hello, do I understand correctly that a newly sandblasted chassis could be coated with rustseal without using the first 2 steps of the 3 step process?

Absolutely, just blow off the sand dust and begin application. Sandblasting leaves a clean textured surface which allows for great adhesion.

Out of curiosity, would using the first 2 steps on a sandblasted surface make RustSeal work even better? Or no?

It is not recommended to use the AquaKlean and RustBlast on freshly sandblasted steel. It is best to blow off the sand residue with clean air and then apply the RustSeal.

You can find complete instructions for RustSeal here: http://www.kbs-coatings.com/RustSeal-Information-and-Instructions_ep_38-1.html

You can also find the Fix-It Guide which will help you quickly identify the causes of and the recommended solutions for the most common issues that could occur with RustSeal here: http://www.kbs-coatings.com/fix-it-guide-rustseal.html

You can also find Instructional Videos here: http://www.kbs-coatings.com/KBS-Videos_ep_90-1.html

You can also find a Flow Chart for using the KBS 3 Step System here: http://www.kbs-coatings.com/Flow-Chart--RustSeal-on-Steel_ep_87-1.html