Cleaning Aluminum Frames

[Wagner]

My LE14As have some dark, heavy spotting and staining on the grained face of the frames (mounting flange). One much worse than the other.
It is the typical old age spotting like what occurs on 044s but in this case it is pretty extreme.
I have made some progress with the usual suspects; Brasso, Flitz and Nevr-Dull but I still haven't managed to get rid of it all, yet. They are almost tolerable but it would be nice to get it all.
I'm almost beginning to think that this discoloration is coming from the INSIDE, out.
Steel wool's out of the question and I don't want to foul up my nice white cones.
Any ideas or product suggestions?
Thanks,
Thomas

[Baron030]

Hi Wagner

In a way aluminum does have a porous surface. So, your observation about the off-color coming from the inside is not so far fetched. What I would recommend is a phosphoric acid based cleaner. I have used ALUMIPREP 33 and it cleans aluminum like nothing else I have ever seen. Here is a link describing the product:

http://www.awlgrip.com/Product%20Datasheets/4093+A+eng+A4.pdf


Unfortunately, the smallest amount that you can order is a quart and it should be diluted with 5 parts water. So, unless you have a lot of aluminum to clean, one quart is a lifetime supply. Alternatively, you could try another phosphoric acid based cleaner. “CLR” is a readily available bathroom cleaner and it does contain a mild phosphoric acid solution. So, you could give that a try.


Baron030

[grumpy]

A few thoughts...

Perhaps experiment on a less dear driver... say a toasted LE5-9
where no replacement kit exists.

That said, be -really- careful, or dilute significantly... specifically says -not- to
be used on aluminum castings (presumably due to porosity and the
continued, uncontrolled etching that may result without a de-ionized
water bath to flush the etchant).

If this is the finish I'm thinking of (essentially brushed aluminum),
you might consider spray/glue-ing a few sheets of sandpaper to a
big piece of glass or verified-flat chunk of MDF ... move one
direction only and abrade the discoloration. Follow up with a
clear-coat finish if desired.

[cooky1257]

I had some success with wire wool and pan scourer-the soapy kind.

[Tim Rinkerman]

If you are talking about the thin exposed edge of the casting,outside and lower than the edge of the gasket..400 grit wet/dry sandpaper..dry..fold it up and carefully pull it around the edge, square on the edge. Stay off the gasket, and don't roll onto the painted surface. Turn the paper often, so you are always cutting with a fresh surface. Don't just polish out the stained area, do the whole edge, it will look factory!