Dude, if I showed you how much Bondo I use, you would laugh. None. I use tiny blobs of spot putty in tiny amounts at a time to get rid of 3D print lines and seams. It takes sooooo looong to wipe those seams from existence. I'm going for the "cast-worthy" approach, so i'm trying to get it as close to perfect as possible, which results in a lot of sanding on something so tiny. Lots of intricate sanding.