POR-15 etching primer

[bahamasair]

Hi guys I have a couple of quick questions. I painted my frame with por15 and now have to use an etching primer so I can top coat. Do I have to scuff the frame for the etching primer or will it etch it and stick by its self. Id rather not have to sand the whole frame and even if I do there is some pitting so the sand paper wont get into the small pits. It seems like Ive been working on this ******** thing forever now and I just want it done
Also while Im here on a totally unrelated note I got 1/2" ARP studs for my front hubs they have a .625'' Knurl. Does this mean I have to drill the holes out to .625 or is the hole supposed to be smaller than the .625 knurl size?
Thanks for any help

 

[randycj7]

I would measure the knurl if it is .625 out side I would drill the holes out to about .600 or .610 That is my opinion

 

[Franz©]

The whole theory behind POR 15 is that it employs it's phosphoric acid component to chemicly convert iron oxide to iron phosphate. Unfortunately POR 15 is an overpriced halfassed conversion system that only hangs on a few years. If you had done a real phosphoric conversion, you wouldn't need a primer.

Take the frame someplace and have the overpriced **** media blasted off, then use your etching primer.

 

[67 455 Bird ragtop]

The POR-15 etching primer is different from normal etching primer. It is made to etch POR-15 so a normal top coat/paint will cover it. This is a little different than the normal self etching primers you would use on bare/blasted metal.

I used to use POR-15 but didn't like it's longevity. I found a product called Master Series to be a much better and true rust encapulator. Plus you can top coat directly on top of it. But I think you have to do it with in a certain time limit.

Hope this helps.

 

[bahamasair]

Thanks for the replies guys. There is no way Im going to blast this off after all the **** I went through to get it to where it is now lol. Im using a regular etching primer which is what Por used to recommend before they came out with their own etching primer. I guess Ill just scuff the por and prime it.

 

[Franz©]

The purpose of primer is to provide an adhesive layer between metal and enamel.
Etching primers generally dry entirely too quickly to effectively etch steel, and in my opinion the very nomenclature is misleading. Etching prior to priming is a superior process in that it gives the primer additional purchase on the steel.

IF the POR primer is there I really can't find a reason to need a second primer atop the POR primer, not can I find a reason for the second coat to be an etching primer.