Crisp, straight body lines

[CARS]

I was at a car show this last weekend showing off one of my customers cars and 95% of the comments were about how straight and crisp the body lines were. As anyone who has repaired a vehicle with a million door dings or installed a cheap, aftermarket panel on a vehicle knows how hard it is to have good looking lines. It seems that after all the welding, filler work, primer, base coat, clear coat and wet sanding/buffing the body lines loose their shape or worse yet on a subtle line, totally disappear.
Here is a trick I use to keep them sharp or should I say actually make them sharper so that after all the blocking, painting, blocking, and buffing is done they are still there.
Yes, I know everyone hates filler but you know what, when used properly it is very strong and easy to get to do what you want it to do. (my English teacher is rolling in her grave because of that sentence )
First photo shows me laying out some masking tape on the edge of the line. From there I will apply some body filler up against the tape. The tape thickness is what dictates how thick the filler goes on. If I need a more pronounced line I will lay a few strips of tape on one another.
The second pic shows the filler applied. If you still can't get over the use of filler take a close look. You will see numerous places where I have sanded through. I doubt that there is more than 3/16" deep anywhere. Before the filler dries remove the tape and let the filler cure. Sand it with the longest, straightest sanding block you have and don't, I repeat don't roll the block over the edge or you have just defeated the purpose.
Once you have that all sanded do the opposite side of the edge.
Pic 3 shows the filler applied and the tape removed. I found some white hardener (ya, who was the rocket scientist who thought no one wanted to see if the filler was mixed or not) to try and show the straightness of the line using this technique.
I think you will get the idea. Just remember to never sand OVER the edge of the body line or it is now a rounded edge. If you don't need a line that crisp the same tape idea works with primer. Lay the tape on the top of the body line's edge, mask with paper on the top side to stop any overspray and give it a couple of coats. (be sure to follow your paint mfg's instructions, bla bla, bla...) After the last coat, remove the paper and tape and give the whole panel (or vehicle) a few more coats. The "shelf" you have created by taping on the top side of the edge will be filled in and you will have a ever so slight line where your body line is. Sand as you should (remember, don't go over the edge) and you should be left with a crisp line.
This sharp line will be rounded off to a natural looking line once you apply a coat of sealer, 4 coats of base coat, and 4 coats of clear so don't think we are trying to get a line that will cut small children when they touch your car. (Although that would stop them from doing that wouldn't it... )
Class is open for discussion if anyone has any questions...

[Nick C]

Great trick CARS!!!! Thanks for sharing this.

[Metal Finisher]

I have been using this method for years. Just the other day I used it to get the line straight on Mustang with a damaged front fender, a new ( aftermarket) door and a replacement rear 1/4 panel (both sides). I put down a single peice of tape along the bottom line from the front fender to the rear quarter. And then skimmed the whole side of the car removed the tape and sanded it. Then I put tape on the top of the line and skimmed the part below the line and sanded it. Result a perfectly straight side and crisp line. When I did this I filled the gap between the door and the 1/4 panel, fender and rocker. And left it that way untill I was done sanding and then I took a dye grinder and cut it free, and then sanded the edges to there proper shape. Invisible repair.

[goodfellow]

Excellent post -- that is true craftsmanship.

[Ultra Al]

Great tip Cars, and to think of all the precautions usually taken to HIDE a tape edge on graphics. AL

[ss-truck]

Cars , thanks for bringing that point up. Body detail lines are very important in accomplishing great body work . I have seen far too many times where the body lines are lost or crooked . Its a lot of work to get all that right but well worth it in the finished product.