I guess everyone does things different. I canít stand etching primer. My process is to clean any bare metal by sand blasting it then use PPG metal prep to bring out any impurities. I will follow that with PPG zinc chromate. Two restorations I did in 88 are still in the same condition as when they left my shop 21 years ago. I live in Upstate NY.
I agree with your follow-up in sanding. However, I donít use a DA for feathering glasswork or primer. Feathering old paintwork, yes. As far as putty, I use good old Nitro Stan. Yes, Iím a relic of the past. My methods are old but my career and success has been built on my experience. Itís hard for me to abandon whatís worked best for me over the years.