recently bought a bike with a Silca pump, poor rattle-can respray.
I removed the paint, with lacquer thinner and primed with automotive primer after wet sanding the barrel to finish off the original foil stamping impressions.
Then Chromabase. Not sure if I will clear it, these pumps originally had a low luster finish.
The Chromabase shrinks down very well.
I opened up the pump so there was about 9" of the plunger shaft exposed and masked that and the brass end fitting.
After painting removed the tape covering the end, and set the pump vertically on a nail.