What's the proper way to sand and paint a steel front door?

[EdL]

Last one I had painted, took it to a small 1 man autobody shop. Had him shoot it with farm store tractor enamel with hardener...cost me $100.

Ed

[fixtureman]

When we painted steel doors we would use auto paint

[brianwelch]

A good topside marine paint might be worth investigating as well...ultimately I suspect you will want to get back to bare substrate/metal and start with the proper primer...

[Bill Wilson]

I think you will have a hard time feathering in those chips, using any kind of rotary, flapper sander.  I would sand by hand or perhaps with an oscillating detail sander.  Even then, unless you really work at it, it will telegraph through the new paint.  Any surface defect on a metal door will show through the paint.  That's why good autobody work is so expensive.

I've used Rustoleum and it seems to hold up well.  I apply it with a small foam roller.  Like Willylou mentioned, it leaves a bit of an orange peel texture, but I think it looks better than brush strokes, which are virtually unavoidable.

[Cooler]

I used Rustoleum in the Aerosol.  I removed the door and laid it flat to prevent runs.  I sprayed a heavy coat and allowed it to self-level.

Wait at least 24 hours for recoat, as the second coat can wrinkle the first coat.  Two cans of color will be enough for a front door.  But the color selection is quite limited.

The are offering some new (modern) colors.  The "color pages" show a full screen of the color as you scroll down.

https://www.rustoleum.com/pages/color-wa...lor-scroll

[John Mihich]

I hate trying to feather sand on metal.  Can be done but I just don't like it. Must be the auto body worker in me. I strip metal doors and start with bare metal.  Then I spray metal primer.  The last door I did I then sprayed duration.  I have used Rustolium also - that works well.  I also always spray with the door flat.

[Robert Adams]

When we painted steel doors we would use auto paint

            This is the best approach. It is steel treat it like steel. Do not under any circumstances paint a metal door with latex or any waterbased paint as you will not like the durability of it. 

             Clean it with wax and grease remover (AKA surface wash)
             Sand it clean
             Clean it with wax and grease remover
             Epoxy prime it
             Fill dents with filler and sand
             Clean again
             Spray a coat of 2k high build primer (if you want it perfect)
             Sand again
             Clean again
             Spray with acrylic enamel(real acrylic enamel not that junk water based paint the house paint stores call that)/single stage urethane or base clear if you want shiny. (can add flatteners to the clear)
             Cut and Buff the clear if going for shiny.

              Basically the same as painting a car. That list makes it sound like allot more work than it is but it is still allot of work. For a door you can condense that a little or skip steps. You can get any color automotive paint and primers in spray cans. The paint shop will mix it up and put it in s special spray can. When you go to use it the cap is pressed into the bottom of the can to release the hardener into the can. Shake it up and spray but it is only good for 30 minutes or so. 
   
               If you want to go quick and easy... Rustoleum can be mixed with acrylic enamel hardener like an acrylic enamel. Not as good but better than out of the can and it cures much faster. 

               In short no water based paints (water borne automotive paint is different but expensive and rarely used) and no regular rattle can paint should ever touch a metal door.

[Snipe Hunter]

I hate trying to feather sand on metal.  Can be done but I just don't like it. Must be the auto body worker in me.  I strip metal doors and start with bare metal.  Then I spray metal primer.  The last door I did I then sprayed duration.  I have used Rustolium also - that works well.  I also always spray with the door flat.

Always use a flat block. And, it helps if you dust on some high build primer now and then to help fill the edges. Or buy a "flowable 2k body filler like "Icing" or "Evercoat Metal Glaze" or "Evercoat Easy Sand" I'm partial to Easy Sand, because it sets fast and sands easy. Ready to sand in 15-20 min on a warm day. A little longer when it's cooler. Icing is s little runny and Metal Glaze is tough as nails and hard to sand. I have to feather out a lot of paint on metal. I don't use a powered sander. A good flat block is best. Power for material removal, block sand for a finish-able surface. Flat or curved surface, use a block.

Latex sands poorly and gums up abrasive paper. I give it a quick sanding w/ 80 grit past were any paint has failed (peeled) and fill it. Then sand it smooth. with a block. For drywall, I just use hot 20 minute drywall mud and sand it smooth when dry.