Trying to find an oxide removing pen/stick for soldering corroded components - Page 1
Forum section: electronics / beginners

author: Cyber Akuma
author_rank: Regular Contributor
timestamp: May 20, 2024, 02:24:44 am
content: During one of the many of the soldering tutorial videos I was watching, one of them (I can't find which one it was I saw though) I saw the person at one point use some kind of pen/stick which had a bit that looked a pencil eraser remove the oxide from a heavily oxidized component's leads fairly quickly and easily, though I didn't put much thought into it back then.I was recently putting together some cheap soldering DIY kits I got from Aliexpress to practice my soldering and noticed that many of the components had leads that had some heavy corrosion. I tried using fine sandpaper and rubbing alcohol to clean it off, and it sort of worked but not too well, plus it was difficult to make the sandpaper contact with the smaller component's leads this way.I think I might have to use that pen for these kits, but I can't find the video again or remember what it was called. When I try to search for it I keep getting results for flux pens or conductive ink pens, which is not at all what I am looking for. This pen looked to have some sort of rubbery or silicone tip that acted abrasive. Anyone here know what it's called so I know what to look for?

author: geggi1
author_rank: Frequent Contributor
timestamp: May 20, 2024, 02:44:24 am
content: Flux-pen

author: abeyer
author_rank: Frequent Contributor
timestamp: May 20, 2024, 03:02:40 am
content: A fiberglass scratch brush, maybe?

author: coppercone2
author_rank: Super Contributor
timestamp: May 20, 2024, 03:50:28 am
content: fiberglass scratch brush works for soldering but for contacts it will actually scratch them up its aggressive. invaluable tool, I keep it in a box so it does not dirty things up with its fibersyour looking for a abrasive rubber pen, its a material used for dremel wheels and burrs too, big boy versions for welding exist also (some are leather with abrasive too)a mild version is used for erasing ink pens

author: Muttley Snickers
author_rank: Unknown
timestamp: May 20, 2024, 04:03:36 am
content: I always give old toothbrushes a second life, they are just too handy to throw away particularly for various cleaning applications.

author: coppercone2
author_rank: Super Contributor
timestamp: May 20, 2024, 04:43:57 am
content: always a good idea to try the lightest brush first before you get heavy with it because it has lower chance of damage, if you have the patience

author: TomWinTejas
author_rank: Regular Contributor
timestamp: May 20, 2024, 03:01:28 pm
content: Staedtler Mars 526-61 eraser works pretty well and is not as aggressive as a fiberglass pen.https://www.staedtler.com/intl/en/products/pencils-and-accessories/erasers/mars-rasor-526-61-eraser-pencil-m526-61/But it's also worth having a cheap fiberglass pen you can pick up off AliExpress... just remember to be gentle.

author: Cyber Akuma
author_rank: Regular Contributor
timestamp: May 20, 2024, 03:34:37 pm
content: Quote from: geggi1 on May 20, 2024, 02:44:24 amNot a flux pen, this is to basically physically scrape off oxides, normally a heavy amount.Quote from: abeyer on May 20, 2024, 03:02:40 amSounds like a "scratch brush" is indeed what I was looking for. So many varieties and types though, and most seem to be intended to scrape off surfaces for painting or to clean jewelry, going to have to see what kind are intended for electronics, especially soldering.Quote from: coppercone2 on May 20, 2024, 03:50:28 amI am a little confused by this post. You said a fiberglass one will work, but it will also damage the contacts, yet it's also invaluable? I am not sure what you mean. Do you mean the pads on the PCB?Also not looking for something that would go in a high power tool like a Dremel, I meant a pen that you would rub on the oxidized leads by hand to scrape off the corrosion.Quote from: Muttley Snickers on May 20, 2024, 04:03:36 amWould those be abrasive enough for such a thing? I mostly see people use old toothbrushes to clean off flux after they are done soldering, not to scrape off oxides before they can solder something.Quote from: coppercone2 on May 20, 2024, 04:43:57 amWhat would the lightest be? I see ones made from different materials. Fiberglass, steel, brass, etc. Which one should I start with? Also would I need to use different brushes if I am cleaning corrosion off the pads of a PCB and off the leads of a component? I would assume you can use a stronger more abrasive one for the leads right? Or am I wrong on that?Quote from: TomWinTejas on May 20, 2024, 03:01:28 pmHuh? That looks more like a paintbrush. Is that also for cleaning electronics? The ones I saw had a tube-like tip, not splayed out like that, and seemed much firmer than that.

