did you have the inside hull and underneath sodablasted also?
only way to neatralize is water (warm water works best) and dawn dish soap or simple green. scrub with a red scotch brite and keep the metal wet as you are scrubbing.....do not let the panels dry up as you are washing...keep them wet until final rinse and after rinsing blow dry with clean air...blow into all the little holes and crevaces. once the metal is clean you will need to sand it with 100g/180g to give the primer something to bite to as soda doesn't profile the metal. clean with wax and grease remover and epoxy prime.
DO NOT use laquer thinner to clean the metal...sanding wont clean the soda either..no matter what you use.
the place didn't give him detailed instructions because most places dont know the detailed instructions on how to neatralize...they have no idea what the soda does to the metal and dont really care to know. main reason soda has revieved a bad wrap....i've used it on many show cars with ZERO problems. does it add a little more labor to the job? yes but in many instances the soda is quicker than other medias. i've done it both ways and no one can argue with me that soda is just sooooooo much more time consuming than general media blasting.....how long do you usualy spend blowing and blowing and blowing other medias out of the car? i'm STILL blowing the stuff out up untill it hits the paint booth for paint.
2 of the main problems from soda, 1 is not properly neatralizing.....will show up 6 months after painted when the car is sitting outside in the sun....small bubbles start to appear over the top surfaces of the car.
2nd is soda coming out from overlapped welded areas like doorjambs, floors, etc. it gets down in those cracks and is extremely hard to get out. I only have exterior panels sodablasted, if they need to be. We've since quit using soda on these areas because of that, besides thats where a lot of sanding labor comes in also, trying to sand all those little areas of metal to get the primer to bite.
as far as primers go, many manufacturers warn against using soda for the problems i've described above....just too much headache for them to deal with soda they just say dont use it....these soda comapanies just never put the time and effort into explaining how treat the substrates after being blasted.
I've used sikkens epoxy over soda cars for years...and have recently started using spi epoxy, and have used it over soda with no problems. best thing to do is contact the company you are going to use and explain the situation. more than likely they aren't going to be happy, but when properly neatralized and sanded, the epoxy with stick and you wont have any problems. Zero.