Great work so far! One thing -- you'll want to remove the headset cups before sandblasting, otherwise they're likely to suffer damage, and you'd need to replace the headset. You can either make tools (I did not, but I know there are videos covering this) or use a tool at a local bike co-op. This is one where it makes sense to use the right tool (either homemade or borrowed) because the fit and quality of the headset can significantly affect ride quality.