Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Dennis, the two part auto body repair material you call BOG is called Bondo here in the US.  I have used it a number of times to repair rust and dents on older cars.  It works virtually the same as JB Weld, just sold in larger containers.  It will work fine for your purposes so long as all oil and loose residue is removed first.  The stuff files easily, so maybe you just glop some on the magnets and the recess around them, then file like a sculptor.

Look forward to the finished product.

Rog