We have an external metal door that has rust showing through the paint. I want to re-paint the door, but I want to remove the rust first and then use the right paint to prevent it from coming back.
I would imagine using steel wool is a good idea. Is there a solvent (i.e. naval jelly) or something that I should use as well? Then, use a primer and rustolium (sp?)??
Thanks. Any tips are appreciated.
Depends on the application. If this is a door to a shed, then knock off the rust and paint it with good enamel and it will last for several years. If it's your front door, then remove the hinge pins and take the door to be blasted with plastic media, then paint with "metal prep" which leaves a coating of iron phosphate, then use a real good quality primer (I'd use red lead if you can still get it) and then top quality enamel.
Rust removal can be done in lots of ways. For bigger surfaces like a door I use a 4-1/2" angle grinder with a cup wheel with knotted stainless wires. The cup wheels aren't particularly cheap but the stainless ones last a lot longer. Forget the steel wool. You can also sand the door with a belt sander using
240 grit belts or higher. The paint that's on the door is likely to be hard to remove. You don't have to remove it all! What's on, intact, and tight is good to leave on if you aren't striving for the ultimate in cosmetics.Grant
Rileyesi wrote:
I had the same problem with the bottom of my garage door. I removed the rust with a scotchbrite pad and some WD-40. Then I removed the WD-40 with simple green. It has been about 4 months since repainting, and no rust has shown through.
Visit an autobody supply place and look for "Rust Mort". It's water-based stuff you can apply with a rag or a brush (wearing rubber gloves and safety glasses) that will convert rust to a tightly-adherent black phosphate. Follow the directions. Remove the door to do this, don't do it "in place".
Then, if you or anyone you know has spray equipment, shoot the door with an automotive zinc-chromate based two-part epoxy primer. That stuff is pricey but it is extremely durable. You can put about any finish coat you like over the epoxy priimer.
This is the best way to do the job, as long as there are not delicate items on the door near the rust. A good source of the wire wheels Grant was speaking of is Harbor Freight. ALWAYS WEAR EYE PROTECTION WORKING WITH AN ANGLE GRINDER. Especially with wire wheels- they lose a lot of wire, at over 100 MPH, usually right at your face! :-)
While you're looking at the Harbor Freight catalog, AND if you have a fair-enough air compressor (3HP or so) you might want to consider getting a sand-blaster... not a cabinet, but the kind that feed out of a bucket. Especially if there is filigree, or what-not on the door that could be destroyed by the grinding of the angle grinder.
Just my random thoughts. K.C
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