Sanding grey paint on a red panel

Have you ever had adhesion problems between your substrate and primer? If you have, chances are you have tried a more aggressive sandpaper grit to create a rough surface.

 

A common misconception is the deeper the sandpaper scratch the better the paint will adhere. Unfortunately, if you tried a more aggressive grit, that could actually make the adhesion worse. The depth of the scratches is less important than the frequency of scratches. 50 grit has fewer abrasive particles on the sandpaper than 320 grit. The 50 grit provides fewer, deep scratches, while the 320 grit provides more shallow scratches.

 

That increased frequency proves to be vital to the coating adhering to the surface as it levels and cures. Instead of focusing on the depth of the scratches, try to evenly prepare the substrate with 220-320 grit sandpaper and clean the surface prior to painting. For most applications this will give you the best chance to be successful.

- See more at: http://www.sherwin-automotive.com/fleet-refinishing/media-center/blog/SWAF-ART-SANDPAPER-GRIT-BLOG.html#sthash.ARSFTNdP.dpuf

Have you ever had adhesion problems between your substrate and primer? If you have, chances are you have tried a more aggressive sandpaper grit to create a rough surface.

 

A common misconception is the deeper the sandpaper scratch the better the paint will adhere. Unfortunately, if you tried a more aggressive grit, that could actually make the adhesion worse. The depth of the scratches is less important than the frequency of scratches. 50 grit has fewer abrasive particles on the sandpaper than 320 grit. The 50 grit provides fewer, deep scratches, while the 320 grit provides more shallow scratches.

 

That increased frequency proves to be vital to the coating adhering to the surface as it levels and cures. Instead of focusing on the depth of the scratches, try to evenly prepare the substrate with 220-320 grit sandpaper and clean the surface prior to painting. For most applications this will give you the best chance to be successful.

- See more at: http://www.sherwin-automotive.com/fleet-refinishing/media-center/blog/SWAF-ART-SANDPAPER-GRIT-BLOG.html#sthash.ARSFTNdP.dpufHave you ever had adhesion problems between your substrate and primer? If you have, chances are you have tried a more aggressive sandpaper grit to create a rough surface.
 
A common misconception is the deeper the sandpaper scratch the better the paint will adhere. Unfortunately, if you tried a more aggressive grit, that could actually make the adhesion worse. The depth of the scratches is less important than the frequency of scratches. 50 grit has fewer abrasive particles on the sandpaper than 320 grit. The 50 grit provides fewer, deep scratches, while the 320 grit provides more shallow scratches.
 
That increased frequency proves to be vital to the coating adhering to the surface as it levels and cures. Instead of focusing on the depth of the scratches, try to evenly prepare the substrate with 220-320 grit sandpaper and clean the surface prior to painting. For most applications this will give you the best chance to be successful.
Have you ever had adhesion problems between your substrate and primer? If you have, chances are you have tried a more aggressive sandpaper grit to create a rough surface.
 
A common misconception is the deeper the sandpaper scratch the better the paint will adhere. Unfortunately, if you tried a more aggressive grit, that could actually make the adhesion worse. The depth of the scratches is less important than the frequency of scratches. 50 grit has fewer abrasive particles on the sandpaper than 320 grit. The 50 grit provides fewer, deep scratches, while the 320 grit provides more shallow scratches.
 
That increased frequency proves to be vital to the coating adhering to the surface as it levels and cures. Instead of focusing on the depth of the scratches, try to evenly prepare the substrate with 220-320 grit sandpaper and clean the surface prior to painting. For most applications this will give you the best chance to be successful.
 

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