Originally posted by Truck'26:
All you guys taught me is to mix in steel grit into the first layer of Bondo 
That's why you want to use a weak magnet. A vinyl advertising type magnet barely has enough juice to stick to metal with a coat of paint. While I've admitedly never tried mixing filler with metal shavings then sticking a magnet to it I doubt that weak of a magnet would stick. I've been wrong once or twice in my life
and could be wrong here but I doubt it. If someone tries it let us know what happens. If I have to eat some crow I'll bring the salt shaker.
