I’m doing a lot of welding and tidying up underneath my car. All the info online for classic and restoration work is saying to use epoxy primer. I was in my local motor factors this morning, fyfes for anyone in Northern Ireland, and they had no idea what I was on about. They did have red oxide primer though. Is this as good? I’ve used this on heavy steel, artic trailers and the likes but is it any good for my “classic” porsche?