Chassis Cleaning

[Clean&Tight]

I was fortunate and got a nice one with no rust
Cleaned up well with mild water and ammonia solution as suggested here
Overall has a decent patina, still a little "milky" in spots like they all seem to be but very minor and just sort of "flat". Some shine but not much.

Last night, just for the heck of it, I gave an area a go with a little Nevr-Dull to see if it would take out those white spots. It pulls crap off the metal so well it turns BLACK (the piece of wadding, NOT the Fisher ) same as polishing brass with Maas of Flitz. When I buffed the area with a clean micro-fiber rag it too came up black.

After a few passes the steel begins to reflect light and the image is fairly sharp. It will never polish out to a point like a chromed Mac, but it's pretty doggone shiny.

My question is, am I causing a long term problem? Does anyone know for a fact if this steel is galvanized or what the coating is? Nevr-Dull is pretty mild, what little mechanical abrasion it has is in the soft wadding. I've seen the chassis that look fantastic after having been gone over with Maas or Flitz but I know from experience that they do remove a very small amount of material.

I have one tiny little rust speck on this entire chassis. I don't feel as if I am scrubbing away any anti-corrosive topcoat using Nevr-Dull (judging from that one spot) but I don't know for sure. It's not like lacquer; Nevr-Dull will remove that if you're persistent! That extra level of shine is nice but not worth causing harm. I would only do the large areas anyway; leave the lettered sections alone.

I did do my tuning cap cover and tube shields with Flitz. They look great, like stainless now. But the rag was still coming up black when I finally said "enough!". I finished those off with a little car paste wax after polishing.

What do you think? Overkill? Am I removing the galvanization? Or is it even galvanized? You know how the interior sections still have quite the shine and there are areas of these old chassis that would lead you to believe that when new, they did in fact "shine" quite a bit.

What gives me pause are things like that tuning cap cover and the ventilated cover for the speaker select switch. Their dull flat patina is just that, but homogeneous and smooth which would make me think they were that way from day one, but they are also obviously from a different stock and gauge of metal.

I'm definitely up for doing the sides until they gleam, but don't want to screw things up. One of those easier to do than undo choices.

Thomas

 

[drewbolce]

Just be sure to finish the chassis with a good coat of a high content Carnuba car wax. If you leave it as is it will tarnish quickly. That black on your cleaning cloth was a layer of cadmium oxide which was serving as a protective coating.

The rule here is don't use metal polish unless you intend to wax it. The use of ammonia alone will leave the oxide layer and can be left without waxing.

I like to go the whole way myself. I use janitorial strength ammonia followed by MASS or Weenal (same stuff) and finish with good car wax.

I use the high strength ammonia since these units are from the smoking age (not them, there owners). Nothing but ammonia will remove the dust and smoke tar glue that typically coats them.

 

[Clean&Tight]

Just be sure to finish the chassis with a good coat of a high content Carnuba car wax. If you leave it as is it will tarnish quickly. That black on your cleaning cloth was a layer of cadmium oxide which was serving as a protective coating.

The rule here is don't use metal polish unless you intend to wax it. The use of ammonia alone will leave the oxide layer and can be left without waxing.

I like to go the whole way myself. I use janitorial strength ammonia followed by MASS or Weenal (same stuff) and finish with good car wax.

I use the high strength ammonia since these units are from the smoking age (not them, there owners). Nothing but ammonia will remove the dust and smoke tar glue that typically coats them.

Hi Drew,
Cadmium oxide is used in electroplating for corrosion prevention, but I don't think it's on the metal in it's raw form?
I always thought that cadmium oxide was that nasty whitish powder that forms on the surface of really old speaker baskets and the like that you DID NOT want to breath when cleaning or handling.
I'm not arguing with your statement in any way, I just understand it (poorly) that the chemical cadmium oxide is part of the process, not the final finish. In it's raw form it's usually brown in color and a powder. Airborne it's pretty nasty stuff.
I've done some research and learned that during WWII tools were cadmium plated due to shortages of nickel and chrome. From reading on those topics (old tool collectors) you can mechanically remove the stuff, but you can't wash or polish it off. Polishing of course within reason, not sandpaper or a wire wheel!
http://periodictable.com/Elements/048/index.html
I agree with you and always follow up on cleaned metal with wax anyway. I just wish I knew for certain that Nevr-Dull wasn't screwing something up. In and of itself it's pretty gentle compared to Flitz and even Maas, anything containing an abrasive. Even something as fine as rotten stone.
For what it's worth, Flitz, Maas and even Nevr-Dull will keep making a rag black forever it feels like. Even when I'm polishing brass and it's so shiny it's blinding me!
So tempting to polish out this chassis :yes: but I don't want to wake up one day down the road to rust or some new issue.

Thomas

 

[drewbolce]

The Fishers were Cadmium plated and then passivated, as a result an oxide layer will form. The shiny stainless steel we are used to seeing is passivated also. The top layer is Chromium oxide which is where the resistance to rusting comes from. There are generally several oxides of any metal. In this case we are talking about the +2 oxide, a very corrosion resistant oxide which is also clear. BTW, this is how rust "converter" solutions work, they chemically change the iron oxide (rust) to a more stable form.

Cadmium is an accumulative poison. Wash your hands and don't lick the rags.

 

[Clean&Tight]

The Fishers were Cadmium plated and then passivated, as a result an oxide layer will form. The shiny stainless steel we are used to seeing is passivated also. The top layer is Chromium oxide which is where the resistance to rusting comes from. There are generally several oxides of any metal. In this case we are talking about the +2 oxide, a very corrosion resistant oxide which is also clear. BTW, this is how rust "converter" solutions work, they chemically change the iron oxide (rust) to a more stable form.

