different ways to remove solder mask - Page 1
Forum section: electronics / beginners

author: ME
author_rank: Frequent Contributor
timestamp: May 22, 2025, 08:55:07 am
content: Is there a way to dissolve solder mask from a pcb other than grinding/scrapping it off?.

author: tggzzz
author_rank: Super Contributor
timestamp: May 22, 2025, 08:58:58 am
content: Quote from: ME on May 22, 2025, 08:55:07 amSo you think removing the solder mask will solve your problem/goal. But what's the problem/goal?(See second paragraph ofhttps://entertaininghacks.wordpress.com/library-2/good-questions-pique-our-interest-and-dont-waste-our-time-2/)

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 22, 2025, 09:07:40 am
content: Dichloromethane might do it, but would probably also damage the PCB core and some components - not worth the hassle.I usually use a curved scalpel blade, or fibreglass brush

author: ME
author_rank: Frequent Contributor
timestamp: May 22, 2025, 10:01:33 am
content: I need to remove the solder mask to fix some damaged tracks,i hoped there was a gentle way to do it,i will ignoor the trolls comment for now.

author: tggzzz
author_rank: Super Contributor
timestamp: May 22, 2025, 10:10:27 am
content: Quote from: ME on May 22, 2025, 10:01:33 amOK; that removes several (now irrelevant) options.

author: jpanhalt
author_rank: Super Contributor
timestamp: May 22, 2025, 10:45:38 am
content: Please ignore:Consider the problem: You are looking for a "solvent" that will affect the top layer of epoxy (solder resist) but not affect the base layer (FR4).To me, "solvent" excludes denaturing (aka chemically burning). There is no such solvent for cured epoxy (or cured silicone rubber). You can denature it with strong acids (e.g., heptane sulfonic acid, which is sold in a paste for removing cured silicone rubber). It will also damage the PCB.That leaves physical methods, i.e., scraping or abrasion. Scraping is easy to control. Abrasive blasting (bead blasting, frozen CO2, sodium bicarbonate, etc.) might be used for very large areas, but blasting is more difficult to control the depth of abrasion. For tracts, I simply use a glass fiber "scratch pen." Amazon and auto supply places have them.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: May 22, 2025, 01:32:05 pm
content: Good Morning ME, (I meant YOU), If you have a Dremel tool, there are several wire wheels available, which might work.

author: ftg
author_rank: Frequent Contributor
timestamp: May 22, 2025, 02:26:38 pm
content: Quote from: ME on May 22, 2025, 10:01:33 amFor this the gentlest solution I'm aware of are the fiberglass pens.That's what we used to remove soldermask from broken traces at the repair shop.I mean this type of thing:https://www.partco.fi/en/tools-and-handtools/cleaning/26609-fiberpen.htmlI have been told that the jank, improvised precision version of this is using stripped cutoffs of suitably thick fiberoptic cable scraps.But I have not tried that myself.I personally just make do with small flat head screwdrivers and scalpels.

author: Simon
author_rank: Unknown
timestamp: May 22, 2025, 05:53:06 pm
content: Quote from: tggzzz on May 22, 2025, 08:58:58 amThere is a fine line between blunt and rude.

author: ME
author_rank: Frequent Contributor
timestamp: May 22, 2025, 06:42:48 pm
content: not the first rude derogatory comment from the guy tho,yes its a fine line between blunt and rude ,his comment crossed it!.

author: tggzzz
author_rank: Super Contributor
timestamp: May 22, 2025, 07:53:53 pm
content: Quote from: ME on May 22, 2025, 06:42:48 pmYou may prefer the style of this well known documenthttp://www.catb.org/~esr/faqs/smart-questions.html, which has useful content.Personally I think it is good but it has become too verbose over time. Points that would help individual posters are too easily missed. YMMV, of course.

author: thm_w
author_rank: Super Contributor
timestamp: May 22, 2025, 10:47:30 pm
content: Grinding is the best way, look at some proper grinders before deciding its not suitable.https://www.youtube.com/shorts/tQA1yW7vW5I

author: Simon
author_rank: Unknown
timestamp: May 23, 2025, 05:31:59 am
content: Quote from: ME on May 22, 2025, 06:42:48 pmAre we done now, can we move on?

