red58 I am still going to disagree. In order for paint to adhere you need acid on the metal. So if the soda leaves an alkaline coating that would be why soda blasting has been reported as causing problems with paint adhesion. Blasting soda has a Ph value of 8.4 which if I remember accurately indicates it is alkaline. To neutralize it you would have to use an acid.
To take your next point. It really doesn't matter if it's a growing industry. If paint manufacturers included the likes of BASF recommend against using it, then obviously there is something that can cause issues.
