Rain has run rust down the aluminum skin where the front-mounted spare tire carrier (like in my avatar) is mounted. I assume this can be polished off, but I worry about either removing the 37 year old clearcoat, or making it too shiny compared to the surrounding skin.
The carrier is off at the present for paint. Since I do not know if I will continue to keep the spare there (although the carrier will be there), I would like to address the rust.
Anyone have a product recommendation for removing rust from clearcoat?
Tom, I always use oxalic acid, available as crystals from a pharmacy. Also, stain removers for wood often consist of oxalic acid. It's used in the renovation of old wooden boats, for example. This link describes it: http://www.factsfacts.com/MyHomeRepair/RustStains.htm
I don't know if there is an adverse reaction with aluminium, so a test in a discreet place might be advisable. Good luck. Nick.
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Nick Crowhurst, Excella 25 1988, Dodge Ram 2500 Cummins Diesel. England in summer, USA in winter.
"The price of freedom is eternal maintenance."
Nick's post got me to thinking. But since I know nothing about chemistry, I stopped thinking, and spoke with one chemist, and emailed another concerning which chemical, Clorox or oxalic acid, was a better choice. The one I emailed replied:
Rust stains can be hard to get off. Plus other metals such as manganese could be present.
Clorox could corrode iron it comes into contact with. Chlorine from Clorox plus hydrogen from air or water can combine to produce hydrochloric acid, a strong inorganic acid (I believe they call it muriatic acid for use in swimming pools).
Oxalic acid is a weak organic acid. It could either precipitate the iron off as a ferric/ferrous oxalate or change the valence state of the deposit to a less visible form (which would re-oxidize over time to become visible again). If it doesn't work, or doesn't work well, I don't think there's a significant downside from trying oxalic acid.
The chemist I spoke with immediately preferred oxalic acid as he had once researched the issue concerning a work related situation. Offhand, he could not see the oxalic acid attacking either the clearcoat or the aluminum skin. But since it will be a slow process of continually wiping the area with solution, deleterious effects can be detected early, the cleaning stopped, and the area rinsed with water.
Ace Hardware sold me a pint of oxalic acid crystals (sold as Wood Bleach). The directions read, "Mix contents with one gallon of water". The chemist I spoke with thought this was a good strength to use.
I had planned to experiment this weekend, but am heading down to south Georgia for a family event. When I do get the chance to clean rust, I will take pictures. If it turns out well, I will post them. If it doesn't...well PM me if you really want to know.
Worked my rust issue this morning. Seemed like a great time to do it since it was cool, and kept looking like it was about to rain.
I mixed the oxalic acid according to directions, and kept wiping the area & rinsing my dishcloth for around 20 minutes. Some of the chunky rust was persuaded to let go with a blunt dental pick.
Here are two "after" pictures of the project: The first shows the area after the final rinse. The second shows the spare tire carrier loosely installed (just for the picture).
Good work Tom.
I was afraid the ACLU was going to get you for displaying a cross on your A/S!!! Better get the tire back on!
I used to use oxalic acid for bleaching black stains out of oak. It's been used for centuries to remove blood stains from garments. (factoid of the day)
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Murray
AIR #189
"If aluminum isn't magnetic- why am I so attracted to to it?"
Tom, this is an excellent result. However,if you ever considered becoming a Druid, your original burning red cross was more appropriate! Nick.
__________________
Nick Crowhurst, Excella 25 1988, Dodge Ram 2500 Cummins Diesel. England in summer, USA in winter.
"The price of freedom is eternal maintenance."
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