Poor metal work, bad filler work. Too much sanding pressure causing some of the lower crown panels to flex. Dull worn paper/ wrong grit lends itself to using heavy pressure. There are other reasons, you want to avoid them all.What other actions could cause a "wave" (s) on a finished panel?
I'm fairly new to this too only having done two restorations. I have been fairly pleased with what I have done so far but always look to improve. Barry, if color sanding a door like you mentioned would the preferred direction be front to back or top to bottom? Just depends on what the shape of the panel is? Reason I ask is I recently did an early bronco and I know I had it blocked straight but I'm not totally satisfied with the tops of the quarters. The upper part of the panel is say 5' long but only 8" tall and I sanded vertically. There is a little wave I may have caused since I sanded the short direction.
Funny that I came across this thread. I am actually in the process of color sanding a 72 cuda. I am normally a collision guy so all of my jobs are pretty much just nib sanding. This is actually my first job requiring this much detail. Yesterday I was going to start color sanding the roof with a block and was hesitant on which direction to go, because the roof is almost perfectly square. Which direction would you think in a situation like this?I like to travel the longest length of the panel. Example, for a door you would go front to back rather than top to bottom. Same with a hood or roof or quarter. Just go back and forth, trying to sand each panel as evenly as you can. Never stay in one area trying to remove a defect. Keep sanding the entire panel until the defect is removed.