Silver plating on tank coils

[va3dxv]

How best to clean up slightly corroded (not just tarnish) silver plating on tank coils? I have a B&W 850 that sat in a shed for too long. I thought about just using fine scotchbrite or something, and then electroplating it DIY style... but how much does it really matter with skin effect, efficiency, etc?

Thanks

[W7TFO]

Dunk the whole thing in industrial (not grocery store) Tarnex.

It will remove all the silver sulphide and leave what is left clean.

Rinse, dry, & relube the bearings and roller.

73DG

[KD6VXI]

As to how much it matters electrically, almost not at all.

--Shane
KD6VXI

[va3dxv]

As to how much it matters electrically, almost not at all.

So just run it as I brung it then? Works for me

Dunk the whole thong in industrial (not grocery store) Tarnex.

That would cost $300 and ruin a perfectly good thong.

Sure would like it to look shiny again though... I thought all those chemical things were gimmicks.

[W7TFO]

Caught myself in a tired, late night post.

Tarnex is legit.  Works.  Not very healthful, probably why it works.

73DG

[MikeKE0ZUinkcmo]

If you want to keep the "bright and shiny" I'd disassemble it and shoot it with some krylon clear.

[WD8BIL]

Dennis is right. Tarnex will work good but you must rinse it VERY VERY WELL!
Believe me, I know!

[KK4YY]

I'd be more concerned about the nut-and-bolt connections being corroded than I would about corrosion on the coil surfaces.

[WA2SQQ]

https://www.youtube.com/watch?v=9viOArsegIs

Watch this video. I used Buddy's recipe many times (12:35 on the video)

Cheap, easy and safe. Made up a large batch and cleaned may connectors I picked up at a local hamfest. They look brand new.
Let it soak and gently clean with an old tooth brush.

[KA0HCP]

Tarnish/corrosion on the coil isn't going to matter a whit until you are working perhaps high UHF into SHF.

Chemical removers like Tarnex work fine but don't do much to prevent future tarnish.  Polishing with gentle polish like silver polish or Simichrome smooths the surface pitting and reduces tarnishing.  However, the silver plating is certainly extremely thin and you are likely to wear through to the brass/copper. 

No need to do anything. Suit yourself as to cosmetic appearance.

[W7TFO]

One problem with roller inductors is they develop 'jumps' in the roller contact, which brings on arcing as they are adjusted.

It is hard to fix that if it is profound (like where you hear it).  The worn area can be built up in a labor-intensive process of soldering in new contact area, or dressing it down with a fine file if not too bad.  Pinching the roller tighter helps, too.

The better fix might be to add or subtract the capacitance in the circuit, to cause resonance to move off that spot and recalibrate the dial.

73DG

[w9jsw]

I don't see a roller.

[WBear2GCR]

https://www.youtube.com/watch?v=9viOArsegIs

Watch this video. I used Buddy's recipe many times (12:35 on the video)

Cheap, easy and safe. Made up a large batch and cleaned may connectors I picked up at a local hamfest. They look brand new.
Let it soak and gently clean with an old tooth brush.

Afaik, that is essentially an acid etch.
I would not recommend it for silver.
Tarnex has the benefit of not merely stripping the surface, but converting the sulphide.
Otoh, Tarnex smells awful...

                _-_-bear

[W7TFO]

I don't see a roller.

I didn't either, but most coils like it do.  Just info for the masses.

73DG

[WA2SQQ]

Several years ago I found some silver coins with my metal detector. I used Tarnax to clean one, just to test it. It definitely cleaned up the coin and but destroyed the value. Took it to a coin shop. The owner looked at it and said, you used Tarnax to clean it? It removed so mmuch of the finer detail. The Vinegar - salt solution is a lot weaker and much less destructive. Ive used it to clean old porcelain band switches without damaging them. If you dont mind rubbing, pick up some "Never-Dull". Walmart sells it in the auto department. Its a can of saturated gauze with a petroleum based cleaner. I use it to clean up chassis. Used it on my roller inductor where the silver was really tarnished. Looks like brand new.

[va3dxv]

https://www.youtube.com/watch?v=9viOArsegIs

Watch this video. I used Buddy's recipe many times (12:35 on the video)

Thanks for that. Been subbed to him for a long time but I must have missed/forgot this one.

I tried his method today on just the small 10m coil. It turned the shiny parts of the coil a much darker and more uniform black... but it did remove some corrosion and made the surface smoother. Unfortunately revealed some copper in the process but I kind of expected a little of that.

I tested in a tiny area, and it seems that if I used something abrasive it would shine up silver again. However the plating is too thin for that, so maybe the tarn-x would be worth a try, now that the rough corrosion is gone.

[WBear2GCR]

Once you remove silver, it's gone.

Imho, if the Tarnex "removed" the fine detail?
That's because the fine detail had already oxidized/sulfated off.
A second or two in Tarnex ought not remove much of anything.
If it takes longer, then the item is heavily "tarnished".

Neverdull is great for things like toggle switches: chrome or nickle plate. Solid copper too.

The silver plating on most radio stuff is very light and thin.

Even the pink paste silver cleaners are fine abrasives, remove too much silver on most RF parts.

The only good thing is that silver plating is actually relatively simple and cheap. Easy enough
to do in the sink. One can even plate "coin silver" which is silver with a high nickle content, harder
surface than fine silver. So, we can replate worn RF parts.

[KK4YY]

My guess is that you'd be hard-pressed to measure any difference in loss between a silver plated copper coil and an unplated copper coil at HF. On the air, you'd have to loose a few dB for it even to be noticed. I wouldn't loose sleep over it either way... but that's just me.

[WBear2GCR]

The difference is not there. It's the difference between silver oxide and silver sulphide vs. copper oxide and copper sulphide.

The latter two make for terrible electrical connections.
The silver oxide is virtually as good as clean silver.
The silver sulphide is not so great (it's the black stuff on silver) but still
better than the copper sulphide, afaik.

Also one wants to look out for electrolytic corrosion between dissimilar metals.

But short term, probably makes little or no difference - unless it does, then it will show
up as heat and/or a bad connection?

[KD6VXI]

VE7RF did a comprehensive test on this.

The coolamp style home plating doesn't give enough depth to even matter.

Most plating doesn't.  Unless your looking at frequencies a lot higher than most of us use.

You need multiple runs through a plating system to get anything that will matter at HF or MF.

Skin effect is a bish.

--Shane
KD6VXI

[kc2we]

If you do Tarnex, rinse with distilled water. You can get a gallon jug for about a buck each at the store. Tap water can leave a mineral residue.
ST

[N4LTA]

I built the Handbook 6 Meter amplifier quite a few years ago with a 4CX1000. It used the output coil made of copper tubing and it was compressed with a nylon threaded rod to tune the PI Net

I silvered it in the driveway with electro-plating using a silver 1 ounce ingot as the sacrificial anode  and a sodium cyanide solution. I did it outside because the process generated cyanide gas.

The plating was beautiful  - probably didn't improve the amplifier at all.  I bought a killogram of sodium cyanide which I still have. Anyone want it, I'll send it for free.

I bought the sodium cyanide from a well known supply house. At the same time, I bought a liter of fuming nitric acid. UPS delivered it in a small box with the two bottles packed in foam peanuts!!

You chemical guys know what could have happened it the box was dropped in a closed building!!!


Pat
N4LTA

[WBear2GCR]

Pat,

Email me the info on that chemical supply house that sold you the fuming nitric acid?
Need to remove the guts of a JFET, and that is the ONLY way...

                 _-_-

[N4LTA]

Sent