Air filter top flange

Does anyone know the best way to preplace the top flange on a S3 air filter box? The original flange has broken but I want to keep the box as its an original off my SX150 (complete with innocenti part no stamping).
Is this flange soldered , welded or sweated on? is it easy enough to grind off with a dremmel?
Any advice would be appreciated, but don't say buy another complete box, I've already got one and this will be the donor flange.
Cheers to all, Mel
Is this flange soldered , welded or sweated on? is it easy enough to grind off with a dremmel?
Any advice would be appreciated, but don't say buy another complete box, I've already got one and this will be the donor flange.
Cheers to all, Mel
