A long STRAIGHT flexible board (plastic or ?). You will see waves with it that you won't see without. I don't have one, but Jeff is nearly done with the body work on my 67 Barracuda. I'll have to see if I think I need one. I'd really like to get paint on this weekend.
put tape on the top edge of the line and sand,then put tape on the bottom edge and sand some more,this will keep you from sanding down the body lines.also,a light spray of dark primer will show the imperfections better,just focus on the lighter areas after sanding it down.
my preference is a long straight board.I prefer non flexible.If your not an experienced body man you can get yourself in trouble with a flexible board.It can cause waves.Either way just take your time.
I have already long boarded the sides. I have a way of seeing even what the board wont show with a guide coat. I use Omni or PPG cleaner. Wipe it on good and wet. Stand off at an angle and its like it has a good coat of clear on it. Glossy as can be! Look at the reflection and you can see even the slightest wave. That is not my issue. The lines...... I want the lines to be straight. I can see they arent perfect. They aren bad.... but I want a way to make them as near perfect as I can. I am using straight line tape above the line with a guide coat, sand, then lay down tape below it, pull the top piece and guide coat and sand. I am just wondering if there is a better way.
Run your tape the full length of the body line on top. 2 full wet coats of primer let dry and sand with a long block. Then repeat on the bottom line. That should make your line strait. Thats how I did my car. Dave