Why does eurthane spray good sometimes and sometimes not.?

Question

I work on antiques and sometimes polyeurthane sprays good but sometimes i get Orange peal .

Answer 1

Orange peel is caused by the finish not flowing out, or the spray is not heavy enough.  Polyurethane should be well-shaken in the aerosol can, and be at room temperature.  The spray should be heavy enough to completely coat the surface.  You should be spraying close to the surface--6" or so, depending on the spray pattern.  It is also a good idea to prep the surface by sanding it, and using a dewaxer like VM&P naphtha (available at the hardware store) to remove surface contaminants.  Be aware that not all finishes are compatible with each other, so putting lacquer over PU, for example, will lift your PU layer.  PU may also flake off of lacquer.  Best to stick with the same type finish.