Many thanks to SWLing Post contributor, Mark Hirst, who writes:
Going to a local UK charity shop will usually turn up a grim selection of romance novels, old DVD box sets and children’s toys. They do a brisk trade in clothing, shoes and bags, but technology often consists of dire examples of cheap DVD players, phone cases, and small TVs.
It’s those very occasional gems that keep me going back.
Last Sunday a Panasonic radio turned up, and being a canny eBay savvy charity, they put a proper price tag on it! Aside from a scratchy volume control which was easily sorted, it seems to work fine. Spanning the whole of shortwave on a single band selection makes for tricky use of the big tuning knob, but back in the eighties I suspect this wasn’t a problem.
Finger marks and general grime have cleaned up fine, but the handle is strangely marked, and after fruitless cleaning with cotton pads and a little water I’m wondering if this is some kind of oxidation below the shiny surface.
I’m wondering if other readers are familiar with this kind of problem?
What a great score at the thrift store, Mark! I have several receivers of the same era that have the same issue on their chrome/metal parts. It’s almost as if the chrome/metallic finish is pitted in some way.
Readers: Do you know how Mark could safely clean the marks off of the chrome finish on the handle of his RF-1405?
FYI, here’s a video of Mark’s RF-1405 tuned to CRI:
Mark, you certainly snagged a great radio at the thrift store!
There are two products that come to mind, Flitz and Nevrdull, both name brands. Everything Paul Evans said is true, I’m simply mentioning these products as two I have used on plated metal products in the industries I have worked in. For the most part, if the products appear to be working it is because they have removed the surface, visible corrosion. That does not mean the corrosion has stopped. A coat of wax of some sort can slow the re-occurrence of the corrosion IF caused by environment conditions. If the cause
is withing the metal itself (instability, contamination of the substrate etc.) then nothing can help. Can the metal be re-plated? Anything can be done if you want to spend the money.
Having been the device manager for a large semiconductor manufacturer I can tell you that you won’t fix this, you’ll make it worse. Chromium is the worst metal for stacking faults. That means that preparation of the base surface before metalisation is VITAL. If any contamination or defect exists on the base material it will be transmitted up through the chrome plating. That’s why chromed morse keys vary from one to the next (you can often see finger prints showing through in the plating!). Steel plated with chrome is the worst because moisture gets down the stacking fault and rusting occurs, eventually opening out to a ghastly appearance. To give you my worst case, in which chrome was forced upon me in a certain device, the problems were only eliminated by five washes in 18 Mohm water, surface cleaning with three different solvents, five more washes in 18 Mohm water, instant transferal to the vacuum chamber of the metalisation sputterer, 30 minutes of RF assisted oxygen sputter cleaning, finally about 2500 angstroms of metal deposition. I wanted to be rid of the chrome completely, but the device had already been life qualified and it would have meant re-testing from a very expensive beginning.
Chrome is horrible stuff and it’s why the car industry was very glad to be rid of those huge rusty bumpers / fenders! Anybody working in chrome plating will tell you CLEANLINESS IS GODLINESS. Panasonic contracted this to a part manufacturer who was either sloppy or having a bad day or even a bad operator.
A quick search of the Antique Radio Forums website turned up very little except to try
white vinegar.
There are some auto polishes and cleaners that claim to do this but be careful.