I purchased some 48 doors that had been sitting outside for many years. There actually in very good shape but have complete surface rust, inside and out. I can deal with the outside rust I can get to but what do I do about the rust on the inside of the doors?

 

I would use a rust converter and then paint. are you down to bare door with all the window gear out?

 

Just started on the outside yesterday. There are a host of products, Por 15, 3M rust fighter etc. Just wondered what your all best advice was. I'm thinking that brushing the Por 15 inside the doors might be my best bet.

 

POR-15 is a paint, and while it does do a good job with rust encapsulation, it does not work so well on flaky/powdery rust. I personally use KBS products. They make a rust dissolver and cleaner that can easily be sprayed on and rinsed off leaving a solid surface for the Rust Seal. I just bought a 5 gal pail of Evaporust but haven't used it yet, it is touted to be an environmentally friendly product that can be used and reused.

 

Plain old phosphoric acid, sometimes sold as a concrete etcher at Home Depot/Lowes, available under the Ospho name brand at Ace/True Value - perfect as the initial rust conversion/removal process.

After that, if it's me and it's an unseen area such as a door interior, I use old fashioned oil-based rustoleum brush on as the final coat.

 

If you haven't used it yet Charlie I'd be careful about endorsing it. I have serious doubts that anything environmentally friendly does a good job with anything as bad as that described. An acid dip is what you really need there. Other benefit is you lose a bit of weight. That technique was used a lot in motorsport where production panels had to be used. 😀.

 

Acid dip is correct. Any of those rust converters are gimmicks. They slow it down a little but only for a while.

 

I have been using what Scotty recommended to me, klean strip prep and etch at Home Depot. I have a soak tank that I use on small parts and a spray bottle for the big pieces. It works great followed by a baking powder water solution to neatralize then a wire wheel or dremel stainless brush polish. I hardly use my blast cabinet now. The acid soak is especially great on moving pieces such as the door internals as the grit gets into the gears and bearings. One caution though, if it's rust, it will eat it away!

For my doors I used that, my portable blast gun, followed by a POR coating and rust oleum way up into the tough to reach crevices.

JB

 

Eastwood Fast Etch is my light/medium surface rust remover of choice. I've been using it for years. It's basically phosphoric acid, and technically it's more of a rust converter than remover - phosphoric acid turns iron oxide into iron phosphate, which is pretty stable, chemically speaking. Another upside is that the product leaves a thin protective coating of phosphate on the surface metal.

One downside of acid preps like Fast Etch/phosphoric acid is that they can darken some low-carbon steels, but if you are painting the parts anyway, this shouldn't be an issue.

I've also used Evapo-Rust. I haven't used it as extensively as I have Fast Etch, but it does seem to work as advertised. I left some seat fasteners soaking overnight, and was really surprised at how clean they were afterwards.

I think either of these products would be a workable home solution to your door rust removal.

 

The Evaporust works. I have used it numerous times on original bolts and other parts on my 53 and they come out looking like new. I also took the original brake calipers from the 2005 CV IFS from an Indiana detectives car (lots of rust), and the Evaporust soaking removed all the rust. A little media blasting afterwards, then some paint, and I have calipers that look better than new.

 

Eastwood has a rust converter that cleans up with water but one it drys it is quite hard. It has held up well on my truck frame for 3+ years.

 

Here is my method of rust removal....



You can add some Citric Acid (used for canning) too.

I mix 1 gallon ZEP with 2 gallons of water... I dump in an entire bottle of dry citric acid... It takes several days to get all the rust off but it does the job. I then spray the part with Metal Prep to prevent flash rust.

I will be using a small kiddie pool to do the doors.

The piece you see has been soaking for about a day and a half.

This works well on sheet metal, but best not use it on cast metals like brake drum's and the like, as it can makes those metals brittle.

HTH

/Bob