I noticed some corrosion on a few aluminum panels today. I'm able to remove it by scrubbing it with a scotch brite pad. Should I clean these up and have them powder coated or should I make new panels first? I'm concerned with the corrosion coming back.
Agree with Doug. The natural course for Aluminum exposed to air and moisture is to slowly oxidize. It does so immediately after any abrasive or chemical cleaning process, but the oxide layer is extremely thin. With time, the oxide layer becomes thicker. Because of various factors, this process does not occur totally evenly, as is the case with your panels. This is why architectural aluminum (as in door and window frames) are always anodized or powder-coated. For most of us, all things considered, powder-coating is the best route to go for the FFR body panels.
Here is a thread where filiform corrosion was discussed. What you have is not normal for our aluminum panels. On the other thread it ended up being swimming pool chemical storage causing the problem.
That looks exactly as mine do, although not to that extent. I have removed all my pool chemicals from the garage, but it still seems like the corrosion is continuing. I am still not totally convinced that the pool chemicals are the culprit.
I used a Scotch Brite pad (green) and removed the corrosion off of one small panel. It worked well, but will required a lot of work for all the panels.
I have not decided what I will do with the panels, as I really wanted the raw aluminum look in the engine bay. I do not feel the powder coating will give the same look.
If you don't get rid of the corrosion COMPLETELY, it will continue to be a problem.
When we have corrosion on airplanes, we have to make darn sure it's completely gone, even if this means taking major structural components apart to get to it.
Mike's thread he referenced above has lots of good info on corrosion.
Couldn't one simply paint over it with a spray bomb, (after careful masking, if on car) to stop the corrosion, and prevent future problems? Powder coating if the panels are already mounted seems like a major job, having to drill out rivets, cut through the silicone, etc..:sad:
Filiform corrosion can also be caused by electrolysis (electrolytic corrosion). I have filiform corrosion around the center of my aluminum Mazda 3 wheels due to the contact of dissimilar metals (steel hub against the aluminum wheel) along with high humidity (they get wet when it rains). In my case antisieze would have probably prevented it, but it's too late now.
Doug or other experts,
There are probably 1,000's of uncoated panels installed in these cars. Will this type of corrosion lead to something bad and if so over what time span?
Thanks
Arch
Arch, since this type of corrosion is pretty rare on unpainted, aluminum clad panels, I would think these particular panels were not treated properly from the manufacturer. Aluminum in this condition will normally oxidize, get that powdery white coating on them.
If left untreated, it will destroy the panels and eventually bleed over onto whatever material they happened to be attached to.
Untreated, they need some type of repetitive care, or just clear coat them if you like the aluminum panel look.
I was able to remove it with some scotch brite and elbow grease. My panels aren't riveted yet so I'll remove them and get them powder coated. Thanks for all the suggestions.
a follow up question: will "most" of the roadster panels simply oxidize in an even manner, providing its own weatherproofing coating? I ask because I am planning on a daily driver (yes, here in the northeast!) and would like to avoid the cost of powdercoating everything. Coast of a winter hardtop already increasing costs by a bit! If the panels really will need some protection to last, what about truck bed liner? TIA
Michael
I painted mine with a rattle can Hammertone paint. Came out really nice. Easy touch up and the aluminum is protected.
If you paint, scuff it up good, prime and paint. Best bang for the buck.
I just did the paint on my firewall and my F panels after they were in the car (not by me). It was a total PITA. There are just too many nooks and crannies to be able to mask everything easily and apply color (hammertone in my case).
What about cleaning them up THEN applying some sort of clear over them? You'd have to be less concerned with the overspray, and it would still look like it does now.
Another option that was (briefly) mentioned is anodization. I followed Larry Johnson's lead and had all of my panels clear anodized. Obviously, this would need to be done pre-installation, but it does give you protection from corrosion. If I'm gathering it right, SilverStreak has yet to install the panels, so it could still be done.
In the end, not a lot of aluminum is left showing (if you put carpet in), so asthetically, I didn't gain a whole bunch. But, they do look good. Engine bay stuff shows, trunk shows (unless you carpet it/sound proof it). Underneath shows when on a lift.
Just another option. And, I'm glad I did it at this point... ask me in a few years if my opinion is the same or not.
Be aware that you can't paint aluminum as if it was steel and have it last. Sheet aluminum is normally an alloy with pure aluminum clad to it. The pictures show filiform type corrosion IMHO. To be rid of it it must be mechanically removed, conversion treated with alodine, primed (preferably with zinc chromate) and painted. Powder coating or such of new uncorroded panels could work too.
Sharkhide is another option (after the panels are free of any corrosion of course). Much easier to apply than paint, and much cheaper than anodizing or clearcoating. Plus, it can be applied after the panels are on the car if needs be. I know "Greg M" and others have had good success with this route.
One of our vendors sell it, and the price is actually better than a couple other major suppliers: http://ffmetal.com/#sharkhide
I went to the powder coaters today and showed him the corrosion and oxidation on the panels. He said it would be fine after he treated it. I have to remove all the panels, file the edges and deburr the holes. I hope to have them ready for next week. He said he could have them done in 2-3 days and would be around $10 a panel. I've decided to do all of them after seeing the corrosion.
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