marketing is the difference, all 'light weight' fillers are pretty much the same, the variation might be in how easy they sand and how well the sandpaper holds up - they likely say one or the other will 'pinhole' less, but that's more technique than product .... can't imagine why someone not big on fillers would buy 3 gallons tho', I didn't use much over a quart on daBus
and if there's any chance your catalyst has been subject to freezing temps, get some fresh
Bill
