I spent a long time cleaning/ sanding my swivels on a donor axle to fit to mine.
Used a little hand held shot blaster and wire wheel on a drill to clean them up.
Mixed up some jb weld and spread evenly, left to dry for 24 hours, then sanded smooth and reapplied in a few areas till the whole sphere was smooth.
I put the axle in along with all the arms/ rods etc to be blasted and powder coated. I didn’t stipulate not to blast and paint the spheres, so I got it back and they’d been powder coated!
Rather than sand down to metal, I wet sanded the slight orange peel down to smooth then just left them. This way the non swept metal areas don’t start rusting again. So far so good, it’s a really hard durable paint.