Painting moldings- black, clear or other.

[M5BB]

I'm a professional wood finisher and I know you think... so what?
We'll it also help's me do a pretty damm good job of finishing metal and fiberglass. You should see my sailboat.
Aluminum moldings have to be primed with an etching type primer. That's the only way the paint will stay for any length of time. My black bumpers which many have seen were done that way. Sanding is important but you don't want to go so fine with the paper (no steelwool) that the surface is so slippery that nothing will stick to it.
The paint needs a tooth to hang on to. 400 wet sanding would be best. One other thing, before you start sanding wipe down all the molding with alcohol that you can get at the H store. And don't drink this stuff it will kill you. This will remove any wax, silicone (bad stuff for paint) or oil before you start sanding. You don't want to sand this stuff right into the surface.
If you think you might be too close to your paint, do the masking before you start sanding. You might have to replace some of it before painting but it's better than scratching your paint.
The primer Dupli-Color Self Etching Primer (it's green)can then be applied and then wet sand that with 600 paper. Careful don't sand it all off. The object is to get it smooth and fill any tiny voids. Put a few drops of dishwashing soap in a bucket of water and then dip the paper in the bucket.This helps the paper slide along and carry away the particles. Keep the water flowing or the paper will clog up and not sand. Don't be cheap about the paper either. It does not last very long and you'll just be waisting your time.
Take great care and time masking. Use the blue or green masking tape from the local H depot. Use it along the edges of the metal then use brown masking paper which comes in rolls at the H depot and run that along the first row of tape you applied and tape it to the first row of tape that is next to the metal. This masking paper is 12-15" wide so you should then put more rows or plastic sheeting to cover the body. You don't want primer and black paint on your white car.
Don't use newspaper as the ink can transfer to your paint.

Once you get a really good base coat of primer
Buy some Dupli-Color Trim Paint from NAPA or Pep Boys (there could be other suppliers). This is very professional paint in cans. The nozzle's are amazing.
You can change the fan spray to any angle you want so your hand movement will correspond with the angle of the molding you are working on. You can also wet sand this if you have some dust or problem areas. Oh, I forgot to tell you, get a tack rag at the H store and wipe the area very carefully right before you spray. This will pick up any dirt and remove it from the surface. Pay attention to the weather. Read the frigging can!!
If it's very high humidity your paint will not stick. Don't paint in the sun. The paint will dry to fast and look like flat black paint.
If it's a little cool out like 60 or so warm up the cans in front of a heater. Be careful not to get them to close as they will blow up! Go easy on the application, runs are a mess and can ruin everything you have done, trying to get them out. 3-4 fine coats are much better. Same with the primer.
Test spray on a smooth piece of cardboard so you can see how much paint comes out of the nozzle.
Questions??? Email me and I'll do my best to help you out. I can even give you a phone number as my typing skills suck.
I have used the basics of this process to put a clear finish on my chrome moldings that are beyond polish. The clear fills all the tiny cracks and makes them look clear and shiny again.
Clear acrylic made by guess who??? Dupli-Color.
Good luck and let me know how you do?
Man, that's more than I've typed in months.

[John in VA]

...Buy some Du-Plo Trim Paint from NAPA or Pep Boys (there could be others). This is very professional paint in cans. The nozzle's are amazing.

Do you mean Dupli-Color? I thought Duplo was something to do with Legos.

[M5BB]

Boy did you get me on that one.
I have grandchildren.
Guess I need to do some editing.
What did you think otherwise?

[John in VA]

Sounds good. I've never sprayed clear on dulled aluminum trim, but might give it a try.
I have seen it look better after an application of 3-in-1 or WD-40. It makes a mess, but looks good for the show!

[Mike W.]

I know more than most about painting, but way less than a pro, and I agree with pretty much everything you said. My only question is do you like the Dupi-Color trim black better than SEM trim black, which I've always thought of as the standard.

[M5BB]

You know I haven't used the SEM Black.
It's harder to find (order) and I've had such good experience with the Dupli-Color and especially the nozzles. They spray as good as my $150 spray gun.
It's all about what you are comfortable with and have experience. This procedure will work with any good quality paint that is made for this use.
I use the Dupli-color products in the my wood working business too.

[mogie]

I've used several brands of trim paint. I was not impressed above all others with the SEM paint. For the price i don't think it was any better than others. A local place here carries all the SEM products so I've tried the trim and the etching primer and I'm not all that impressed.

The Duplicolor trim paint was very easy to shoot, dries pretty fast and overall it adheres very well when properly prepared. Its also pretty versatile on what surfaces you spray it on. Its very good both on plastic and metals.

A new trim paint I've started using is Transtar trim paint. Very smooth application, very quick dry time. So far i can't say how it holds up over time but thats what I'm using now adays.

[M5BB]

Can a Beamter make this a FAQ.
Hate to see it get lost.