Pin-Holing or Bubbling
When tiny holes are produced on the finished surface, often arising from the substrate, the defect is called Pin-holing or Bubbling.
|Atomized water in the air||Clean the air separator and drain water from the line|
|Fine drops of moisture coming through the separator in the spray apparatus||Clean spraying equipment and purge the separator|
|The open pore of wood has air trapped inside||Use a thin wash coat to penetrate the pore|
|Production of fine bubbles after force drying||
• Use lengthened and recommended flash time, before drying.
• Reduce the heat in the drying room.
|Bubbling of Carbon Dioxide from polyurethane causes pin pricks to appear||
• Happens when polyurethane reacts with moisture.
• Use retarder and apply successive thinner coats.
|Drafts Causing Surface drying and forcing the solvent to break through the surface film and Evaporating to leave pin pricks||Avoid drafts, reduce viscosity or retard dry the material.|
|Trapping of air by heavily viscous paint||Thin the paint|
|Heavy film||Use thinner coats|