I have completed the welding/finish work on my GT flares and have primed them on the outside with rattle can auto primer. By finish work I mean I've done skim coats of bondo and glaze and have primed. I have the car outside under a blue tarp but it's the rainy season in Florida and was wondering should I spray some sealer on the fenders to prevent rust? I'm assuming the primer is porous? Or should I hit it with some rattle can paint? I don't expect to be ready to put down real paint until the end of the year. So what do you think guys?

I'm at this point too. The metal around the welds on the inside have already started to rust. I've been debating on doing the underside in POR.

ABSOLUTELY !! Rattle can primers offer NO protection. All they are good for is getting a uniform color and making yourself feel all warm and fuzzy until the rust starts to show.....and it will. You MUST get a coat of REAL auto sealer on it as soon as you can. A cheap but fairly effective brand to use is Nason. It is Duponts cheapo line and will do fine for a long term storage situation.

Billy since rust has already started on yoursd you would be BEST off to sandblast if possible or at the very leat wire brush the affected aera then give a a good coat of OSPHO (FOLLOW THE DIRECTIONS !) then then a coat of sealer.

Alrighty, one more time.

Spray paint from rattlecans is crap.

The nozzle design is so poor a lot of the paint partially dries before hitting the car and you end up with basically a bunch of little balls all stuck together with gaps between the balls.

Grey, red, and black primer is porous. The only good primer is a catalyzed 2 part self etching primer like Dupont variprime, which forms a waterproof seal and needs to be sprayed with a paint gun.

What does this mean to you? As a former Floridian with beach experience, spray the can crap, go in for lunch, and come back out to find it rusting through the primer. Spray the Variprime and you can wait as long as you want.

Ken

I'm not seeing any rust yet and it has been about a month since I finished priming. I did treat both the inside and outside welds with Ospho and then I used automotive seam sealer on the inside and a oil based primer with several coats. But on the outside I just used auto rattle can primer. Looks like I'll be buying some sealer. Thanks guys.

Here is how I did the inside of mine....

I removed all the paint and undercoating from the inside. Once the body work was done on the flares a good quality seam sealer was used on the entire seam length followed by a good epoxy primer.

Once everything dried, a rubberized coating (similar to truck bed lining) was sprayed in. The flat areas that are especially susceptiple to rock dings were sprayed quite heavily and probably about 1/8" thick or more.

If you skip the rubberized portion, you will most likely regret it since rocks will fly up leaving a nice star in your new paint job from the inside out.

On the outside epoxy primer was used immediately following body work.

I would avoid rattle can primer. Even the really good quality products right from the paint store caused some problems when paint went over it.

Another important factor is to use self etching primer when used directly on steel. POR also needs to be on an etched surface when directly applied on the steel. All this while assuming you used thinner to wipe the area clean before priming.

And you may not for another few years. I've seen plenty of old paint jobs that are littered with little bubbles. After sanding you can see how the whole surface was covered with small rust patches. Much like this image.

Another issue with crap that comes out of a rattle can is future paint interaction. I've seen it time and time again. I used to spray paint on stuff I had welded up to protect it. The paint shop I use kept kicking me in ass later because they had to remove it all later. If they didn't remove it the paint would bubble, fish-eye, etc. All the bad stuff. Now I leave everything bare and take it directly to the paint shop for proper protection/prep/paint.

Good luck.