contact burnishing tools?

[coppercone2]

Has anyone used these file look a likes called contact burnishing tools?

Sometimes I might take apart a old switch to clean the contacts. I typically use rubber abrasives or scotch brite.


It does seem convenient for use when you can't fit anything else.
https://www.specialized.net/jonard-ob-1-3-economical-contact-burnisher-set-3-5-3-piece.html

If you CAN take apart the switch to get easy access to the contacts, does this tool have any benefits over abrasive polishing?

[floobydust]

I think you have to be careful and discern what type of contacts you are dealing with.

I worked with a telecom/railroad tech and he said the best is to use paper as an abrasive, like a sandpaper.
Put in a strip of paper or a business card, squish the contacts a little and pull it through. You can see the black oxide rub off onto the paper. This is for low level signal contacts, then I'll put PPE contact cleaner on them to prevent oxides from building up again. This has worked on small relays and switches for me, for many decades.

Next was an eraser, you can get small pencil-style ones and that works on rotary switches well with the silver/sulfur oxides they get. As a soft abrasive.


The "contact burnishers" he advised only on high current contacts that get pitted and are not simply plated. Like motor starters and contactors. Really rare, I haven't used them in decades. They make me cringe, very destructive filing metal away.

[coppercone2]

so it is infact a file ? the description makes it out to have magic powers of some sort

[coppercone2]

Designed for use on fine relay contacts, these burnishers are the perfect tools for removing the oxide layer from the precious metals of fine relay contacts. These burnishers feature the following:

    Plastic insulated handles allow them to be used on live contacts without any shocks or shorts
    Removes the oxide layer and any corrosion off contacts without leaving filings or debris
    Packaged in a clear plastic bag to protect the burnishers from grease and moisture
    Includes (3) Fine Relay Contact Burnishers

 

are you sure your talking about the same tool? I heard of files being used to like, true up some mangled ass contacts, but this is supposed to be a ultra-fine tool...

https://jonard.com/contact-burnishers-burnisher-files


I don't understand how it might work. I thought it might be very hard and also totally rounded. but I have trouble imaging how that could work to clean a contact.



It clearly says it does not leave fi-lings. Jonard is a pretty reputable manufacturer, I don't think they would lie that crazy...?



I have a weird "file" or "burnisher" in my tool kit (they call it 'reamers" but its not a reamer its more like a ribbed 'broach' wire set, its not what you would normally call a reamer???) for cleaning oxyacetylene welding equipment. In addition to the wire 'reamers' the flat bit looks like a file with a few linear indents on it. I think you are supposed to drag it over the tip of a nozzle if it has some flux residue or sputter on it, so it rips it off. I would say its very lightly textured like its been rolled or something (not cut, smooth). If you drag it over the nozzle the 0.2mm around the hole does become polished. Its very bootleg/cheap looking but it does seem to work, though I never really used it (I use a wheel and then ultrasonic clean my nozzles). its like a not sharp scraper or something 

I thought it might be something like that, but it does not look like that, I don't see any intended lines on it, it looks more like a rough texture for the Jonard thing . The picture makes me think its a fine sanding stick. But it claims its something else.

[floobydust]

I have seen them not like a file with grooves, but instead rough etched finish or sintered, like a nail file. Basically metal-backed sandpaper.

"GC 9337 Contact Burnisher removes oxide and corrosion from relay and switch points. Safely cleans platinum, gold, tungsten, and silver."
I'm skeptical - gold is so soft and very thin, who is spewing this malarkey.

"Non-Residual" contact burnishers leave no filings, grit, dust or film on contacts to start a new carbonaceous build-up. They are economical and flexible, with enough stiffness to apply the right pressure to the contact face offering minimum wear on costly contacts." source

These tools seem to go back to early telephony even late 1920's. Popular use on pinball machines.

The fiberglass cleaning pens are an option too.

[coppercone2]

I get what your saying but it just implies that their just making shit up 

thats why its so interesting, i know you can take off gold with anything even wet polish

[floobydust]

I view it as a very old tool, say 100 years old and like one said it's for clearing carbon buildup from arcing.
Back then, precious metal plating was thick and things built to last, snake oil was a hot seller too. So I don't believe the claims but in an era of misinformation - try it then.
I did and it destroyed the contacts because it's just too abrasive even with just a few strokes that is the guideline in 1950's literature.

Name a metal or abrasive surface finish you can use on gold and silver that does not destroy them 

[coppercone2]

Burnishing is supposed to be non abrasive thats why its so hard to wrap my head around this.

I don't wanna buy it because it looks like a total joke, I just have some other jonard tools that do exactly what they are suppose to and are quite nice so its really bugging me, kind of like if keysight was selling healing crystals. Well their not a pillar of the community or anything like that, but its mostly usable.

[Doctorandus_P]

I have had some good success with using paper to clean contacts such as the rotary switch of a DMM. But the abrasive effect of the paper also wears down very quickly. It's like 4 or 5 wipes, then move the paper a bit sideways and use fresh paper. I use simple regular 80 gram/square meter paper. The whiteness of the paper (before use) is also a good indicator for the dirt yo take off the switch.

Also, the files you mention from that website, look they are made of metal. When folding a piece of paper a bunch of times you get an object that is a deformable and forms around rounded contacts, and thus cleans better. with a metal file and rounded relay contacts you get a very high localized pressure that is more likely to damage your relay contacts. Lots of switch contacts have thin coatings.

