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THE AM BULLETIN BOARD => Technical Forum => Topic started by: N4LTA on May 08, 2020, 08:24:03 PM



Title: Cleaning smoked up receiving type variable caps
Post by: N4LTA on May 08, 2020, 08:24:03 PM
I have quite a few smoked up three gang and two gang 365 pF per section variables. A long run in the dishwasher didn't help much. It worked great for the older ceramic variables.

I wish I had access to a vapor degreaser but I don't. Any cleaning ideas would be great.

Thanks

Pat
N4LTA


Title: Re: Cleaning smoked up receiving type variable caps
Post by: W1ITT on May 08, 2020, 08:40:42 PM
In the past I have had good results cleaning fired rifle and pistol cartridges with Calgon dishwashing detergent.  In my case I put the cases, some water and some Calgon in a vibratory case cleaner and let them shake in the soup for an hour or so.  The stuff was recommended  over the other brands by other shooters for cleaning powder residue.  I'd be tempted to try it on capacitors.
73 de Norm W1ITT


Title: Re: Cleaning smoked up receiving type variable caps
Post by: N4LTA on May 08, 2020, 08:48:48 PM
Thanks. Might be an excuse to buy vibratory case cleaner.

Pat


Title: Re: Cleaning smoked up receiving type variable caps
Post by: KC4VWU on May 08, 2020, 11:15:40 PM
Sorry to hear about what happened, Pat. Since then, I've been changing out the flourescent troffers downstairs with LED units. It's way past due and those old, humming ballasts have made me nervous for far too long.

Those air variables have been etched by basically potash, so to get them cleaned up, the process will have to be a bit more aggressive.  You could start by soaking them in full strength Totally Awesome and that can be found at Dollar Tree. It's a great cleaner and cheap anyways, so if you try that first, even if it doesn't work in that case it's still usable for other things. Just DON'T use it full strength on painted surfaces because it will soften the paint. Best to use it 50/50 with water and a good rinse afterwards for painted item cleanup. I put it up against any other cleaning solution on the market for cutting crud.

If they are sure enough etched, maybe the boiling in tomato paste as mentioned on this board years back. Haven't tried that one yet. Another one that has worked for me is the old mag wheel cleaner, and I'm sure everyone here is old enough to be familiar with it. The stuff from hot rod days past that you'd use on those ET slot mags that would irritate your skin if it got on you and make you look for the nearest faucet to wash off. They'll probably come out a little grey looking and you'll have to soak and rinse them good in distilled water.

The last option is soda blast. I haven't tried this yet either, and yet again it will turn out a matte finish, but if it makes them any better than what they are and usable, that's a plus. Another option is to tumble them in a in a mildly aggressive media, maybe start with finely crushed walnut shells and work your way up in different grits/media if necessary.

Hope the suggestions help. Sounds like you were insured, so even though it won't totally take away the pain, it sure eases the sting a little bit.

Phil


Title: Re: Cleaning smoked up receiving type variable caps
Post by: KD6VXI on May 08, 2020, 11:39:03 PM
Vinegar?

With deionized wash after....?

--Shane
KD6VXI


Title: Re: Cleaning smoked up receiving type variable caps
Post by: W1RKW on May 09, 2020, 06:30:50 AM
something to try using the dishwasher again. instead of the powder detergent try a Cascade detergent pod or 2. You know the colorful pods kids like to eat.   I don't know what they put in these pods but they removed all the iron deposits on the inside of my dishwasher and made it sparking new in one wash cycle.  We've always used powered detergent until this one time the wife came home with a container of pods.  I was amazed at what I saw.  So amazed we're back to using powder.  It scares me to think what's in the pods and what would be on the dishes, utensils and glassware and subsequently ingested..


Title: Re: Cleaning smoked up receiving type variable caps
Post by: WBear2GCR on May 09, 2020, 10:43:37 AM
Pic of the current state might be good.

I like ZEP 505 - from the big box home stores.
Removes most stuff very well. (take caution on painted surfaces - test first)

Ought to take everything that is NOT etched in right off.

The other way to go is with an acid treatment.
The Dollar Tree people sell several (or before the big V they did) potent ones:
toilet bowl cleaner, liquid blue squirt cap
CLR type "rust remover" (green bottle) and
they used to have a small brown bottle of "rust remover" which actually
had mild hydrofluoric acid!

(read the small print and see!)

Test first on random aluminum...

Vinegar + salt releases HCL... tomato paste, puree and the like are
mostly citric acid...

                   _-_-


Title: Re: Cleaning smoked up receiving type variable caps
Post by: Detroit47 on May 09, 2020, 10:56:41 AM
how about Tarn-x. I have used it for cleaning random stuff just a thought. I have used the stuff that is used for Air conditioner coils before. It is pretty aggressive.

John N8QPC


Title: Re: Cleaning smoked up receiving type variable caps
Post by: N4LTA on June 01, 2020, 07:38:51 PM
i ended up buying a 10  liter ultrasonic cleaner from Amazon . i have ordered some special cleaners for it but hot water and Dawn did a god job.

Pat
N4LTA
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