author: coppercone2
author_rank: Super Contributor
timestamp: May 20, 2024, 05:45:32 pm
content: for flex abrasive, you can put rubber/silicone or leather on a dremel or 1/4 inch rotary in a burr or use it in a eraser. the one in a eraser will be milder grit. Not sure if they have specialty ones for really tough work. I have some slightly flexible stones (idk if its 500 year old rubber that aged or just like tar+sand bars) for fine stoning by hand, but its like a airplane soap.fiber scratch pens will scratch the shit out of what your doing. its fine for soldering but IDK if you wanna do that to a relay or switch, it looks chewed up after wards. Keep in mind switches and relays have special coatings, some of them, so you need to be as mild as possible to get any results. usually their screwed. some relays seem to be designed for cleaning in mind (big relays), there is a specialty tool for this, called a relay hone or something, looks like a nail file. I never used it. IDK if its shady or approved. usually you clean them by dragging paper through it, which is a super fine abrasive, to get rid of a little of the soot. not sure if anything is more mild then some paperthe tooth brush is the most mild. followed by a stiff brush (stiffer nylon), then brass, then steel, then stainless steel, then even if you can afford it they got diamond covered stainless steel brushes, but I have only seen these for steel working, and their $$$Where rubber stands in agressiveness IDK. It depends on the grit. For the dremel you can get at least 3 different versions, and specialty workers (jewelry) have a gamut of different grits available in different rubbers in different concentrations.How it all works out and what order you should go, it really depends on how much experience you have, but trying a toothbrush first is a safe bet. For a rubber abrsive its type of grit (carbide, diamond, alumina,etc), concentration, type of rubber (silicone, leather, rubber, etc), shape and grit that efffect the cutting/polishing ratethe important thing is to protect your lungs though, wear a mask, their bad for you. their commonly used to polish irregular shapes like stones or fine mechanisms. they wear quickly on a rotary tool but the results are excellent. if you cut thin steel boxes, the coarse rubber is king for deburring, so long you have alot of them... you can get a nasty burr silky smooth

author: jpanhalt
author_rank: Super Contributor
timestamp: May 20, 2024, 06:01:47 pm
content: 1) I second a scratch brush as something that looks like a flux pen, but isn't one. I don't think there will be a special one made for electronics, unless it is a regular one re-branded with a higher price. Mine is about 3/16" (about 6.5 mm) in diameter. My main use is to remove solder resist when modifying a commercial board. I have never used it to prepare wire for soldering.2) Metal oxides are basic (think NaOH), so acid flux works great with them -- consider plumber flux. That is not good for electronics because it causes corrosion for the chloride in it, but if it is just for learning how to solder, then what's the problem. Soldering is the same.3) Nitrates and probably dilute nitric acid will also work and don't have the chloride problem. Just FYI, HCl and FeCl3 etch stainless steel. Nitric acid doesn't. It's the chloride or other halogens. Kester 44 flux has a little bromide (a halogen like chloride) in it as an activator.

author: coppercone2
author_rank: Super Contributor
timestamp: May 20, 2024, 06:09:57 pm
content: and where fiberglass is compared to metal brushes? IMO its way up there. With light pressure it does more cleaning then all the brushes, because the tips are so sharp. It might not remove thick oxide well, but its extremely agressive, since its so sharp. it makes for a good pen tool that you need to use in a tight area with very little room to move around. But it also clogs quickly and gets chewed up, the metal ones last a long time.

