Appreciation post: I finally get why my old boss made us hand-sand every primer coat

For years, I thought using a DA sander on primer was fine, especially on flat panels. Then I took a job at a shop in Spokane where the manager, Carl, insisted we block sand every single primer layer by hand with 400 grit. It felt slow and pointless. But after a black pearl tri-coat job last week, I saw zero sanding marks under the clear, something I could never say before. The extra hour of hand work saved me from a redo. How many of you still block sand primer, or have you found a faster way that works just as well?

2 comments

2 Comments

rowanc2927d ago

Wait, you really see a big difference from skipping the DA entirely? I've always used a DA for the rough leveling, then hand block the final coat. @willow_king has a point about the last pass being key. Maybe it's more about the final step than doing every single layer by hand. That seems like overkill on a simple repair.

willow_king27d ago

Okay, so you saw zero sanding marks under the clear. That's the real proof. But when you say "block sand every single primer layer," do you mean you're doing it after every guide coat, even on the second or third round of primer? I'm trying to figure out if the magic is in that last blocking pass, or if skipping the DA for the initial leveling is what actually makes the difference.