author: coppercone2
author_rank: Super Contributor
timestamp: May 23, 2025, 05:40:25 am
content: the ideal tool is a unionized abrasive in a rotary toolIt's what PACE recommends to use on tough jobsThere are many options. Everything from deburring to polishing. Compared to a non unionzed abrasive, it does not get clogged but it does make a mess. For very fine work (ultra fine grits), you need to clean it in alcohol wipe (get it on alcohol while its working) when it gets fouled , but this is for mirror polishing metal.Beware the coarse ones will eat the board and trace. It's best to use them in a gentle tool like a hand polishing pen that stalls easily for small work. ALso useful for polishing contacts. They actually recommend a low speed tool for low heat, (i.e. a pace microchine or a jewelers polishing tool. dremel is too fast for them)

author: jpanhalt
author_rank: Super Contributor
timestamp: May 23, 2025, 05:59:29 am
content: Do you mean "unionized" or rubberized? Cratex are great tools/points to use.

author: coppercone2
author_rank: Super Contributor
timestamp: May 23, 2025, 06:45:21 am
content: yeah something like that, its rubber or leather powder (for tougher ones) with abrasive, very soft ones use silicone rubber instead of a harder rubberThere is some other shit too, IDK what it is. Its like almost felt like but it disintegrates.There is those disks that are something akin to the most nasty unwashed stiff clothing type material ever, it has little strands too. Maybe its little hemp fragments with glue and abrasive in there. Like if you pour laquer on a cloth that dries 'pretty hard' . It has plumbers hemp rope color tones... maybe like sisel buffing wheels, but with coarse abrasive in there. I bet its sisel based... must be a common material for those peopleAnd the stuff that looks like lava rock but its softer (tough as hell black sponge). This one isamazingat mill-scale removal. Its kind of like the tough scotch brite, but non compressible at all. The hard scotch brite ones will bow to pressure.Then there is also the scotch brite materials, which can also work (harder ones), but they really get worn down fast IMO. And its too big for most PCB exposing work (and too floppy/imprecise)Oh and there is micro flap wheels tool. They will work, but the one dremel sells is too big for most PCB work. I wonder if there is a smaller one. This skinny one looks interesting if you get it in the right grithttps://www.aaabrasives.com/wendt-abrasives-112004-mounted-mini-flap-wheel-38-x-38-x-18-shank-a60And if you are getting these, try to get ones that say silicon carbide or diamond laced. The aluminum oxide ones are better for metal. (most of these things described here are available with different abrasive loading).i.e. diamondhttps://www.dedeco.com/diamond-sil-composite-midget-f-fg-mini-3-bx/then the cheap ones are silicon carbide or aluminaOh man, if you can get a dremel sized wirebrush with DIAMOND on the bristles it would probobly be kicking some major ass too........................................................... Like this one but micro...https://us.pferd.com/en/cup-brushes-knotted-standard-twist-long-flag-with-thread?a%5Bdiam-outer-inch-tds%5D=4+Inch&a%5Bdiam-filament-material-inch-usa-string-tds%5D=.020+Inch&a%5Bgrit-size-tds%5D=270But I hate those micro wire wheels because they are WAY too weak and lose wire too easily. I always get injured and have to get tweezers unless its a safe job (cup brush in a hole)Also get some old boards to practice on, performance is all over the place. For some boards certain tools will smear/get hot. I think there is a range of solder mask types.I personally usually scrape them, because its the cleanest way, because there is too much dust. I don't always want to do the whole working outside and washing the PCB thing... for small jobs anyway. But its invaluable for broke PCB that need alot of work on them. And I always do it for burn damage (scraping burnt PCB sucks ! its worth the cleanup and effort to get motorized)**last year I got the pen polishing tool, which I did start to use with rubber cup silcone carbide abrasives for trace exposing, if I renember it. This is convenient, much more so then the dremel, for small jobs. IMO its easier to mess up board from scraping, especially with heat damaged traces! Getting the dremel and flex shaft out is too much for me (and its loud)I should get into the habbit of using the mini electric screw driver and rotary tool more... my hands are gonna get messed up if I keep doing manual work with them.. its kind of a hassle but manual hand electronics/fabrication related 'tiny' labor starting to wear thin on me. I started to notice pain in forearms if I do alot of this.