author: coppercone2
author_rank: Super Contributor
timestamp: May 20, 2024, 06:12:52 pm
content: Chlorides have a extremely bad reputation in electronics because their hard to clean off for some reason, including HCl. People say do not use HCl on wires.and wires wick chemicals. Molten hydroxide solidifies very quickly, so it can;'t go up in the wire. anything else can. I have seen battery electrolyte (KOH + Water) wick up through a wire that was almost 10 inches long like it was a siphon hose and utterly wreck a GPIB connector (looked like crystal forest) . Usually its only used for magnet wire, which is coated and single strand, so it can't wick anyway.Molten salts (i.e. either hydroxide or tungsten sharpening mix (sodium nitrite etc) thankfully will solidify extremely fast and are unable to really wick up a wire if you are quick, so it might be OK on stranded wire, but I would recommend a ultrasonic clean afterwards, and don't do this for anything important (this is a reminder for Boeing personnel)

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 20, 2024, 06:28:09 pm
content: An old school tool that is intermediate in aggressiveness is a typewriter eraser. Used for correcting mistakes before the delete key was a thing. You might find one on line or in a stationary store. More likely to be in stock today would be an ink eraser. Same concept. Unlike a pencil eraser which is more of a gummy collector, the ink erasers have abrasive embedded and take off the surface layer of paper with the ink.

author: Laval
author_rank: Regular Contributor
timestamp: May 20, 2024, 06:44:08 pm
content: Toothbrush are good but they are sometime cumbersome and cannot always reach crowded part of some PCB. An abrasive rubber/eraser is indeed a good idea.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: May 21, 2024, 10:38:51 am
content: Quote from: Cyber Akuma on May 20, 2024, 02:24:44 amFor any parts that are slightly corroded/oxidised, I use plumber's solder flux. It is not really suitable for electronic assembly, but when "needs must" it works really well. Just wash off the residue with an old toothbrush and plain tap water afterwards. The brand is LA-CO, from LA-CO Industries Inc, Elke Grove, IL 60007-5746, $6.40 for a 4oz jar with a brush in the cap.https://markal.com/products/regular-flux-paste?variant=9204786823215SJ

author: armandine2
author_rank: Frequent Contributor
timestamp: May 21, 2024, 11:26:05 am
content: adjusted for different degrees of stiffness

author: macboy
author_rank: Super Contributor
timestamp: May 22, 2024, 01:53:01 am
content: Quote from: Solder_Junkie on May 21, 2024, 10:38:51 amNo. Just no.The advice against using plumbers flux exists for good reason. You can choose to ignore it if you want, but don't encourage others to do the same.

author: Solder_Junkie
author_rank: Frequent Contributor
timestamp: May 22, 2024, 06:10:39 am
content: Quote from: macboy on May 22, 2024, 01:53:01 amAnd your solution to tarnished/corroded metal is?The flux I linked to is non acidic, while not intended for electrical/electronic work, it really does help when ordinary cored solder is not working, and is an alternative to fibreglass pens/sand paper/scraping with a knife. Even though it is non acidic, I did point out the need to wash it off afterwards.Clearly the better solution is to buy components from reputable suppliers, such as Mouser, or Digikey, but sometimes you have to work with what you have, especially where you are doing a repair on something has been exposed to the elements.SJ

author: tooki
author_rank: Super Contributor
timestamp: May 22, 2024, 07:05:34 am
content: Quote from: Cyber Akuma on May 20, 2024, 03:34:37 pmYou missed the point: the working end of that is the other end: it’s an eraser shaped like a pencil, with the actual eraser encased in wood. Basically a pencil with eraser as the lead instead of graphite. The brush is just for brushing away eraser dust.And that’s exactly the thing I was going to suggest. I use one regularly for exactly this purpose. It’s abrasive enough to make quick work of oxides, but gentle enough to not immediately eat through the leads.They exist in both regular eraser (for graphite) and ink eraser, and I’d recommend getting both, so you can use the gentler eraser for more delicate items. Faber Castell sells a few variants.Just buy a separate pencil sharpener to use with them so you don’t dull your favorite sharpener.I also love the fiberglass pens, but reserve them for tougher cases for the following reasons:1. You must METICULOUSLY clean up the little fiberglass fibers that break off in use, because otherwise you’ll end up laying your hand on them, where they’ll embed in your skin and cause itching. The rubber eraser dust poses no such dangers.2. Fiberglass pens and their refills are more expensive.

