Rain all day, a good opportunity to clean up some aluminum engine side covers.
I gave the side covers a light cleaning on the vapour blast cabinet, juts to reveal the overall surface condition, not necessary but it helps to see the surface clearly.
Typical condition of 50+ years old aluminum, some deep scratches and gouges, plenty of pits
I start with 220 grit dry paper in a foam pad random orbital sander, keeping the sander moving all the time and sanding until the damage starts to disappear
Initial sanding shows the depth of the damage, if the casting is thick enough I try and sand all the gouges out, its not always possible
then wet sand with 400 wet/dry on a foam block until the surfaces are rounded and the scratches are removed, then finish with 1000 wet/dry, I go over the surface with the vapour blaster but again its not an absolute requirement, the vapour honing process just further smooths the surface
Then a polishing on the buffer wheel with white polishing stick and finish with a hand rub down with 'Autosol' metal polish
A comparison to another piece, the more I sand the surface with ever finer wet/dry the better the finish, this will do for what I am building
Its messy and time consuming but easy to do and the results are satisfying