are common in the paint industry. I have some like those shown in the reference, but the ones I found commercially were made of aluminum, some teflon coated, and ran about $1200 for a 4" blade. Please note the sizes and undercuts in the references and try to get more detail.

    PE
     
  20. holmburgers

    holmburgers Member

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  21. Photo Engineer

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    Chris;

    They are fine provided: you avoid Copper, Zinc, Mild Steel or Iron, Galvanized, or Aluminum. Teflon over the previous is OK but if you get it scratched, you are out of luck.

    Also, they are fine provided the give a gap of 5 - 10 mils and widths that are overwidth for the film or paper you are coating by at least 1/8" on both sides. So, a 4" "blade" won't cut it, you need 4.25" to make a good 4x5 sheet of film. The 4" coater can coat a good 4" plate though with proper setup.

    PE