Lubricate pots?

[Axtman]

How do you guys lubricate a stiff potentiometer control?

I recently had two controls on a Fender amp that were hard to turn and even squeaked when rotated. I tried DeOxit with no luck. I finally had to disassemble the pot, clean it and lube up the plastic shaft with Vasoline. It works better but was sure a hassle to do.

If I had to do it again I might have lightly sanded the plastic shaft. My theory is that it might have expanded or deformed over the years. Maybe due to the set screw pressure.

[Enzo]

A couple trips with Deoxit usually dilutes the hard grease after a bit.

[garytoosweet]

I use MG Chemicals Nu-Trol which works great 99+% of the time.

If it's really stuck and scratchy a few rounds of deoxit with wd40 gel lubricant. The gel lubricant works great but it foams and is best to remove pot from the amp before applying.

[nevetslab]

How do you guys lubricate a stiff potentiometer control?

I recently had two controls on a Fender amp that were hard to turn and even squeaked when rotated. I tried DeOxit with no luck. I finally had to disassemble the pot, clean it and lube up the plastic shaft with Vasoline. It works better but was sure a hassle to do.

If I had to do it again I might have lightly sanded the plastic shaft. My theory is that it might have expanded or deformed over the years. Maybe due to the set screw pressure.

AS much of a PITA it is, when faced with controls that aren't available anymore, this IS the process to restore them. Besides DeOxit on the resistance track, I also use Red grease (axel grease from bicycle/automotive applications) for lubricating the shaft, and mechanical bushings. Where you get stuck is the controls which have staked-on rotors which will NOT come apart. All you can get at on single-section pots of this nature is getting the cover off, making it easier to lubricate the wiper/resistance track. But, those won't allow direct lubrication of the shaft/bushing joint. So, you're up to using a solvent, followed by a viscous grease or lubricant that can be seeped into the shaft/bushing and exercised to get it to seep into the joint.

[Jon Snell]

Back in the 60s, before bespoke cleaning materials were readily available, the favourite 'repair' was old engine oil with plenty of carbon deposits but this only got me out of the customers house when working for a TV rental company as they wouldn't purchase new controls.
I now use, with great success, firstly Electrolube Contact Cleaner for the carbon track. When it is clean apply a squirt of Electrolube Contact Treatment Grease.
Works everytime.
Some techs use oil on nylon shafts. That will cause the nylon to stick as nylon is self lubricating and expands with petro chemical products!

[Enzo]

The old original Tapco mixers had something on the pot shafts that would stiffen up to the point you couldn't turn them. Tapco had cans of some sort of solvent - I forget what - with a chemical name. I will make a name up, ethyl phthalate. it wasn't that. but sounded like it. It came in a plain tin paint can.

[The Dude]

Yep. I had one of those years ago. They should have come with a vise-grip as an accessory.

[Chuck H]

The lubricant used in the shaft is not the same and not intended to be any part of reducing friction on the electronic mechanism. That said, the only way to reduce rotation torque is to reduce the viscosity (and/or space tolerance) of the lubricant in the shaft bearing without allowing it to bleed onto the electronic mechanism. I say this because the lubricant on the shaft bearing is sometimes not compatible with electrical conduction. The mechanism affecting rotational torque is the shaft bearing. That tolerance and the lubricant used determine the rotational torque. It's a bad idea to flush that lubricant onto the electrical contacts, but,.. It's not an uncommon consequence of flushing a pot with solvent and though it doesn't always cause an immediate problem, the higher viscosity lubricant infiltrating the electrical contacts can eventually gather both external and internal (wear) dust and cause problems in operation. That said...

I'm an advocate of using spray cleaners directly on the shaft bearing joints of stiff pots to reduce rotational torque. You can always spray cleaner into the track window to clean electrical contacts in the event that a problem occurs. So...

Spray solvent type cleaner directly on the bearing joints and it will flush some lubricant and reduce it's viscosity. But be prepared to clean the pot at the track/contact window at a later date in case the flushed bearing lubricant causes any trouble on the electrical contacts.

That's a way more complicated answer than necessary considering that common sense should be adequately informative in this matter. But there it is, spelled out.

[mozz]

Yep. I had one of those years ago. They should have come with a vise-grip as an accessory.

Wow, i had one of those 35 years ago. I think some knobs were broken off too. Tapco into a Coliseum Slave, don't even remember who made the amp.

[bsco]

Those main volume pots remind me of the Shure Vocal Master heads....I still have one stored away somewhere...after cleaning pots with Deoxit, I use just a drop or two of oil on the shaft and rotate the shaft a few times to work it in...might not have the quite the same torque but it works for me....

[g1]

Some techs use oil on nylon shafts. That will cause the nylon to stick as nylon is self lubricating and expands with petro chemical products!

I think this addresses Axtman 's comment about the 'expanded or deformed' shafts. I've come across it before too. I think certain control cleaners that may have been used in the past cause swelling of the plastic shafts of some controls.

[Chuck H]

Some techs use oil on nylon shafts. That will cause the nylon to stick as nylon is self lubricating and expands with petro chemical products!

I think certain control cleaners that may have been used in the past cause swelling of the plastic shafts of some controls.

I hadn't considered this. Good thing we have the benefit of members with more experience

[Helmholtz]

I did a little research and learned that the main reason for the swelling of PA and other plastics is the chemical element Lithium contained in many lubricants.

While there are Lithium free lubricants, it is generally recommended to use silicon lubricants/grease for plastic parts.