Definition - What does Curtain mean?
A curtain refers to the long horizontal runs in a coating film that occur on vertical surfaces when a coating is applied too heavily. This is a defect in the coating process. Curtains make the surface look uneven and increase the probability of the inner material being exposed to outside elements, thus facilitating the corrosion process.
Corrosionpedia explains Curtain
The appearance of long horizontal runs or curtaining is a defect in the coating process. It can be rectified using a curtain coating, a process in which the object or substrate that needs to be coated is guided through a curtain of fluid.
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