I've started on my 250 gal build and came across some rust pitting on the outside of the tank. I'm really wanting to make this look nice when I'm done so I'd like to fill the pitting with something. Would be too large of an area to weld/grind. Does anyone know of a product that can be applied over the pitted area then sanded/ground prior to painting? It's on the CC around the doors area (have yet to cut them) and would be very noticeable if not filled. Thanks.