After washing my car today I decided to open the hatch just to let things dry out faster, and to my horror saw some rust on the bottom of the hatch lid in the center.

See the pics.

The car is garage kept and I never drive it in the rain any more. (I have in the past though)

I tapped on the rusty areas and the paint is ready to flake off. I can't tell how deep the rust goes. I'm afraid if I try to remove those 2 black plastic plugs, the rusty metal will just break off around it.

I could spray it with some anti-rust chemicals and then leave it alone.

Scrape off the peeling paint and see what's there, then sand it down / wire brush it, and paint with rustoleum?

Take it to a shop and pay megabucks?


Any thoughts welcome!

Thanks

 

That needs attention soon, before it spreads further.

 

Once you start scraping, prepare to deal with what's underneath. You need to be thinking about what you're going to do, because that's not getting better on it's own.

 

Pretty good chance that's going to be a hole or two when you knock off all the trash. The paint is bubbling because there's rust behind it. If it rusted from the edge it might not be all the way through, if it came from the inside out, the paint is probably all that's holding it together.

If the steel underneath is solid, no deep pits or holes, you MIGHT be able to grind all the loose rust off, treat any remaining rust, and seal everything with epoxy primer, or POR15 if you're into shortcuts and brevity. Probably best to assume you'll be cutting and welding. Might be a lot further ahead to just pick up another decklid, have it painted to match the car, and swap it onto your glass at your leisure.

 

I would not hesitate to start chipping away at it, because water trapped beneath the rust layers will continue to cause rust.

And if you end up with some extra holes, simply clean up and cover with POR15 inside and out as much as possible.

If the edges are too big to install the caps, then consider covering the new larger holes with dynamat or similar. But only if you have POR15'd it all to prevent further water and air contact with unpainted surfaces.

Start on small areas to learn your technique, like the smallest least rusted bolt hole, where you can expect to clean up the rust and be left with a round hole for the plug. Then move to larger areas when you have confidence.

And don't worry too much about using a phosphate rust converter IMO. Just get the loose stuff off. And don't make it too smooth with a grinder or powered wire brush. The POR15 will stick fine. Prefers a rougher surface. Goal is to stop water and oxygen contact.

Apply the POR15 in thin multiple coats. Thicker coats result in the layer having small bubbles escape as it cures, causing a rough surface to the finish. Patience. Thin and multiple if you feel the first coat doesn't look like it is covering, which will be the case. The pigment is not reliable indicator for the product. When thin, it looks transparent like you don't have enough on. Just wait for second coat if that is the case.

I had a lot of bubbled surfaces the other week when I slathered it on my floorpan in one location. Was also a very hot day, and I may have had too many fans blowing nearby causing the top surface to cure too quickly.

 

Wow, thanks for the great replies so soon.

This looks like it will be a satisfying, productive repair for me (I hope).

More questions:

I already have a full can of a Rustoleum product called 'Rust Reformer'. Contents are Toluene, Acetone and Xylene. Says it stops rust.

Should I only trust POR 15?

And how can I get the 2 plugs out with a minimum of damage to the plugs and the metal? It seems like they are stuck to the rust pretty well. Would spraying a penetrant on first do any good, like Liquid Wrench? Then try to pry them out with a fingernail or plastic knife edge? They feel like hard plastic, not rubber.

Thanks

 

 

With all due respect, unless you're prepared to have a LARGER HOLE that needs to have new steel welded in, LEAVE IT ALONE. I say this as a person that has poked the rust only to be amazed at how far the damage goes.

Rustoleum has a few Rust converter/coater products. I used a couple of them on the Mustang to stall the rust. It sorta worked, now I can go in and grind the new bubbled rust back down to clean metal and try something different, since the Rustoleum product didn't work for poop. To be fair, it slowed things down for a few years, but really it just covered up the problem.

POR15 is a little better. It's tough, but again you're just slopping some goop over the rust. It's still rust. If you grind through the cured POR15, you'll find nice orange rust. It also only sticks to rust, and maybe etched surfaces (chemically or blasted). It'll flake and peel right off cleaned steel or existing paint. Like you can blow it off with your thumb over the garden hose.

Ospho is a phosphoric acid product. You apply it to the rust, and it eats and chemically converts the rust into an inert substance that can be painted. The catch is that it'll only effect what it actually contacts. So if the rust is very deep, it'll only effect the surface of the rust, kind of like the other products I mentioned.

The only way to REALLY remove rust is to grind or cut it away. Any trace of it that's covered up, has a pretty good chance of coming back eventually. What you have to do is decide how much time and money and effort you want to put into eliminating the rust. If you just zip off the bubbles, and throw some stuff on top, you might buy a few years. If you want it to look like it was never there, and not come back in the short term, you'll have to be a little more aggressive. There's something to be said for leaving the rust alone, it's honest and doesn't look as bad as a poor repair in many cases.