Chrome Pitting and Aluminum Spotting

[lonebird]

So I bought a vintage trailer and now the fun begins! The first decision I have to make is whether to restore or replace the original hardware. I would like to restore, but all of the chrome is flaking off of the original pieces. I called the local chrome shop and they said the parts were too small and the bumper was too big to chrome (aka they only want to do wheels.) What are my alternatives? Has anyone use POR-15 with the Stirling Silver top coat?



Next, on the back of my trailer is a plate of what I thought was Aluminum.



It looked dull


So I tried polishing it with Morther Mag's Aluminum Polish


And these black marks showed up. They aren't the polish, I tried buffing, and washing, even scratching with my finger nail. The black marks are there for good.

So what did I do?? why do the marks show up after the polish, am I taking off a protective coat?

And finally, The paint on our trailer is stripping off with a simple soap and water wash. We decided the plain aluminum looks great. How long do we have before we need to put a protective coat of sharkhide or nuvite on? We're in Monterey and it's been raining more then usual, I don't want to watch a 50 year old trailer rust away in the backyard...

Thanks!!!!

[48Rob]

Hi Bird,

Congratulations on your trailer!

The bumper wasn't chromed, just painted.
Many have had good luck with Por 15, most top coats should work over it.
Sandblasting and hammered metal paint would also look good.

The pitted chromed potmetal is tough, very expensive to rechrome if you can even find someone to do it.
May have better luck buying a used or NOS replacement on E bay, etc.


The back panel is aluminum.
There was no protective coating, other than the oxide (rust) that was helping to protect the metal.
What appears to be black marks are pits/corrosion that the polish has gotten into.
The pits may be able to be polished out, but you'll need power tools.
Use acetone or windex with vinegar to get the black residue out of them.

Nuvite isn't a protective coating, but a series of different grits of polish that can give the aluminum a chrome, or mirror look finish.

Aluminum oxidizes as soon as it is exposed to air, so after you polish or clean to the desired level, a coat of wax or other substance that will slow the oxidation process should be applied.
Be aware though, that even after applying a coating, any polished surfaces will need to be repolished in a year or so to maintain the original level.
Sharkhide may also work, but be careful of breathing the solvents, and or absorbing them through your skin.

Rob

[lonebird]

Wow, Thanks!

What sort of power tools? A Drill or automotive buffer?

Thanks again

[GreatPumpkin]

Wow, Thanks!

What sort of power tools? A Drill or automotive buffer?

Thanks again

Usually I'd suggest a 7" polisher to start (looks like an angle grinder, but larger). But your aluminum isn't smooth like an airstream. For what you have pictured, a drill with a buffing wheel would probably work best. You will also need Nuvite or other suitable polish (Try the Truckbox polish at Lowes, much cheaper). Lot's of elbow grease and time. Like Rob said, it's not a one time process. Aluminum starts to oxidize right away. Even after it's polished, it will start to oxidize right away. The good news is, it won't "rust" away. You can leave it bare and unpolished - it will simply turn or stay the dull gray you have pictured.

Pop over to the Airstream forum for lots of information on polishing - a particularly opinionated subject btw. http://www.airforums.com/forums/f441/

oops, forgot to mention - some aluminum alloy will NOT polish! From your first attempt with polish, I think yours will though. The black marks are probably as Rob says, just polish residue (it turns black when polishing) that has gotten into the pitting of the aluminum. Acetone, paint thinner, or multiple other solvents will clean it up. Also be careful about putting too much pressure on it with the power tools, or staying in one place too long - you can "burn" the aluminum. It will turn brown and that will NOT come out.

[DasBaldGuy]

I would suggest media blasting and powdercoating those parts. You can even have the Aluminum media blasted and then clear powdercoat to preserve it forever.

Most powercoating places have powders that are chrome-like and look really nice...or go with a silver or a black for contrast. Any color you can think of is available in Powder.

Powercoat is cheap and much stronger and protects much better than paint.

[atkryder]

When i worked at a tire shop we polished aluminum wheels with a electric buffer. We used a compound of jewelers rouge and lighter fluid mixed into a paste. I have yet to see anything work better. Not that expensive to make either.


Seth