When to prime twice

Ideally, every project would get polyester primed once.  In reality that doesn’t always happen.  Some tips to help get the body work to a point for one prime include:

  • Using the right blocks, True Blox. That’s not a pitch, it’s the idea that these blocks get the body work as close as possible to the correct shapes. If the body work is shaped correctly, when the primer is blocked down, there is very little being corrected.   
  • Check your body work. Using aluminum flat stock or c-channel to check the panels will help show you how straight the body work actually is.  Here is a link to more on that. https://www.trueblox.com/blogs/body-filler/how-to-know-if-your-body-work-is-straight
  • Finish the body filler in 150 grit.  This helps refine the body work even further, and is a much smaller scratch for the primer to have to fill, leaving you more material to sand. 

If you need to prime twice, here are a few things to keep in mind. 

  • There should be quite a bit of filler or metal showing through the primer. 
  • You should be completely out of material to sand. This keeps the material build as low as possible. 
  • Sand corners out as much as possible, especially inside corners.  Polyester primer can build a lot, and you don’t want  that much material stacked up in corners.  You work will also look a lot crisper if all this is sanded down. 
  • If there are only a couple break throughs to filler after 220 grit, you might want to consider spot priming those areas. 

Leave a comment