How to remove rust from iridited aluminum chassis?

[Gregory]

I may be getting stiffed with a piece of B&K gear from sl'e(z)bay that was described as `like new´ but substantially covered with rust and corrosion. Cover must be scrubbed and repainted.. but WHAT is the BEST way to dissolve white and green corrosion from a iridited (yellowish) chassis?

Also looking for some 4-48(?) `fine´ thread screws to replace rusted and corroded hardware.


-Gregory

p.s. anyone get stiffed with misrepresented items like this?

[bricktop]

Also looking for some 4-40x48(?) `fine´ thread screws to replace rusted and corroded hardware.

Check Mcmaster-Carr: www.mcmaster.com

They have every nut and bolt imaginable

[Mark W.]

The fine screws can be found at McMaster-Carr along with taps and dies to match You might also find them at a local Hobby shop but I doubt the 4-48 the 4-40 yes

[Gregory]

Check Mcmaster-Carr: www.mcmaster.com

They have every nut and bolt imaginable

Thanks.. we buy a lot from McMaster Carr at work. Do they sell to just anyone?

-Gregory

[Gregory]

The fine screws can be found at McMaster-Carr along with taps and dies to match You might also find them at a local Hobby shop but I doubt the 4-48 the 4-40 yes

Wish I could determine the exact thread. It's 0.115 Dia and definitely finer that 4-40. What are the only other machine screws that are .115?

Maybe I'll order stainless since McMaster has lots of that stuff too.

-Gregory

[bricktop]

Yup I make small orders all the time. They have online ordering which makes it easy. I also found out about them through where I used to work. They ship super fast too.

[Tom Bavis]

3 mm is finer pitch than 4-40, slightly larger - commonly used for the smaller screws in PCs. I can send you all you'd like - what head type?

[Paul C]

Check your local hobby shop for 3 mm screws. Ask for the Dubro hardware for R/C cars. You will find all sorts of Philips and Allen head cap screws, various lengths.

[Aage]

For the rust, you might want to try a bit of Naval Jelly in a discreet spot. It works well on rusty steel, but I've no idea of it's possible effect on aluminum.

[Switchblade]

How do you get "rusty" aluminum? What do you mean by "iridited"? If you mean irridescent, there is a spray aluminum cleaner and also bottled cleaner for aluminum available in most hardware stores. Very acidic, but makes it VERY clean. Many name brands, just ask the hardware guy.

[Gregory]

How do you get "rusty" aluminum? What do you mean by "iridited"? If you mean irridescent, there is a spray aluminum cleaner and also bottled cleaner for aluminum available in most hardware stores. Very acidic, but makes it VERY clean. Many name brands, just ask the hardware guy.

I'm not sure what the chassis is now, but it's a yellowish metal. Iridite is a chemical that aluminum parts are dipped in, giving them a yellow hue.

The chassis has white-powder type corrosion on the outside, however it has rust on the inside `floor´ of the chassis. ebay seller described as `like new´ and if they get away with misrepresenting junk like that as LIKE NEW then ebay isn't the place for ol' Uncle Greg. :)

So the chassis is a yellow color and has both white corrosion and rust on the inside. Maybe it's steel and the coating turns white, and finally in advanced stage of oxidation, base metal rusts.

Quote: Iridite is a brand name for chromate-producing product that belongs to MacDermid Inc. Iridite 14-2 is on QPL-81706 for producing both Class 1A & Class 3 chromate coatings on aluminum. Alodine 1200S is a similar product from Henkel.

-Gregory

[Gregory]

3 mm is finer pitch than 4-40, slightly larger - commonly used for the smaller screws in PCs. I can send you all you'd like - what head type?

I'll use calipers on the screw(s) at work today. The 4-40 screws did measure slightly smaller in diameter. The head type is philips. Must also measure the length so hold off a bit. :)

-Gregory

[SaSi]

Most of the steel plate chasis I've seen are yellowish. They actually have a yellow/green color depending on the angle of light and angle of view.

Don't know how they are treated to show like that, but my guess is that the treatment and resulting color are designed to protect against rust.

Aluminum, against common knowledge that doesn't get rusty, CAN get rusty. It's just damn hard for it to rust, and would require severe humidity along with corosive atmosphere. Don't get me wrong, I don't mean to imply that your hardware was stored in a volcano. Even traces of soldering putty left on an aluminum panel for a few years will cause corosion.

And, aluminum oxide (Al2O3) is whitish and turns aluminum into powder. Get lot's of that powder, mix them with gelly and you have alumina cutting cream, but that's a different story.

The problem with corroded panels is difficult, since any attempt to remove corrosion will remove the (possible) lacquer finish and also remove parts of the panel surface. Get's worse if there is lettering on the panel. How can that be replaced?

Now, if we forget about the lettering, the best way to treat a visible aluminum panel and restore it to perfect looks and satin touch is to use alumina cutting cream. It can be effective even if applied with a moderate size piece of cotton or a cotton cloth. My old worn out panties are my favourite "tool" for that...

If the panel is brushed, you should scrub it in the same direction so that the brushing effect isn't lost. If you want, though, you could totaly remove the brushing effect by scrubing at 90 degrees to the brush stroke, and with a lot more work the panel can get a silk like at touch.

I have a Revox PR99MkII that I am restoring and the bottom panel has this kind of corrosion (very little, though) in some small area. I would like to repair that, but all the lettering on the panel would get destroyed. Don't know how to redo them.

[Switchblade]

Aluminum CANNOT rust. Rust is a combo of iron and oxygen. No iron, no rust. Aluminum oxidizes, a combo of aluminum and oxygen hence the white powdery finish. Same for magnesium, only worse.

[fcarpcarp]

Possibly it's zinc on steel with a yellow chromate coating.
http://en.wikipedia.org/wiki/Chromate_conversion_coating

They are common on elect. chassis, springs, and fasteners.

I would contact a local metal plating shop and pick their brain.

fcc

[toxcrusadr]

It could be a cadmium plating which makes yellowish green powder when it corrodes, but I doubt the piece is old enough for that. Old radios often had Cd plating on the chassis. I'd go for yellow zinc like the deck screws you find at the hardware store.