Switch cleaner and lubricant

[Donels]

I am going through all switches including, column switches, prior to refitting. The column switches appear to have some sort of grease which is now dry and hard. Rightly or wrongly (probably wrongly) I have cleaned them with WD40, but before doing them all I should probably use something designed for the task. I was thinking of using RS PRO Lubricant Contact Cleaner. This cleans and has a lubricant for long term protection.

Any advice or recommendations before I continue?

Dave

[ericbushby]

Hi Dave,
The contact cleaner is the right way to go. WD40 is very useful at times, but is best thought of as wax with a solvent.
When the solvent has evaporated the wax coating acts as a Water Displacer, hence the name, but can leave a sticky waxy residue and cause further trouble.
Surprisingly WD40 makes a good cleaner and wax polish on painted metal surfaces such as panels and machinery.
I use it as cutting fluid on the lathe. Local spot treatment.
Eric in Burnley
1967 S3SE DHC

[smo17003]

I have used Electrolube CG53A Contact Treatment Grease on my switches after I've cleaned them with a contact cleaner.
RS stock number is 337-5925

Mike

[bloodknock]

I’ve used Servisol most of my working life, always does the job.

[mark030358]

Also, put a higher than usual current through them, just to burn the crud off

[Bitsilly]

I have always used copper grease on earth contacts, can't remember why!
But I just googled it:

'Its great advantage is that it can be used in hot areas (connectors on or near engines) and will not melt, unlike vaseline. Copper based grease is a splendid anti-seize material but has no electrical applications and no acid resistance.'

and:

'The proper product is a Dielectric grease, which is a silicone-based grease that repels moisture and protects electrical connections against corrosion.'

and gosh it is very important to be proper, personally I've never heard of it!

[bloodknock]

Also, put a higher than usual current through them, just to burn the crud off

Not a good plan, the contact surfaces can be seriously damaged, or even welded.

[Andy8421]

Also, put a higher than usual current through them, just to burn the crud off

Not a good plan, the contact surfaces can be seriously damaged, or even welded.

Switches are more complex than they look. Putting aside grungy old grease that has gone hard, or filth and muck in the switch, it is usually oxidation of the contacts that cause low voltage switches to stop working.

In an ideal world, you wouldn't use bare copper as a contact, but something like gold or silver that resists corrosion, or seal the switch from the atmosphere. A wiping action of the contacts as they come together helps keep the contacts clean, but Lucas weren't working in a ideal world and generally their switches use bare copper without wiping.

The best you can do is give the contacts a good clean, then coat with one of the lubricant / corrosion prevention products linked to above.

High voltage switches don't have this problem as the voltage is sufficient to punch through an oxide layer, and the arc as the switch breaks has a cleaning effect - although it can lead to contact erosion.

Overheating a switch to 'burn crud off' is not a good idea, apart from the risks listed above, the temper of the contacts and springs can be lost and the switch will then fail to operate.

Edit: A small anecdote. My first job when I graduated was in the BBC engineering department. At the time, many studios were general purpose and had large jack fields to allow equipment to be reconfigured and plugged to suit. Signal levels were in the order of a volt or two, and corrosion on the jack plugs and socket contact faces was a problem. We were taught to give the plug a half turn forward and back after insertion to clean the contact faces. You can still spot an ex BBC guy by the instinctive twist of a jack plug as it is plugged in. I still give the jack a twist when I plug my headphones into my iPad.

[The Veg]

Dielectric grease is definitely your friend. All my dashboard-switches got a dab of it a few years ago when I had them apart to clean contacts.

Anecdote: my dad had a great tube of the stuff, I think branded as RCA. It was older than I was and bigger than most toothpaste tubes. I little goes a long way so I think it still had plenty in it when I was 20. I can recall the blue and yellow printing on the aluminium tube, worn away on the wrinkles.

[mark030358]

Also, put a higher than usual current through them, just to burn the crud off

Not a good plan, the contact surfaces can be seriously damaged, or even welded.

I'm not sying short them, I'm saying use a higher wattage (for example lamp( than ususal. Ever heard of "wetting current"....

thanks

[skyarch]

I've been using Deoxit D5, spraying the switches and contacts. Available in Music stores that sell guitars, etc. here in the US.
Here's a link:
https://www.guitarcenter.com/CAIG/DeoxI ... or-5-oz.gc

I use it on an Alfa Milano for the Bosch Fuel injection parts. It seems to dissipate moisture. Other than that Dielectric grease.