But also beware of what you are doing. For example silver is used for relay and connector contacts, and it readily oxidizes into ugly looking greyish to black silver oxide. But silver oxide is also conductive, and attempting to clean it all off will just wear your contacts quicker.

[nctnico]

I second the suggestion of using paper. I tend to use paper + some form of alcohol to clean contacts. One thing to keep in mind is that contact plating is often thin and soft. If there is dirt on the contacts, they need very gentle cleaning. However, worn contacts are beyond resque.

[Jeff eelcr]

I used one for many years, started on pinball machines.
The one I had was a pen style, it held many thin replaceable blades.
Thin strong blades can give access to areas not easy to clean without time consuming disassembly.
The blades are similar to very very fine sandpaper but last a lot longer.
Pressure is what can cause damage to the contacts, to much and you remove more material than required and wear the blade and contact faster.
Jeff

[floobydust]

I don't fully understand "burnishing" with that hand-tool.
It appears to be using high force (compression) to level out the dips and valleys on a roughened metal surface.
I think if it was any good, there would be more than one or two companies offering the hand-tool for doing contacts 

[jpanhalt]

For relay contacts and similar I second @nctnico in the use of paper, but a special type -- a fresh US dollar or other denomination.  I am sure other types of paper must work, but the hard fiber content of the dollar helps.

History:  Years ago (mid-1950's), I was flying an RC plane at Whittier Narrows dam in California.  It was new at the time, but old fashioned by today's standards and had a relay controlling the rudder-only escapement.  I was having problems and one of the old grandads of RC (I believe it was Babcock, https://vintagercfiles.com/Files/Babcock/Escapements/Babcock_Mark_II-Super_Compound_Escapement.pdf) saw me struggling and suggested using a dollar bill to clean the contacts.  It worked.  Models don't have escapements anymore, but I still remember how well that advice helped and have used paper money for minor cleaning (burnishing) of other contacts since. Just hold the contacts closed while passing the paper through it.

[coppercone2]

you can burnish by hand with a ball bearing, it looks like weird polish.. I tried it on a stainless steel spatula by wiggling it in a tight pair of knipex. it replaces the ultrafine brushed texture with a reflective one. you need to hold it hard and move it back and forth so it rotates under pressure . its not consistent but there are highly reflective patches

but the knipex plier wrench has massive pressure, like it will deform fairly hard objects. there is no way you can get that with the tool shown. unlesss its some trick like flat diamonds or something, but I still imagine you need very large pressure

If you get a large ball bearing and rub it on copper it should burnish it, but also probably dent it


with foils like a gum wrapper, you do get something if you press on it hard with a fingenail top (not scratching), it gets smooth and nice looking if you "roll" it.



For maching burnishing, I always thought it should take off.. it would save alot of peoples lungs. if you talk to a old surface grinder they all have lung problems. if they had the option to burnish, better lungs. If someone figured out how to implement it right, it could get rid of alot of dust... now they have masks but alot of people would be alive if they figured out how to implement more burnishing in the 60's .. that and electropolishing. those two process you might be able to get away with a clean bill of health on a 'old timers' 'safety' procedures




I do still have experiments to do on electrocleaning relays. I did successfully electroclean a VNA test fixture (gold), stainless steel is easy to electropolish, but I have not tried relays and switches yet. you can get most mill scale off without a dipping tank too, but that one makes some fumes. When I restored my muffle furnace, I did use electrocleaning to get rid of most of the rust on the chassis. It still needed a stringy wire wheel at the end, but it must have gotten rid of 90% of the dust from rust. The new paint strippers are pretty benign too (ethyl benzene) but they smell horrible. I figure that a chemistry oven might have had some nasty residues on it, perhaps embedded in the rust... so getting that off without it going airborne was smart.

[tooki]

For relay contacts and similar I second @nctnico in the use of paper, but a special type -- a fresh US dollar or other denomination.  I am sure other types of paper must work, but the hard fiber content of the dollar helps.

History:  Years ago (mid-1950's), I was flying an RC plane at Whittier Narrows dam in California.  It was new at the time, but old fashioned by today's standards and had a relay controlling the rudder-only escapement.  I was having problems and one of the old grandads of RC (I believe it was Babcock, https://vintagercfiles.com/Files/Babcock/Escapements/Babcock_Mark_II-Super_Compound_Escapement.pdf) saw me struggling and suggested using a dollar bill to clean the contacts.  It worked.  Models don't have escapements anymore, but I still remember how well that advice helped and have used paper money for minor cleaning (burnishing) of other contacts since. Just hold the contacts closed while passing the paper through it.

I do not recommend doing this with today’s money, because one of the security features in many modern banknotes is rub-off ink. The last thing you want is the banknote depositing ink on the contacts!!!

[coppercone2]

ideally you would wanna launder that money. perhaps the treasury should sell strips of clean money for cleaning purposes. They do shred it. Instead of shredding it they could wash it and sell strips.

Caig brand towelettes are pretty robust and a bit abrasive BTW. Expensive though. Not as thin or papery as money. I use them as a q-tip replacement. But they are very tough, you can drag them through stuff and it won't really fray.. cotton I think

Dragging a strip of that through a relay contact might clean it good, but I don't think it will have the same effect as 'paper' money


caig can partner with the treasury to sell a new contact restoring wipe lmfao. I wonder if this would end up with north koreans sewing them back together to make counterfeit bills. Maybe if you perforate it with a pattern. But I can see some north korean women sewing it under a microscope to reassemble dollars