Here's a dual product recommendation. If you have rust to deal with, this is a pretty good way to go.
The photo below shows two sections of the same casting,one before being treated and one after scrubbing with the Scotchbrite, vacuuming, and brushing on the Krud Kutter “The Must For Rust.”
I am only using this treatment in concave areas of the casting. The flat and convex areas I stripped to bare metal using an 80-grit flap sander on my 4-1/2” grinder. It went remarkably fast, far faster than hand sanding would have. Once the metal was bare, I wiped the whole casting down with a rag dampened with the Krud Kutter to prevent flash rusting before I could prime. I then warmed the casting with a heat gun and sprayed primer on the base. I feel good about this project now: the paint transformed my impression of where this is going. I'm also surprised at how rough Delta left the casting. There are a few obvious marks from a quick once-over with a grinding wheel, but otherwise the thing is rough as a cob. So I feel like my finished paint job might be better than the original.
I'm not sure what my pace will be as I complete this project. I need to build a base. Now I'm thinking I'll paint that too. But I'm excited to have a bandsaw in the shop again. Stay tuned for progress updates.
More details on the products: The Scotchbrite is far more aggressive than what you buy at the grocery to use on dishes, but it's still easily cut with a scissors. Like other "grits" of Scotchbrite, it will hold a fair amount of liquid, so you can use it along with the Krud Kutter to break the surface tension and get it soaking into the rusty metal.
The Krud Kutter was about $5 for an 8 oz. container. I have also bought it in a pump-spray bottle, which I think would be the way to go if you had something really big to work on, like a big table saw. It tends to bead up on metal surfaces when you spray it. The directions repeatedly refer to "breaking the surface tension," and emphasize the importance of removing grease beforehand. I can second that, though with the tough Scotchbrite you can scrub through a minor coating of oil if you invest some elbow grease. The Krud Kutter cleans up with water and there are no fumes, just a moderate "chemical" odor. I wore some good plastic gloves to work with it. On the dry surface rust, I applied the Krud Kutter with a cheap paintbrush and revisited the area a few times, then wiped off all the residue I could with a shop rag.