I coated one sheet which I coronized only for the lower half. This should allow me to compare with the same coating.
In addition, I have coated about 3-4 or more these very same A4 PET sheets before, with same emulsion and same coating blade, and every time the emulsion has started to loosen at least at the edges, after 2-5 minutes of processing. If this seems to stick, I'll process longer and longer. If it survives a longer-than-normal process with vigorous agitation then it's probably okay. That will be my test.
If it doesn't work, then I'll try to rise the voltage. The current design can give at least 8 kV. It's possible to do but the risk of arcing will become higher.
My coatings still need to improve, though. Our last emulsion (the one that fogged, good for practicing though) is also way too dilute and thus hard to coat. (Of course I could add gelatin.)
Emulsion, thanks for list of HV sources; In fact, if this works, I think that the whole unit can be found in a photocopier or laser printer; just remove the melting unit and toner unit and you have a complete product! But that would have been too easy, I had to construct something .