I used Seymour Zinc Phosphate to cover the bare metal of my car after I removed the paint. The can has the worst finger cramping spray nozzle I ever used, which really surprised me being a Seymour. product. Aside from that, it worked well for the year or so it was on before it went for paint. I'm in the other corner of PA and my garage has a little heat, but not enough to paint in. I got a couple florescent lights I shine on stuff before I paint it. Electric heaters work ok but the kerosene one was the best.
https://www.seymourpaint.com/product...sphate-primer/