Cadmium is an accumulative poison. Wash your hands and don't lick the rags.

Understood. In your opinion do you think that Nevr-Dull, NOT an abrasive product like Maas, is actually removing the protection or simply cleaning it to it's former sheen?
Just a wet rag alone will remove an amazing amount of haze.
I'd love to see a good photograph of one of these chassis when it was brand new, then I'd feel better about going forward or just leaving things "as is".

Thanks again,
Thomas

 

[Clean&Tight]

The Fishers were Cadmium plated and then passivated, as a result an oxide layer will form. The shiny stainless steel we are used to seeing is passivated also. The top layer is Chromium oxide which is where the resistance to rusting comes from. There are generally several oxides of any metal. In this case we are talking about the +2 oxide, a very corrosion resistant oxide which is also clear. BTW, this is how rust "converter" solutions work, they chemically change the iron oxide (rust) to a more stable form.

Cadmium is an accumulative poison. Wash your hands and don't lick the rags.

As I understand it, passivization can also be a spontaneous affair, most commonly resulting in the white surface we all know too well.

That's the one I want to get rid of! But only if it's of the spontaneous variety!

 

[audiodon]

I like cabinets. I used to be a lot more particular about how the chassis would look, but ultimately I realized that most every tuner, integrated amp or receiver designed after 1960 (with the exception of a few like the SA-1000) were designed to be in cabinets.

 

[Clean&Tight]

I like cabinets. I used to be a lot more particular about how the chassis would look, but ultimately I realized that most every tuner, integrated amp or receiver designed after 1960 (with the exception of a few like the SA-1000) were designed to be in cabinets.

Mine's going back into it's box soon enough. Will probably run it out in the open for another few weeks of the shakedown cruise. Little touch ups, cleaning missed spots, all the little final details. I'm hoping that once it's back in the box it'll stay there for maybe another 40 years or so, as like new as possible. All the dust and dirt from this point forward will be all mine.
Just figure that while I'm at it I want to do as good a job as possible preserving it's condition without doing harm.

When it just keeps getting better and better it's hard to stop, or maybe knowing when to stop! :yes:

Thomas

 

[larryderouin]

That's the problem. Realizing when to stop tweaking and enjoying it. I guess it's part of the "fun" of restoring them. As never dull is non abrasive, all it's doing, like Drew said is breaking down the surface dirt, and allowing it to be removed. I find it does as good a job as Brasso, but it takes more elbow grease. Much as I'd like to be able to shave by the reflection of the moon on one, I put a limit as to how much dis-assembly I will put up with. As long as i can get in the little nooks and crannies(or crooks and nannies) with a toothbrush, I'm fine. It's clean, it shines (better than it was) and it works. Now is the time to reap the fruit of your labor.


AW CRAP.......Where the hell is the Church Key. (No self respecting Barley pop would have a twist off cap).

Larry

 

[2string1]

How about some pics?

 

[drewbolce]

Understood. In your opinion do you think that Nevr-Dull, NOT an abrasive product like Maas, is actually removing the protection or simply cleaning it to it's former sheen?
Just a wet rag alone will remove an amazing amount of haze.
I'd love to see a good photograph of one of these chassis when it was brand new, then I'd feel better about going forward or just leaving things "as is".

Thanks again,
Thomas

What I was referring to is a chemical reaction. The light abrasive action of the polishes can be ignored unless you are too aggressive on the lettering.

If you see black in the cloth then the cleaner you are using is lifting the protective layer, its as simple as that.

Did the ammonia leave the black residue? It will not because it does not react with layer.

 

[drewbolce]

As I understand it, passivization can also be a spontaneous affair, most commonly resulting in the white surface we all know too well.

That's the one I want to get rid of! But only if it's of the spontaneous variety!

Passivisation is a chemical process that removes contamination and undesired metals. The goal is too leave a clean continuous layer of the desired metal which will then form the desired oxide.

Oxidation is a spontaneous affair. My research into this started when I made the erroneous claim that Titanium doesn't oxidize. I found out that this is wrong, Titanium forms a thin, clear and indestructible oxide without any treatment.

 

[acoleman]

Black marks? Oxidation or corrosion

It's not "dirt" and it's not a white power on my Fisher 500C chassis. it's all over the top, around the tubes, etc.

I tried a few metal cleaners, cloth, fine steel wool, etc., and the black dots and marks are still there.

Is there a chemical that will clean it off?

Thanks!

 

[mibag6]

The black dots and marks are probably rust pitting the chassis. Difficult to remove after a point without removing the surrounding plating nearby. I had a couple of fairly good sized spots which I polished down to bare metal with a Dremel wire brush followed by polishing compound and it looked better than the black spots but not like new. Then, I waxed over the spots to slow down future oxidation but I don't know that I'd do it again, it's a lot of work for minimal benefit and of course
the steel is a different color than the cadmium so there's still discoloration just not quite as noticeable. Put up some pics so we can see exactly what you have to deal with.

 

[Westy56]

I'd love to see a good photograph of one of these chassis when it was brand new, then I'd feel better about going forward or just leaving things "as is".

Thanks again,
Thomas

If you're diligent and wipe the black stuff up frequently as you clean, the results are worth it. :thmbsp:

This is what never dull did for me. It was a total pain. :sigh:

 

[audiodon]

This thread inspired me to create a chassis cleaning thread that has now become a sticky.
I hope you find it useful.
http://www.audiokarma.org/forums/showthread.php?t=406997

 

[1924 popcorn]

Ill be doing some cleaning on this. Hope all go's well. It has to be done so I'm reading all I can to get it right