Quote:
Originally Posted by Photo Engineer  Jim Browning has built a trough coater and a plate coater. I have used both of his coating machines and they work perfectly. In fact, I coated about 40 ft of cyanotype on paper with his trough coater. I let the paper air dry.
See the pictures and specifications on his web site.
PE |
See my site:
www.dyetransfer.org . THere is a .pdf file there which has pictures of a simple trough coater assembled in a lucite box. It has 3 rollers which are made from aluminum,turned accurately, and plated with nickel. One is for supply, and has an adjustable slip clutch, and a hand crank. The film/paper is wound on the supply roller (with the clutch loosened), down under the coating roller, and up to an outfeed roller. The slip clutch is then tightened so that the film/paper will be held tightly to the coater roller to prevent emulsion from reaching the back as you pull the film out of the box.
The film/paper makes a 90 degree turn around the outfeed roller and exits the box. You pour emulsion into the 'trough' under the coater roller via a funnel on the side of the box, and then start pulling by hand. It takes 2 people to run it, one to keep topping of the emulsion level, and one to pull the paper out of the box at a steady speed. It works suprisingly well. You can cut off long sheets and hang them up to dry, and keep on going until you either run out of emulsion, or substrate. Very simple, makes pretty good 20" wide coatings. You can get the proper Melinex 582 film from PF if you are coating film, or you can tape 20 x 24" baryta sheet together for coating paper, or better yet, get a roll 20" wide.
Possible improvements would be a debubbling system and a pump controlled by a level switch, which would allow one person to operate it. Also, you could attach a leader, and attach it to a motorized windup system. This way, you could regulate the draw speed. You would wind up the leader, and stop before winding up the emulsion coating. You would then cut the coated sheet off, and hang it up on a track overhead for drying, and then reattach the leader for the next strip. My thinking was to operate the coater inside the dryer. The coater would be on a counter long enough to hold the strip. There would be clips on pullys which would be lowered from above, and you would just hoist the film up and out of the way, and slide it over to make room for the next sheet. You could make large amounts of film quickly with this system, without haveing to dry the film prior to windup, as the strips would dry in the space above the coating counter, and would be out of the way.
Regards - Jim Browning
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