I would use rust converter, the kind that stinks, turns purple then black epoxy when done.

 

If its mild surface rust only, I’m a huge fan of phosphoric acid and Master Series. Some of that appears to be bubbling or at least lumpy,...maybe it’s just the angle though.

Sand it down and post up a few pictures.

When you say it’s finished, how finished are you referring to, and why not knock out any rust first?

 

I use this- brush it on with 2 coats, short wait in between, wait 24 hrs, than top coat as desired. It dries to a hard coating and can be painted over without having to scuff up. I've used it on trannies, axles, floors, inside doors, etc- very happy with it. Yes it stinks, and yes it stains, so wear rubber gloves and be careful. In the event you get it onto a painted surface, wipe it off while it's wet- no problem.

 

I use this- brush it on with 2 coats, short wait in between, wait 24 hrs, than top coat as desired. It dries to a hard coating and can be painted over without having to scuff up. I've used it on trannies, axles, floors, inside doors, etc- very happy with it. Yes it stinks, and yes it stains, so wear rubber gloves and be careful. In the event you get it onto a painted surface, wipe it off while it's wet- no problem.

The thing that scares me about this stuff is in the fine print it says you can't put it on non-rusted surfaces or it could cause rust! that would be a problem for me since a lot of it is still good steel and its just on the surface.

Doing some more digging it appears that Corroseal is a good product that might fit the requirement. Has anyone used that?

 

As it's inside the door, you might also consider Por 15. My experience is that it doesn't take a top coat very well. Also, it does seem to discolor a bit over time. But, I've never had a problem with it rusting through.

If you were going to use it somewhere that needed a topcoat I would recommend spraying the first layer of top coat when the por 15 almost dry. I seem to get better adhesion that way.

It's expensive but a lot cheaper than new doors.
POR-15 Rust Preventive Coating - Stop Rust Permanently

 

Por-15



I recently restored the back seat to my 1966 Mustang. The seat frame was extremely rusty. I would sand and blow out what you can. I used a POR-15 metal prep which neutralizes the rust and preps the metal for adhesion. I then followed up by brushing on the Pro-15 rust preventive semi gloss black paint. The paint works as a rust encapsulator and also prevents future rust. I'm impressed with its adhesion and durability. However, I'm told that it will break down to UV light, so topcoat if exposed to the sun, but that doesn't sound like it will be an issue for the inside of your doors. You could topcoat with a rattle can paint, like Estwood Chassis black or even go an additional step and apply lizard skin.

Stop Rust with POR-15 - Professional automotive and industrial coatings for permanent corrosion protection.

 

Picklex

 

Here's how I treated the rust inside my door...

1967 Mustang Restoration: New product review: Mastercoat Metal Prep

 

Short of acid-dipping or submerging for electrolysis you'll be hard-pressed to "encapsulate" the existing rust and stopping moisture from getting underneath the coating from the edges. I think I'd remove as much loose stuff as possible, hit with a spray of Picklex20, then give a couple coats of Kirker/Eastwood epoxy primer (brush on) and when everthing is cured douse it with Fluid Film.

 

Eastwood's rust encapsulator is a superior product VS the POR-15, IMHO , and you can paint on top of it.

That said, I would first bush on some phosphoric acid and get rid of all the rust I could reach, then neutralize, then use the Eastwood rust encapsulator .

Z

 

This is how I did my mustang doors.

Also, I painted the inside of a new set of repop doors for my 67 C10 back in 2005 with eastwood rust encapsulator, the truck has sat outside 24/7 since, and I recently had the door panels off to fix a door latch and there was ZERO rust inside the door 12 years later.

 

Thanks for the suggestions guys. I think trying to get as much off with a wire brush as I can is probably the first order of business from what I've learned. I also got this product suggestion from a different source - anyone have experience with this? https://www.theruststore.com/Rust-Bullet-Automotive-Formula-P370C112.aspx

 

Google POR15 and you’ll see many, many fans and haters. It seems pretty split on the results. Some have reported following the prep exactly and having it peel off in huge sheets. :surprise:

I wasn’t going to take a chance, go with the Master Series.

 

I would mask off or plug up any possible danger zones.

Z

 

The only negative to rust encapsulator is that if you use it on suspension/frames if you actually drive your car exposure to the sun and elements does fade/wear the finish, so if using in an exterior area it needs to be topcoated.

I also have rust encapsulator spots all over my garage floor and driveway :lol:

As far as it running out of the drain holes, it actually drives pretty fast, so if you wipe the runs off your paint when they happen it will come right off. The directions used to say you could thin it with mineral spirits, which will also wipe it off any surface when it's wet. Just keep an eye on the drips for a bit after you're done.

Edit: they must have changed the formula a bit, I was looking up info on it just now and found this:

• Superior durability (tested to 500 hours in a salt-spray chamber)
• UV Resistance - a topcoat is not needed
• Epoxy-fortified for better adhesion and topcoat compatibility
• Penetrates deeper to prevent rust from spreading or forming, even in hard-to-reach areas
• Requires minimal prep and cures fast
• Available in convenient spray aerosol or brush on quart and gallon sizes
• Heat resistant to 400F

 

Use a drop cloth (plastic) under the doors to protect your floor/driveway, etc. I've found that plastic drinking straws inserted through drain holes so that they stick through by an inch or more inside work well to prevent the coating from running out the drains. Start with a light amount and let it set up between the straw and metal to make a seal then apply heavier. When it's fully cured yank out the straws to re-open the drains.