I've spent the last 2 hours searching, but I remember a resident expert chiming in on a build thread about how Mazda originally undercoated the 1st gen.

Was the underbody painting the cassis color then coating put on top of it? Or was it undercoated first then color just sprayed over the top of the cassis?

Sorry if someone has this info bookmarked and pissed that I couldn't find it.

 

this is kind of fun, because they still use the same process today. body gets assembled, then it gets dipped in the primer/sealer (its a light color), then they apply the undercoating 3M 08531, then it gets painted body color.

the big difference is that the FC and newer cars are painted with the doors off, so they can install the interior without them in the way. given that all the bolts on the doors are painted on an SA/FB i'm not sure what they did.

in the 1980's it really would have been very similar, Mazda's factory was state of the art back then. the big change is really that they put as little paint on the car as they can now, that unpainted corner of the windshield really bugs me!

 

Cool video, but didn't see any undercoat application.

So the proper restoration would have the undercoat sprayed on top of the e-coat primer, and the color just applied to the 'sunny side' of the car.

I know there is also some disagreement on the anti chip layer on the bottom of the fenders and sides. Any knowledge if that is a separate product or is just started undercoat?

 

on the SA/FB there is a lot of body color paint underneath. its more than overspray, but its not a perfect job either.