After doing a search on "rusty tops" ,popular opinion seems to be removing all the rust and using epoxy primer.Some time ago ,I was in the city and bought what the auto paint store recommended for my 66 vinyl top typical rust problem.They sold me Nason etching primer and reducer and some high build primer with instructions to sand/grind surface smooth,not necessary to remove all rust, shoot etch primer and within 4 hours ,shoot high build primer and block it,repeat until its smooth.Now the question,is this the new improved way to treat these rust pits ,or throw this stuff out and start over?...not convenient because I'm a long way from supply store...but I want it right.
I'm also a little confused about using /not using a prep and prime type phosphoric acid (Jasco) and at what stage of this operation using Bondo on the welded metal repaired areas around the sail panels and window channels....bare metal or on the etch primer .
Sorry for the length .This is my first attempt at this level of repair so the details are important.
Thanks Harold

Etch primer is not a substitute for removing or treating rust.
The metal conditioner (phosphoric acid) is also not really used for treating rust, but for cleaning the metal of minor "surface" rust, etc. prior to priming.
You've got to either remove the rust or use a rust converter first, then use a premixed fiberglass on your repairs and rust pits, finish with body filler.
Then you can use the etch primer on the bare metal only (it's OK to get some on the fillers) and follow with fill primer.

I assumed the Jasco product(from PPG industrial paint store) was a rust convertor, not just a cleaner.Please mention some brand name examples of a rust convertor and "premixed fiberglas"....is this something with fine fibers or chopped cloth rather than just a gel product?

i use Permatex (pn 81387) rust converter myself but, there's a number of them out there. I think a lot of guys are using Rust-Mort. I'm not familiar with the Jasco you've got, do the instructions say it will convert the rust?
Premixed 'glass is a fiberglass based body filler, I prefer the short strand ones. I think all the body filler brands make it.

I will re-read the Jasco label tonite...I 'm afraid its not auto paint quality,that it might bleed thru after setting in the sun in the future.I will look for the Permatex product.
I finally reached an English speaking person at the paint store today.He advised a urethane type high build primer rather than a filler.I guess its all works and only time will tell if you made a wise choice.I hate learning this way.
Thanks for your input.
Harold

If that high build primer that you bought is Nason 421-19 (which needs 483-87 activator), that is a two part urethane. If so, then along with the etch primer that you already have, you've got a good foundation to paint on.
I'm not sure if you (or your English speaking buddy :)) mean to fill the rust pits with primer. Not a good idea, better to use a body filler or the premixed ,glass.

The original intent was to fit the pits with primer,but after sanding and actually being able to see how deep they are,I had second thoughts and started this search.I belive you have stepped up and cleared the concerns.I feel better about the current plan.
This might have been a harder question than I first thought....there were a lot of looks but no comments.I do appreciate your help.
Harold