author: jpanhalt
author_rank: Super Contributor
timestamp: May 22, 2024, 08:44:13 am
content: The brand Cratex was so common it became almost generic for rubberized abrasives. Often used for spot cleaning and polishing in machine work. There are various grades and even mounted points.Here's just one of the many examples: Cratex #046M Rubberized Abrasive Round Rod 6X1/4 Medium ($8.25 at Amazon USA).

author: macboy
author_rank: Super Contributor
timestamp: May 22, 2024, 02:01:32 pm
content: Quote from: Solder_Junkie on May 22, 2024, 06:10:39 amWhen I come across a component or board which doesn't want to wet easily, I switch to Kester 44 solder, and that always handles it with ease. I have this in a few different alloys: 60/40, 63/37, and 62/36/2 (2% Ag). I've even used this to tin stranded copper wire that has turned black or green with age. It just cuts through. For anyone shopping for this, get the '66 core', which means the flux core accounts for nominally 66% of the diameter of the wire, or 3.3% by weight. The 50 and 58 core are only 1.1% and 2.2% by weight respectively. The point is that if you want to use active flux, then you probably want plenty of it.I do sometimes use a pink or green rubber pencil eraser to clean oxides from board pads. (vinyl or gum erasers will not work). I have actually repaired a few hard drives this way; the interconnect from controller board to the heads is often a kind of pressure contact connector directly to tinned pads on the board. Sometimes those pads are so tarnished they are turning black. A little scrub with the eraser to polish the pad back to shiny metal, and the drive miraculously works again! (YMMV).

author: shabaz
author_rank: Frequent Contributor
timestamp: May 22, 2024, 02:53:32 pm
content: I don't trust myself with the fiberglass pens, and usually use a small scrap of sandpaper/cloth. It's crude but fine for DIY stuff and usually meets my needs (but it will damage the component lead somewhat, since it's so aggressive). The eraser method works surprisingly well (without any noticeable damage), the photos show switch and wire cleaning with the eraser.

author: Cyber Akuma
author_rank: Regular Contributor
timestamp: May 27, 2024, 03:41:56 pm
content: Man, there has been... a lot of arguing here about this.I found the video by the way, here is a timestampoed link on what I was talking about:(EDIT: Seems the site's embedding ignored the timestamp. It's at the 20 second mark)Quote from: coppercone2 on May 20, 2024, 05:45:32 pmI don't want something that would require another tool like a Dremel to use, I wanted something simple that I just use with my hands like those Scratch Pens that were mentioned.QuoteNot sure what you mean. What would be the problem of scratching the leads of a relay or switch? In case there is some confusion, I am only talking about scratching the leads of such devices that you would solder to, not cleaning the entire component itself, just removing the oxidation from it's leads so solder will adhere better when it's too corroded for even flux to help that much with. I am also only talking about preparing the component for soldering, not for doing anything to it after it has been soldered into place.QuoteWhen you're talking about the other brushes, do you mean a scratch pen or an actual paintbrush-like part?What hardness/material would you recommend for the leads of a component? What about the pads of a PCB? I know that the pads/vias can be a lot more sensitive, and old electronics even more sensative than a modern PCB. Would I need a different one for both modern and old PCBs?QuoteBasically a beginner. I don't see how a toothbrush would help though, that would be much too soft. I only saw people using those to clean flux off, not the actual components.Quote from: Solder_Junkie on May 21, 2024, 10:38:51 amI don't think it's a good idea to use any type of flux or solders meant for plumbing for electronics, especially as I am not that experienced with soldering yet.Quote from: armandine2 on May 21, 2024, 11:26:05 amYeah, those look like what I was talking about. Just not sure which ones to get for electronics since most are advertised for other uses. And for different uses.I assume that for cleaning the leads of a component I can use something much stiffer/abrasive since scratching the leads would not really matter?Though from what I understand, the pads and vias on a PCB would be much more sensitive so I would need something far less abrasive?And further still, if I am dealing with repairing or modifying very old electronics the pads/PCB might be worn out and I would need something even more sensitive? I hear that many people have managed to lift or tear a pad from simply attempting to desolder something on such old boards.Do you have any recommendations for what materials/brushes/types of these scratch pens to use for these three scenarios? Or if I even understood the three scenarios above correctly?Quote from: tooki on May 22, 2024, 07:05:34 amI see, I didn't realize it had another end.QuoteEat through the leads? I thought the leads were just a solid piece of metal? Do they normally have a coating or something I should not scratch through like the tip of a soldering iron would have? And do you have any recommendations for what to use on both old and new boards that I mentioned above?QuoteWould rubbing alcohol and a soft toothbrush be enough to clean them up?Quote from: shabaz on May 22, 2024, 02:53:32 pmI tried that but I just couldn't get the sandpaper to make enough contact with the leads to clean them well, and it's not something I would want to use on a PCB itself.

