White Oxide On Old Equipment

[corgan4321]

Hello,

I’ve opened up a Hickock Tube Tester Model 752A that has quite a bit of white powdery oxide (?) f some kind on some of the parts. A lot of the brackets, screws, rheostat, etc show a build up of the stuff. I’ve read mention that it could be cadmium sulfide or oxide and is toxic. Can anyone verify what this gunk is, and perhaps offer some help whether the unit will still be serviceable? Worth restoring? Some of the contacts on the tube sockets show evidence of the white build up, while others are clean.

 

[Tubetec]

Did the unit live in close proximity to the sea , salt from the air sometimes has that effect on steel ,
Id use a small brass wire brush and the vacuum cleaner to remove the particals , then maybe a wipe with a cloth with WD-40 on it .

 

[zamproject]

I’ve read mention that it could be cadmium sulfide or oxide and is toxic.

I don't see how cadmium get there ?!? also CdS is yellow powder and CdO is brown powder

The most rational possible oxide regarding the implicated parts (chassis and screw) is zinc... ZnO...which is white.

edit:
-IT CAN BE CdO from cadmium plating, be careful-

Cheers
Zam

 

[JohnRoberts]

I don't see how cadmium get there ?!? also CdS is yellow powder and CdO is brown powder

The most rational possible oxide regarding the implicated parts (chassis and screw) is zinc... ZnO...which is white.

Cheers
Zam

Isn't aluminum oxide also white?

Probably harmless but don't eat it.

JR

 

[rock soderstrom]

I don't see how cadmium get there ?!? also CdS is yellow powder and CdO is brown powder

The most rational possible oxide regarding the implicated parts (chassis and screw) is zinc... ZnO...which is white.

+1

I have seen this before. I would clean it off as described above, yeah don't eat it and don't sniff it either.

 

[zamproject]

Isn't aluminum oxide also white?

Yes it is, still I think it's zinc here, screw and bolt are rarely Al but zinc plated steel.

edit:
-IT CAN BE CdO from cadmium plating, be careful-

 

[corgan4321]

I saw on this thread about an old chassis on a tube receiver that they used to use a cadmium based coating on some gear.

Sounds like I’d be safe to just wear a mask and vacuum up any debris…

 

[zamproject]

@corgan4321 , thanks for the precision...
Now it seem CdO can also be white, I may be wrong in my previous statement about zinc, so for OP, be careful and take necessary safety precaution about this.

(I'm freaking out as I probably handle and hard clean oxidation on plated chassis in the past thinking it was zinc...)

I'll edit all my previous post

Cheers
Zam

 

[scott2000]

-IT CAN BE CdO from cadmium plating, be careful-

and some of the Mueller alligator clips are not finger licking good.....

 

[JohnRoberts]

For decades I used to strip wires with my teeth. I suspect I have inadvertently ingested some lead from stripping tinned wires that way. Eating lead could explain a lot.

JR