Fiberglass resin for touchup spots?

[Varsity]

I really haven't found too much info for this stuff on bodywork, just mainly for audio and stuff so I figured I'd ask. Within a week or so, I am planning to tackle some rust spots on my truck and looking at the fiberglass resin seems like the best bet for me currently. Now to get this out of the way, I know this won't "cure" rust and the proper way requires new sheetmetal and cutting, etc. I'm not looking for professional bodyshop results or anything, just an honest attempt at trying to tame rust before it gets too bad.

My main question is this. I roughly understand the whole process with the hardener, fabric and such, but I'm more concerned about prep. When/if I come across a rust spot, whether its bubbled paint or an actual break, is it better to not touch the rust and spray it with some rust neutralizer or dissolver or to sand down the rust as much as possible before taking care of the fiberglassing? I'm old fashioned and assumed the second one, but after taking a look at the rust dissolvers, I'm kinda torn on what to do. I'm left with a couple of "gray areas" with this stuff.

I'm pretty much just tackling the spots under the trim, like the rockers and around the fenders which end up being covered anyways. Anyone have an tips or suggestions on going this route? I really do appreciate it.

 

[MONMIX]

either.
Bottom line is not doing it right will have consequences of one kind or another eventually.

Scrape and grind out the loose crap as much as possible. Treat whats left and then slop on the filler.

 

[Varsity]

Yeah, kinda figured I wouldn't get any praise from the pros on this choice of bodywork, but oh well.

I do appreciate your input though MONMIX, it means a lot to get some type of response from someone who obviously knows very well what they're doing with bodywork. I think I'll just sand down and get every little bit I possibly can, then just treat with the fiberglass. I by no means expect or desire pro results from this, but hopefully this will last some time and once it pops through again, I can worry about it then.