Cleaning Gear, Was Re: Variac Faults

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Christopher Boden by way of Terry Fritz <twftesla-at-qwest-dot-net>" <chrisboden-at-hotmail-dot-com>

Hi Matt :)

Between getting old gear donated (something I do a lot), and UET work I 
spend a signifigant amount of time cleaning old, used gear. Frequently it's 
of the Bakelite vintage and hasn't been touched in 30+ years.

For Variacs (and 99% of most other electronics) there are 2 smells to look 
for, the most common is burnt, once you know it you'll never forget it, but 
Burnt electronics has a very distinctive smell, especially windings.

The other smell is old-storage, is something smells vaguely of mouldering 
books, it's been in storage for a *Long* time, this is a clue to watc out 
for a few things.

As far as compressed air, no. If it's from a compressor you'll just add a 
nice mist of water to the existing crud and make Mud. If it's from a can 
it's likely not gonna get off any heavy crud (though it's GREAT for old 
keyboards/computers/"Indoor" electronics.

For 99% of all old gear you'll need 2 things. Simple Green (the most 
wonderful general cleaner in the world) and "Mother's" (an incredible 
polish that works wonders on brush contact surfaces (especially copper and 
brass). With these two things plus patience and strong arms you can clean 
just about anything.

With Variacs, as a rule if they pass 2 tests they'll outlive you. 1. Does 
it stink? No? go on to 2, if yes, you MAY be able to fix it (I've never 
tried). 2. AFTER you clean it all off and shine up the contact surfaces 
with Mothers (don't move the brushes if it's cruddy, you'll just tear it up 
and cause undue wear on the brushes and surfaces) if it moves smoothly then 
it should work fine :)

If you CAN check stuff out before you buy it (hard to do on Ebay) then 
bring a VOM with you to the surplus place, they're fantasticly usefull for 
testing old gear. Make sure whatever you're testing is unconnected or 
you'll get false readings (and may get bit!). :)

Variacs are rather hard to kill in my experiance. I've pulled 150+amps 
through 3 ganged 30A GE Powerstats without a problem. I've only killed one, 
a 5A model that let it's smoke out after several long runs at ~12A.

Simple Green cleans just about anything from computers to HV gear. Anything 
metal that you wanna shine, Mothers works (I've used it on everything from 
stationary steam engines (Brass, Aluminum, etc), 3 motorcycles and counting 
(Chrome....LOTS of chrome), and HV gear (Copper, brass, etc). It looks like 
Noxema (comes in a similar shaped can too, Red with a white lid). Also, 
Simple Green stinks almost as nicely as Ozone :)



>Original poster: "Matthew Smith by way of Terry Fritz 
><twftesla-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>
>
>Thanks for the answers folks!
>
>
>Jonathan Peakall:
>>I would avoid spraying variacs with WD-40
>>or similar to free them up, it can affect insulation and attracts dust.
>
>The whole bit of kit looks rather aged - loads of CTs, meters, etc. 
>Assuming that by bid is successful, how does (clean) compressed air sound 
>for cleaning it out?
>
>Cheers
>
>M
>
>--
>Matthew Smith            | Business: http://www.kbc-dot-net.au
>IT Consultant            | PGP Key:  http://gpg.mss.cx
>Kadina, South Australia  | * Tivis Project * Community Connect *




Christopher "Duck" Boden Geek#1
President / C.E.O. / Alpha Geek
The Geek Group
www.thegeekgroup-dot-org
Because the Geek shall inherit the Earth!