I want to keep an anodized red theme to the interior to match the steering wheel quick release and the shifter knob, but still keep it looking like a race car interior, I also would prefer not to have the bright aluminum background to the instrument panel. That being said, I used Emory paper to put a brushed finish on the dash panel, the glove box cover and the audio mounting plate. Duplicolor makes a Metalcast enamel that is like Candy Apple Red, but simulates anodizing in appearance. After the brush surface prep, I used Duplicolor surface prep to remove any contaminants, then used their clear primer, followed by the red Metal Cast color coats, followed by a few coast of clear. After letting it sit for a week, I wet sanded the surfaces in preparation for the final heavy clear coat, which I applied after these photos. Good to be back in the shop.
The photos don't show it well, but it looks great next to the anodized stuff and the shift knob I already have in the interior. Thanks for the suggestions. I'll keep them in mind for the other surfaces I need to deal with.
The aluminum door sills are needing a surface. Anyone have any suggestions as to what might have some level of durability to it?
As to the aluminum door sills, I'd recommend a two-part zinc chromate or phosphate primer followed by a two-part polyurethane topcoat. Scuff sand the aluminum, phosphoric acid prep, rinse, and Alodine finish before priming. It is as good an aluminum finish as you are going to get. The US military uses this procedure.
The surface finish of the underlying aluminum & primer would determine its final finish- if it is smooth, you will get a nice, hard, glossy look. I've attached a photo of a rotor hub that I painted (with a brush!) as it is the only picture I have of a glossy polyurethane coating. It is an Eastwood two-part black coating.
The best stuff I've ever used was Chemglaze A made by the Lord Corporation years ago. It was a single-part polyurethane that cured from moisture (humidity) in the air. In the early seventies I painted it on a fabricated seat frame that I built for a Sabel sports racer and when I sold the car two years ago the paint was still hard and glossy blue, even after sitting outside in the Arizona sun for all that time. It was really good stuff but Lord replaced it with Chemglaze Z and they are totally uncooperative about selling it to individuals. Eastwoor or Aircraft Spruce are good bets for aliphatic isocyanate polyurethane coatings. Use a respirator or spray outdoors- or both!
If I use a clear enamel based primer, like I used with the dashboard to get the anodized look, will the urethane adhere to it and be compatible with it? I really would like to keep the brushed aluminum look, but not have to keep using steel wool on the surface. Back in the engine area, I can use the Balistrol (preservative oil) to reduce the oxidation, but that is not an option on the door sill. I can anodize the parts like I did the suspension, but looking at options.
Can I use the urethane over the anodized surface without primer?
Is there a more durable form of anodizing?
Sorry for all of the questions, but the door sills look great, and I don't want to screw them up.
Yes, you can use a polyurethane paint over an anodized coating (if it is absolutely clean) but an Alodine finish is just as good as a paint base and it is less expensive than anodizing.
There is a more durable form of anodizing, it is called "hard anodizing". It is used where abrasion resistance is important. Your choice of colors is minimal, though- gray or black.
Mark - my suspension pieces are hard anodized clear. My vendor could also do it in black but I was concerned with fading due to UV exposure; less of an issue for door sills.
The color you get is determined by the chemistry your vendor uses and the metallurgy of the aluminum being anodized. If you can get a small sample of the same material your sill was cut from that would tell you how your sills would turn out.
In my case my suspension has a gray, almost olive appearance to me. I’m pretty bad with colors though. I have photos in my build blog/thread but would be happy to forward you some higher resolution photos if it helps. Best thing to do would be to contact your anodizing vendor and have them throw a sample piece of your aluminum into their next batch so you can see for yourself.
My experience is with aluminum castings and machinings used in aerospace applications. I routinely used alodine, anodize, and other proprietary surface hardening processes.
We rated alodine a 0 for surface hardening capability. It was strictly used for its oxidation resistance properties. Anodizing (and the other processes we employed) were measureably superior for surface hardening. Subjectively, anodize is magnitudes superior to alodine for surface hardening. Alodine was only permitted in emergency repair type situations where it was impractical/impossible to anodize and the risk/probability of alodine failure was acceptable.
I’m not saying alodine doesn’t provide any surface improvement. However, given that anodize is a viable alternative and we’re not talking about a dimensionally critical component, there’s no reason to go down the path of alodine when the primary goal is to protect the surface from abrasion damage. I’d be inclined to do a type 2 anodize over alodine even. You’d get same or better surface protection and you can get whatever cool color you want if that’s what floats Mark’s boat.