72 TA : New Project

[DaJudge]

As usual awesome work Steve. Happy New Year !!

[njsteve]

I have been wondering what to do about the scratched up anodized aluminum window trim on the front and back windows. I figured I have no problem with polishing them if I could get the old scratched anodized finish off somehow. So, I did a little searching and found the following method worked pretty well. It seems that using Sodium Hydroxide (common household powdered lye/drain cleaner) is what most people recommend. I also stumbled across something that worked much better for the initial heavy stripping...what is it? Why the same old "Purple Stuff" of course! I happened to place a couple of trim pieces in the Purple Stuff just to clean them off and after a few minutes the anodizing started crusting up and bubbling off. So, I did what most people would then do: I read the ingredients on the Purple Stuff jug and low and behold it contains Sodium Hydroxide. It must be in some heavy concentration becuase it worked much faster than lye mixed in water.

Here is what I set up to do the larger pieces: a kiddy pool lined with heavy 6-ply plastic sheeting from Home Depot. I filled it with about 8 gallons of water and then added one can of powdered Drano. It takes about 2 hours before any progress is observed.

[njsteve]

It does take time and you have to continually check on the progress so you dont get to the point where the anodizing is gone and your aluminum trim starts feeding the chemical reaction instead. Here is the trim after about 5 hours. You can see the tiny foaming bubbles rising from the trim pieces.



Here is what the piece looked like at the 8-hour mark. You can see most of the anodizing is gone except in the corner area, whcih was the slowest area to dissolve.

[njsteve]

After seeing what the Purple Stuff did I set up a plastic pipe capped at the bottom and filled with the Purple Stuff. I then hung the straight price of trim on a wire and hung it in the pipe.



Here it is after 30 minutes:



And after 2 hours:



You need to check this solution frequently and use a Scotch Brite pad or 0000 stainless steel wool to scrape the anodized crust off of the surface. This allows the chemical to get a better bite at the surface and continue the process. The Purple Stuff does work very well and very rapidly but seems to reach a point of diminishing returns after a few hours.

[njsteve]

The reason I used the Purple Stuff and tube method on the long piece was simply, that it was too long to fully submerge in the kiddy pool. You have to have the entire piece submerged otherwise you get uneven stripping and a big parting line in the trim piece.

Once the Purple Stuff did its work I then washed it in cold water and then transfered the straight trim piece to a section of plastic gutter lined with the same 6-ply plastic sheeting. I filled it with some of the same lye and water solution from the kiddy pool. You can see that the 2 chemical method (Purple Stuff followed by lye/water) works well as the lye solution immediately started taking away the remaining anodizing.

[njsteve]

From start to finish it took 12 hours of soaking in the lye solution to remove all of the anodizing. This included the periodic removal of the trim from the solution, the scrubbing of the surface and washing with cold water and then replacing in the solution again. I think if you used a higher concentration than one can per 10 gallons of cold water you would get faster results. One website I found suggested 1/2 cup per gallon of cold water. But since I was trying not to poison everyone in the house I decided to do the conservative method. When I was done, I poured the drain cleaner solution down the slowest sink drain in the house, which cleaned that up a bit as well. As for the trim pieces, I placed them in the shower and hosed them down with cold water for 5 minutes or so to get all the residue off.

One additional thing to remember. You must use proper protection: heavy rubber gloves and safety glasses are a minimum, plus proper ventilation.

Here is the before on the corner piece:



Here is the after:



And here are the other pieces, all ready for polishing this weekend.






This was a cautionary reminder I found on one website concerning using this method:

"Fast and easy, maybe. Dangerous, absolutely. Just one more reminder that every year trained professionals wearing protective gear are seriously injured when something goes wrong making up solutions of sodium hydroxide. It has an enormous "heat of solution" / "heat of dilution". This means when sodium hydroxide is mixed with water, it heats up the water. Not a big problem if a small amount is well mixed into a large amount of cold water. But if a small amount of water mixes with a large amount of sodium hydroxide (which can happen even in a large tank with poor mixing), that small amount of water is instantaneously turned into steam and erupts the contents of the tank all over the operator."

http://www.finishing.com/3600-3799/3674.shtml

[Verne_Frantz]

Steve,
Based on your last precautionary statement, I will add the "rule of thumb" for mixing caustics or acids with water. ALWAYS, add the caustic or acid to the water, never the reverse. IF the water is already there when the chemical is added, it will instantly be diluted and will not result in a violent reaction (erruption). Water first; chemical second.
Even when cleaning your home drains, never pour the chemical in a dry drain, then add water. ALWAYS run water first, then add the chemical.
Verne

[Judges4u]

Steve,

Excellent info on restoration techniques. Your car will be awesome when done.

Have you tried any cadmium replating do it your self products from the following company?

http://www.caswellplating.com/kits/copycad.htm#

This company has several kits to replicate the cadmium (yellow irridite) process.

Thanks, Jim

[njsteve]

The body is finally at the body shop. I dropped it off last Saturday. He started on the paint and bondo removal to see what was underneath. I think we will now retitle this thread: "The Return of the Bonnie and Clyde Car." Take a look at the dent puller/bondo worm holes. I lost count at 167 on the driver's quarter.

Looks like she's gonna need a bunch of hours of metal massaging. No panel replacement plans since it is so rust free, just a whole lotta torch, hammer and dolly work in the future.



Or we could call it the "Lite Brite Special."



The view from the door jamb vent: