Question about bondo vs. metal: Did I miss a basic rule for years?

I gotta admit something that makes me feel like a total hack. About 6 months ago I was filling a dent on a 2010 Ford F-150 at the shop, and my boss walked over and watched me lay down a thick coat of filler. He just goes, 'You know you're supposed to feather that edge out in a thin layer before you glob it on, right?' I had been doing body work for like 4 years at that point and I always just slapped it on thick and sanded for an hour. He showed me his trick of doing 3 thin passes instead of one fat glob, and the sanding time dropped by half. I was also leaving pinholes everywhere from air getting trapped under the thick stuff. Now I'm wondering what other basic stuff I'm still doing wrong. Any of you guys ever have that moment where a simple tip from someone else made you realize you were making your own life harder for no reason?

3 comments

3 Comments

vera_lewis21mo ago

That thing about pinholes from thick coats hit home for me. I spent like two years thinking my primer was the problem and buying different brands before someone watched me work and was like "dude you're just burying air in there.

jennifer8331mo ago

Watched a guy do the same thing @vera_lewis2 a few years back. He was laying down clear coat like frosting a cake and wondering why it looked like the surface of the moon after it dried. Like you said, it's not the material it's the application. The thicker you go the more air gets trapped underneath and then it has to escape somewhere. I always tell people to do two thin coats with a good flash time in between instead of one fat one. Saves you a ton of sanding and headaches.

diana6171mo ago

Yeah the first time I tried clear coat I went way too thick and ended up with these craters that looked like the surface of the moon. Took me a whole weekend to sand it all back down and start over. Called my buddy who does bodywork for a living and he laughed at me for like five minutes straight before telling me the same thing - thin coats with flash time. I swear the stuff dries faster when you pay attention to the clock than when you just guess. You ever accidentally turned a project into a weekend-long sanding party like that?