wd40 for cleaning pots

[dayna]

Hello
Over time I have used several products for cleaning pots and the like, namely servicol 7 and deoxit. The servicol 7 audibly works but I find a smooth working pot becomes very fast and almost friction feel, spoiling the "Feel" of the Pot. I remember once reading an article where Ted Fletcher Spoke of using WD40 for many years without issue to the feel of the Pot-Slider. Wondered what people think about the topic.
Mike

[Wonks]

It's normally frowned upon, because WD40 is conductive when wet, but once the solvent in it has evaporated, what remains is non-conductive. It's main purpose is to disperse water from electrical contacts where the regular physical wiping of the contacts should clear the non-conductive material away.

In a pot that's used occasionally, that is less likely to happen, and a proper contact cleaner containing a conductive lubricant (like Servisol Super 10) is better for pots.

I've also read that WD40 can leave a sticky residue that encourages dirt to build up. As a result I've never used it for pot cleaning. The end result may depend on how clean the working environment is and how often the pots/sliders are used.

[James Perrett]

The makers of WD40 have totally confused everyone now by making a whole range of products under the same brand name. So you are almost certainly safe to use the new WD40 contact cleaner product but less safe using the original WD40 spray.

[Wonks]

The WD40 Contact Cleaner doesn't have any lubricant in it like Servisol 10, so will clean the pots but shouldn't make them feel overly 'quick'.

[Tim Gillett]

Hello
Over time I have used several products for cleaning pots and the like, namely servicol 7 and deoxit. The servicol 7 audibly works but I find a smooth working pot becomes very fast and almost friction feel, spoiling the "Feel" of the Pot. I remember once reading an article where Ted Fletcher Spoke of using WD40 for many years without issue to the feel of the Pot-Slider. Wondered what people think about the topic.
Mike

In rotary pots a grease is added to the shaft and sleeve when it's made to give the smooth 'drag' or resistance to turning. Overdoing spray cleaning can wash out that grease, making the pot quiet electrically but too easy to turn. Over time that original grease can also thicken, making the pot very hard to turn, the exact opposite. In principle the pot can be disassembled, the original 'drag' grease cleaned out and replaced with a suitable grease. I've done it occasionally when a new pot wasnt available but it can be tricky work. HTH.

[ef37a]

The fact is, cleaning a potentiometer is rather like using tights to replace your alternator belt. It might get you home but you really need a new one.

Those of us that have been in electronics a very long time will know that this is a fairly recent problem, for a few reasons IMHO. Firstly, in valve gear they HAD to fit high voltage DC isolating capacitors in the signal path otherwise the pot would be very noisy (and the valves wouldn't work anyway!) Usually such caps had zero leakage current and lasted decades...find me a leaky Mullard Mustard?

Enter the transistor. The much lower circuit resistances meant caps needed to be much higher in value, 10uF instead of 0.01uF and therefore had to be electrolytic. These always have a tiny leakage current and I think, over time this damages the pot's track IMHO especially since pots became much smaller and less well made. Old '40mm' diameter pots were totally sealed. Not so their 20mm offspring. The bigger the track the longer it lasts.

The final nail was the jfet op amp. These have such low bias currents that you can do away with coupling caps and save a bunch of pennies and track estate. Trouble is, bias current is not QUITE. zero and it drifts over time, add crap pots into the equation and you are reaching for a can o spray after a couple of years.

Question to those with top end, say Neve gear. Do their pots go noisy?

As to the suitability of WD-40? I have used it for years and way back other products. Almost any 'dust displacing fluid' will make a temporary fix but that just tells you you need to get the soldering kit out.

S'all coming back a bit! Old radios used to have a felt washer under the knob and I always took that as a way to protect the front veneer and give a smooth action to the control. It now seems it also acted as a 'dust seal'? Preventing dust getting down the shaft. I stripped out a 1950s radio a year ago and now remember that although the outside had 5mm of dust and fluff on it, under the chassis it was as clean as the day it was assembled.

That "they don't make 'em like that anymore" just gets more and more true.

Dave.

[Folderol]

As another ex-radio/TV service guy, I completely agree with Dave. You never heard of 'clicky' pots, but they are quite common these days - even when brand new. As for the indent ones intending to fool people into thinking they are switched. A good exercise in how to wear out the track faster - just make the wiper go in little jerks. Yes we have conductive plastic these days (at a cost) which should last longer - well, maybe if the build quality was anything to shout about.

[Martin Walker]

The fact is, cleaning a potentiometer is rather like using tights to replace your alternator belt. It might get you home but you really need a new one.

I love it!

[James Perrett]

While cleaning pots can often only be a temporary fix, I've also found that it can be a fairly permanent fix in some cases too. In particular I'm thinking of the faders on my big A&H mixing desk which were nearly all noisy when I purchased it secondhand. Fortunately it came from a dealer who sent a very knowledgeable engineer to look at it. He replaced the worst pots but the others were just thoroughly cleaned by disassembling them and wiping the track with IPA. Since then they have all been fine - that's a period of 25 years.

And as for never hearing of noisy pots in the old days - my experience was totally different. An awful lot of radios, both valve and transistor, from my youth had noisy volume controls.

[ef37a]

Well that seems perverse James? If you go to the trouble of dismantling the pots you might as well replace them. Preferably with better ones.

Maybe the 'old radios' that Will and I remember are a generation older than the ones you recall? I am talking pre colour telly!

Not that the old old kit did not have the odd crackly pot but these were usually those controls that were very rarely move such as a tone pot. People set them where they liked the sound and it never shifted. Not sure why but when it Was moved, five years later, it crackled! However, spin it back and forth a few times and it would clear.

What were a bit of a problem and an absolute pain to replace were wavechange switches. We did try to clean them but rarely had better than 30% success. The insulator was paxolin same as cheaper PCB and it absorbed all the crap in the air from fag smoke, open fires, kitchens and the contacts would 'track' like a distributor top. Some even caught fire but most just got very crackly and unreliable.

Dave.

[James Perrett]

Well that seems perverse James? If you go to the trouble of dismantling the pots you might as well replace them. Preferably with better ones.

These are the posh super smooth ALPS faders which the vendor considered were too expensive to replace the whole set (54 in all). Like the ones at

https://www.ebay.co.uk/itm/284514950809 ... SwYuphgp8s

The only thing better would probably have been P&G - a full set of those would have cost nearly as much as the whole console. They are fairly open at the top so all kinds of gunk can float down into them and cleaning this gunk from the track seemed to fix things.

Some of the lesser used faders have become noisy again over time but the faders in regular use have all been fine. And if I ever need to clean them I know the right way to do it now.

[nathanscribe]

Depending what we're talking about, it's not always possible to find a match for an old pot in some old gear. Especially when it has a specific obsolete knob/cap, and has to fit a specific PCB footprint/lugs etc. So many times the most efficient or viable way forward is to strip and fix as best you can. Prices of some 'vintage' pots is very high so I've found it can be a toss-up between clean the thing in 20 minutes or spend an hour online failing to find a replacement part.