[edisonwu]

I receive some vintage tubes today. Some are from late 1940's and some early 1950's. Testings are all strong. The only problem with them are the pins have been heavily oxide coated over time. I believe they have been put in machines and just sat there (not been used) for decades. Does anyone here try any chemical ways to clean out the oxide without eroding or damaging the pins? I know sand paper is a solution but it's kind of unefficient and sometimes hurt the pins.

 

[mrarroyo]

Use a toothbrush to remove the heavy crud (a brass/copper type would work if you are very careful). Then get an old socket and plug in and out a few times to remove the rmaining oxidation.

 

[TURBO]

I clean my tubes pins with a very thin layer sand paper from Home depot. At the end, I use 90% alcohol to clean the residues and also to clean the tubes. I use alcohol to get rid of any hands grease, left over the tubes.

 

[edisonwu]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Use a toothbrush to remove the heavy crud (a brass/copper type would work if you are very careful). Then get an old socket and plug in and out a few times to remove the rmaining oxidation.

This is one of the ways I have thought of, feasible but kind of rude

The tubes are 9 pins small preamp tubes and date codes were printed on the bottoms. I have to clean the pins very carefully in order to not hurt the white chalk printed codes as well as the printing on the tubes. It's hard! What actually I am thinking about is to use specific chemical matter like hydrochloric or sulfuric acid to break down the coated oxide. But acids may erode the metal pins at the same time and operation of them are too dangerous. I know some tube dealers decompose oxide by electrolyzing them. It must be the best way to refurbish tube pins.

 

[edisonwu]

Quote:

Originally Posted by TURBO /img/forum/go_quote.gif I clean my tubes pins with a very thin layer sand paper from Home depot. At the end, I use 90% alcohol to clean the residues and also to clean the tubes. I use alcohol to get rid of any hands grease, left over the tubes.

Thanks, I will try alcohol.

 

[Uncle Erik]

I've cleaned many tube pins with 0000 (four-odd) steel wool. It's easier to use than sandpaper and is very fine. It will remove the oxidation, but should not remove much more.

There are a few things to be careful of, though. The steel wool drops off fibers, so do not clean the tubes over the chassis. It will fall in and potentially cause problems. Do it over a newspaper. Second, you'll have a few fibers left behind on the tube. Buy a small, cheap painting brush ($1 or less) and trim the bristles back to make the brush stiff. This will brush off any residual steel. It's useful for dusting, etc. as well. Third, they put a light oil in steel wool to keep it from rusting. Cleaning the pins will leave some oil on them. I always use a paper towel with denatured alcohol on it to clean the oil off the pins. Finally, use something like De-Oxit on the pins to keep them nice.

This takes a little time and effort, but the tubes clean up nicely.

 

[Old Pa]

First, remove the big stuff by light mechanical abrasion (ie. wipe them off using mild abrasiv like Fitz polish) Then CAIG's DeOxit if they are common metal or CAIG's ProGold if they have precious metal plating. This will clean and condition the pins for optimal mechanical connection.

 

[Copperjacket]

Try Coca-cola at your own risk!!! Seriously Coca-cola is an amazing cleaner - put a dirty copper coin in the liquid and leave it overnight and see for yourself.

Suggest you stand the valve upright with the pins in Coca-cola but just below the level of the base. You will probably need to leave it overnight then just clean off.

 

[Happy Camper]

Quote:

Originally Posted by edisonwu /img/forum/go_quote.gif This is one of the ways I have thought of, feasible but kind of rude The tubes are 9 pins small preamp tubes and date codes were printed on the bottoms. I have to clean the pins very carefully in order to not hurt the white chalk printed codes as well as the printing on the tubes. It's hard! What actually I am thinking about is to use specific chemical matter like hydrochloric or sulfuric acid to break down the coated oxide. But acids may erode the metal pins at the same time and operation of them are too dangerous. I know some tube dealers decompose oxide by electrolyzing them. It must be the best way to refurbish tube pins.

Electro-chemical cleaning does very good but you couldn't pull it off with a tube unless they reglass them. All the glass markings would etch off. How would you run current across the pin? They may dip them in a bath of low voltage acid but would adversly affect the base material.

I used to clean metal ion source parts for mass spectrometers with mix of DI/RO water and sulfuric acid with a 30 vdc power supply. The parts would oxidize heavily with anesthetic gases, oxygen/nitrous oxide mixes and 2400 vdc. Cleaned them quickly and got every surface.

Never try this at home. Very toxic vapors.

 

[emericanchaos]

i wouldn't even mess with it bro. it'll prolly oxidize again anyway may as well just leave the oxide armor it has on it.

 

[MaloS]

on the coke one - much faster if you warm it up, boiling coke is one of the best bathroom cleaners ^.^

 

[mikeg]

I never tried to clean tube pins, but I just stick the tubes in, and play. The sound has always been consistent among the same kinds of tubes, and they sound just fine. I once asked someone, who's reall knowledgeable about tubes, whether there's a need to clean and align tube pins. I was told not to bother doing this, but to just stick the tubes in, and play the music. So far this advice seems to have been right.

 

[edisonwu]

I just soak the pins in lemon juice I bought from superstore. I will leave them over night. Wonder if I still need aditional hard scrubbing with brush after that. I should try Coca cola if lemon juice doesn't work.