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re-plating tube shields?

gadget73

gadget73

junk junkie
Subscriber
Anyone ever re-plate steel tube shields? I've got some that are the usual grey-brown color with faint evidence of some sort of plating that has long since been cooked away. I've got the stuff around to do nickel plating, thinking that ought to spruce them up.

The real question is what were they plated with originally? I'm guessing zinc.
 
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Maybe they're not all the same, but I always thought the standard shields made by EBY, Cinch, etc. were nickel. Some might be brass rather than steel. I'm going to check a few of mine with a magnet later, just to check. Sometimes these can be buffed. The original plating is really thin though, and it's easy to go through.

Jack
 
It turns out that some of mine are magnetic, others not. They are also different weights, and a few are so light, they're obviously aluminum. Regarding the non-aluminum shields, those that aren't magnetic seem to have weathered better over the years, more chrome-like. I think they're nickel-plated brass. The two I'm using for my current preamp project are magnetic. I buffed them some time ago, but they never got really shiny, just a dull silver color. I think they're nickel-plated steel. None of mine have the characteristic yellow corrosion of zinc, but I have seen that on some shields in the past. I think the bottom line is that vintage tube shields have been made from everything except plastic.

Jack
 
gadget73 said:
Anyone ever re-plate steel tube shields? I've got some that are the usual grey-brown color with faint evidence of some sort of plating that has long since been cooked away. I've got the stuff around to do nickel plating, thinking that ought to spruce them up.

The real question is what were they plated with originally? I'm guessing zinc.
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Not sure what style you have, but here are pictures of my tube shields from my HK a50K integrated amplifier. I found some parts in my tool box to be able to attach the shield to my drill and used 0000 steel wool to buff them up. I think they came out really nice!
 

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These are definitely magnetic. I've had aluminum ones, not sure about brass but possibly. I have a few styles that were steel and equally crappy looking.

There is slight plating still on the inside. Only reason i ask about the original plating, if its zinc i have to strip it because nickel won't plate over it.
 
Not yellow, so i don't think its cadmium

Zinc is what i figured. Ill just acid dip them until it goes away. Needs acid to get rid of the dark oxidation anyway
 
Not all Cad is yellow. I used to get my British fasteners re-plated by a local aviation company as Type 1, which gives the silver-colored finish.

Cadmium Plated Finishes | Electro Loh, Montreal Electroplaters

Electro Loh offers cadmium plating services. Cadmium, excellent corrosion resistance, May be dyed to many colors, Has attractive final finish, Good lubricity and solder ability characteristics, An attractive final finish and is good paint base.
www.electroloh.com www.electroloh.com
 
This got me to wondering. Only going by a vintage Fisher pre-amp and tuner that I own and assuming they represent the era. As expected, shields are magnetic.
My undestanding is: chassis are cad plated. Tube shields are zinc.
 
Steel shields will be better for keeping 60 cycle hum out and radio signals out, just better shielding. Aluminum is not very good.
 
gadget73 said:
Not yellow, so i don't think its cadmium

Zinc is what i figured. Ill just acid dip them until it goes away. Needs acid to get rid of the dark oxidation anyway
Click to expand...
Funny, I just got some supplies to zinc plate some old Hot Wheels cars. They're made of ZAMAC (Zinc Aluminum Magnesium and Copper) and can discolor.

20241011_173750.jpg
 
gadget73 said:
Anyone ever re-plate steel tube shields? I've got some that are the usual grey-brown color with faint evidence of some sort of plating that has long since been cooked away. I've got the stuff around to do nickel plating, thinking that ought to spruce them up.

The real question is what were they plated with originally? I'm guessing zinc.
Click to expand...

Gadget,
I just scored a Sherwood S8000 /7868 with a beautiful copper plated steel chassis.
Only problem is it has NO tubes and NO shields...so I'm looking for shields (and tubes except 7868's).
These are unique to Sherwood's so kind of hard to find.
Also, they cost about the same as the tube they shield.

I found six so far, but they a not worthy of populating this pristine chassis.
So, I'm thinking of plating the (steel) shields. They look to be nickel plated, but show 60yrs age.
I have a bottle of old GOLD plating solution. Or maybe nickel or copper?
How nuts would that be?? how did it go?
anybody?
 
Ah yeah the Sherwood teepee shaped shields.

So i did nickel plate one, and it came out ok. I think maybe i should have copper plated it first. Might try another when i feel bored, just have so many other nagging things to ignore that i haven't gotten to it.

I think straight copper would look nice in a Sherwood with a copper chassis. My s7000 is copper.
 
S7000's are unique in their own right.
ignore, heh heh, I get that. I just finished painting a whole house -I'm tired, but gearing up for winter projects.
Copper would probably be more of a fit. Debating to use a plate brush or dip...

Here's a more global question, I have another copper plate chassis that looks like it had a whole can of soda pop spilled into it -so it has rusted thru plating spots with that odd green sulphide surround. Looks more like a rusty hulk steam punk than a receiver. I could POR-15 treat it but it's not a rusted out old Porsche 356 hardware so not really the right thing to do in this case. Maybe I should just leave it alone, bring it back to life and emphasize it IS a steampunk hot tube 1962 rocker.
k
 
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