Here is a video of spreading body filler. There are a few things to notice in it.
- The first, is that I am spreading the filler over 80 grit. I am very strict about this, every 40 grit scratch gets sanded out.
- The first pass is very thin, and pressed in very good. This is to make sure filler is squeezed into any scratch or pin hole, and it allows the filler to adhere better. Otherwise the body filler is more just laying on the surface.
- The second pass is where the filler is actually added.
- I make several passes to get as many air pockets squeegeed out of the filler as possible. The more you can spread it the better to work everything out of it. Try not to just spread the filler on and leave it after one pass with the spreader.
- Notice the angle of the spreader. It is pretty flat with the panel. The less perpendicular with the panel it is the better.