Total NAC: Rust paint

[Marc Boucher]

This group has always seemed to have technical knowledge on all fronts so I'll take a shot at this.

Need to repaint rusty metal railings outdoor.  Have a number of options recommend to me.  Any thoughts among these?


1.) top of the line
a.) remove all rust-sand to bare metal
b.) apply Zinc for cathodic protection (can you recommend a few names of products)
c.) Anodic passaviation - 100% acrylic exterior membrane paint (can you recommend a few names of products?

2.) The method recommended by the PPG rep (with the caveat that it had to be done right)
a.) Remove loose rust then apply 2 coats of rust converter
b.) apply 2 coats of their epoxy paint (Amerlock)
c.) apply 1 coat of their polyurethane paint (Amershield). (PPG also makes Pithane which is Urethane based...I'll check why he didn't mention that)

3.) Benjamin Moore Alkyd Enamel KP22 (Industrial productwith Titanium Dioxide, 394 g/L VOC) (an alternative is Rustoleum)
a.) Remove loose rust then apply 2 coats of rust converter 
b.) paint with BM Industrial Enamel KP22. The painter recommends 1.5 coats of enamel...1 coat, then touch ups.

4.) Benjamin Moore Exterior Alkyd Enamel 133 (although the name says exterior, the spec sheet describes it as Interior/Exterior...so presumably it’s not a high VOC content, but that’s not listed on the spec sheet.
a.) Remove loose rust then apply 2 coats of rust converter 
b.) paint with BM Exterior Alkyd Enamel. The painter recommends 1.5 coats of enamel...1 coat, then touch ups.

5.) Local brand of Exterior Oil Based Enamel. Our painter points out that Benjamin Moore is always more expensive than local brands ($70/gallon for BM vs. $50/gallon for a Canadian brand (Sico). He feels that the added expense isn't justified given that we're already using multiple coats of rust converter. Since he's being paid for labor separate than for paint, his motivation for recommending the less expensive paint would not be to maximize how much he takes home from the job. 
a.) Remove loose rust then apply 2 coats of rust converter 
b.) paint with the oil-based enamel. The painter recommends 1.5 coats of enamel...1 coat, then touch ups.

Thanks for any thoughts 

MC