I had recently purchased some Iron Armor primer at Harbor Freight just because the price was so appealing for a sandable filler primer. I just got around to doing a quick test, because I'm as curious as anyone if it's worth trying! A few points: First; it does have a VERY fine graininess, but nothing unusual for a primer with higher solids content for filling. You have to feel it, you can't see it, even in a WET coat. Second; it sprays with a good pattern, and covers very well. Third; I was unable to make it craze a model car body or even one of those cheap plastic Wal-Mart spoons, and in my experience, plastic spoons craze easily. (I sprayed 2 heavy wet coats on each, no holding back for testing purposes) Fourth; I like the smell! Seriously, it reminds me of the smell of Kylon Sandable from 10 years ago, a primer I really liked for modeling. BONUS points; the model pictured is an old glue bomb Monogram 66 Chevelle street machine I will be restoring, molded in RED, and it ain't bleeding through! Sprayed day before yesterday. The primer is a very light gray color, the handle of the (white) spoon was not sprayed at all.