Abrasive - mechanical "cleaning" - Page 1
Forum section: electronics / general

author: kalel
author_rank: Frequent Contributor
timestamp: October 28, 2017, 06:22:18 pm
content: I have heard about a few different uses for abrasive cleaners so far.Fiberglass pens to remove soldermask, perhaps some other usage?Other materials to remove oxides and prepare certain surfaces for soldering.This is a bit of a general question, when it comes to abrasive - physical materials in electronics, what is used to do what?I might want to have some of the recommended stuff available for future reference, but I'm not sure what is recommended for which usage.

author: SeanB
author_rank: Super Contributor
timestamp: October 28, 2017, 06:40:46 pm
content: Genuine 3M Scotchbrite pads, in both the green and red grades, for cleaning off boards are also a good thing. A little bit of abrasive powder on a wetted Q tip as well is a nice fine area cleaner, will shift those oxides that will not solder. Some waterpaper in 400, 800 and 1200grit as well, a good brand, used in small pieces to clean off that hard to solder bright chrome plating that are on some connectors.Brass polish also has occasional use for connectors that are corroded, using a nice lint free cloth and a new toothbrush. Q tips as well work with it.

author: Ian.M
author_rank: Super Contributor
timestamp: October 28, 2017, 07:04:18 pm
content: Fiberglass pens aren't that good at removing intact soldermask. You have to scrub really hard and the area cleaned isn't well controlled. However once you have broken up the soldermask with a sharp scraper they are great at removing the residue and getting down to clean copper, or for removing oxidisation and/or corrosion from bare tracks and pads. They also do a reasonably good job cleaning tarnished/oxidised DIP pins and solder tags. A further use if set a bit longer for a less harsh action is as a heat resistant brush for wiping molten solder off pads or as a mild abrasive for dealing with tip tinning failure that isn't solved by using a block of tip tinner cleaner.You'll also want a selection of grades of Wet&Dry abrasive paper, from about 200 grit on the coarse end down to 1200 grit on the fine end, some pocket sharpening stones (medium and fine grit), some brass wire brushes for cleaning contacts (a pencil one, and a larger but still small rightangle one with a handle). A set of plain needle files and a set of diamond needle files will also see a lot of use.What gets used on what depends on accessibility, the surface finish desired and the hardness of the material to be removed. e.g. a folded strip of fine grit Wet&Dry paper is useful for dressing burnt open frame relay and contactor contacts in-situ, but afterwards, wet cleaning with alcohol or contact cleaner on a strip of cartridge paper is *ESSENTIAL* to remove any residual grit and debris from the contact surfaces.A Dremel (or clone) with a wide selection of abrasive accessories is also useful.

author: MadTux
author_rank: Frequent Contributor
timestamp: October 28, 2017, 08:36:16 pm
content: There are also chemicals that can dissolve solder mask, Magnastrip 500 and Ristoff C-8 are the ones I've heard from. Wonder what the "magical" ingredients are.

author: Cerebus
author_rank: Super Contributor
timestamp: October 28, 2017, 08:48:19 pm
content: Quote from: MadTux on October 28, 2017, 08:36:16 pmProbably strong alkalis. I find that Sodium Hydroxide solution (and a bit of heat) will strip cured solder mask in short order. Beware though, it attacks epoxy too, it's a question of balancing one against the other.

author: Cerebus
author_rank: Super Contributor
timestamp: October 28, 2017, 08:49:46 pm
content: Melamine sponges are great for cleaning and preparing PCB copper before processing (resist coating etc. etc.).