author: coppercone2
author_rank: Super Contributor
timestamp: May 27, 2024, 11:12:10 pm
content: because all the switches and relays have crazy electroplatings and IMO it needs to be polished to like resist further fast wear even if its brass, this is a arc surface. Contacts are mated and don't arc which is a different deal. With a switch it could be dirty, where you can remove the dirt, and it might have electroplating intact. fiberglass might totally destroy it.not the leads, the switch surface, you can clean relays and stuff. usually you drag paper through it. some big relays are compatible with a special relay hone. i mean the part that does not get soldered, it gets dirty toothis thing is really good BTW, so long it does not break, I just got onehttps://www.amazon.com/ARROWMAX-Electric-Engraving-Polishing-Bluetooth/dp/B0B5ZTY8WG. comes with rubber stuff.i noticed because its lower power it does not destroy the rubber so hard like a dremel, it stalls at the point where the dremel would procede when the rubber is under intollerable strain conditions. The dremel is just too powerful for things like sharp tip rubber burrs. the powerful dremel has a use with them, that is deburring (at the expense of destroying the rubber quickly).. but for polishing the low power motor is nice.the finest grit rubber they have nicely cleaned a DMM probe without destroying the plating, and cleaned oxidized tin PCB traces beautifully. if you have a block with a tiny groove for the TH part, it would clean the lead nicely (and you can make this with their diamond burr.I strongly recommend experimenting with electric tools. I also did the damaged contact pads for a big press on IGBT module (but with dremel flex shaft). THey were destroyed and required re-plating, but its been working fine for a long time. The benefit with the electric tool and coarse grits is that you can excavate burnt PCB material, then fill in with a syringe of PCB epoxy (fine needle and careful application).. for very light damage you can scratch with a scribe, but this makes it possible to restore heavy damage (i.e. going 1/2 way deep in to the FR4)the trick is, absolutely under any circumstances DO NOT DROP their micro screw drivers, drills and rotary tools. Pretend its a glass thermometer.

author: tooki
author_rank: Super Contributor
timestamp: June 08, 2024, 08:19:41 pm
content: Quote from: Cyber Akuma on May 27, 2024, 03:41:56 pmYep. I’ve seen a Pace “abrasive stick” in person, and it is indeed just a regular old-fashioned pink eraser of the traditional kind that contains a small amount of abrasives. I can say with confidence that the Faber Castell woodcase eraser pencils for graphite are equivalent. (The ones for ink are more aggressive.) The classic pink bar eraser shown in a post above is exactly the same kind of eraser and works well too.Quote from: Cyber Akuma on May 27, 2024, 03:41:56 pmOops, I had meant to say “eat through the plating on the leads”. Sorry for the confusion!No big deal (most of the time) for soldering, but really bad to do to mating surfaces of connectors, for example.Quote from: Cyber Akuma on May 27, 2024, 03:41:56 pmAlcohol and toothbrush to clean up the fiberglass fibers?? No. You need to vacuum them up or use something like an adhesive lint roller. You do not want those fibers laying around. Alcohol will just push them around, it won’t remove them.

author: richnormand
author_rank: Unknown
timestamp: June 08, 2024, 09:17:09 pm
content: This is what I use:Nail polisher. Variable speed and rotation direction. Battery powered. Cheap on ebay.Assortment of diamond files and such, for the nail polisher.Assortment of dentist tools, the scraper wedges in particular. The hand feel and dexterity is much better than a Dremel for me for a light touch.A fiberglass pen. The brass spikes and others are too damaging and big for fine work.Clean with IPA when done and put a drop of flux before tinning.All done under a real 3D binocular microscope meant for medical dissection.Hope this helps.