How to remove a large blob of solder from circuit board? - Page 1
Forum section: electronics / repair

author: CuriousGeorge
author_rank: Newbie
timestamp: September 10, 2018, 01:12:13 pm
content: I made the stupid mistake of running my soldering iron over the project I was working on when the solder that was on my tip fell onto my circuit board. There are many resistors on there and was wondering if there was a technique I should use to do my best to remove it.Here is a photo of the screw uphttps://drive.google.com/open?id=1tEvUp2NfRcnNMPFPvCta38gyot3Q0wdo

author: nanofrog
author_rank: Super Contributor
timestamp: September 10, 2018, 01:40:08 pm
content: Did it actually wet to the pads and passives?If not, you may be able to remove part of, or even all of it mechanically (be very gentle if so). An X-acto knife could be useful here. If it has wetted anything, carefully cut through the blob around the edges of the IC as it doesn't adhere to the plastic portion (less to mop off with the method below).Otherwise you'll need some decent quality desolder braid/wick and additional flux to mop it off, then rework any of the passives that require it (doesn't look like it got underneath the IC to me).

author: Jeroen3
author_rank: Super Contributor
timestamp: September 10, 2018, 02:21:41 pm
content: Do you use the same iron to solder copper gutters?If you have a small high power iron you can probably "cut" the solder away from pads, and mechanically remove the blob. And using some solder wick to remove excess on the pads.

author: CuriousGeorge
author_rank: Newbie
timestamp: September 10, 2018, 03:06:55 pm
content: Thank you so much guys. I also don't think it got underneat the IC I will do what you guys suggested. Thanks to you guys, it feels like there's light at the end of the tunnel.

author: ArthurDent
author_rank: Super Contributor
timestamp: September 10, 2018, 03:22:18 pm
content: The smaller blob on the lower left seems to be across an unpopulated area so that shouldn't be too bad because there are no parts that will get disturbed when you clean it up plus that solder splatter might not have adhered much to the pads.The large blob seems to have landed mainly on a 60? pin chip that might be leadless, can't tell from the photo. I would carefully cut through the solder around the outline of the chip then you can remove the biggest part of the blob that covers the ceramic top of the chip. That will leave you 4 smaller areas to try to clean without damaging or removing small parts. A couple of these remaining globs might be subdivided by careful cutting to further simplify removal of glob pieces.If the soldered reflowed the solder holding the small parts onto the board you might have to carefully remelt the solder and remove the smaller parts at the same time, remembering exactly where they go, then replacing them after you've cleaned the excess solder off the pads. If you're really lucky the solder didn't melt and bond much of the solder holding the small parts on and you can carefully lift it off. The solder 'probably' didn't go under the chip.It's easy for the rest of us to tell you what might work because it isn't our board. Good luck!

author: Specmaster
author_rank: Super Contributor
timestamp: September 10, 2018, 03:37:14 pm
content: Personally, I'd use a decent desoldering gun and start with IC clearing away small sections at a time from the top of it and then as you approach legs, just take my time and slowly suck away any excess solder and continue this across the board treating each small section in the same manner.I don't think I'd use any kind of a knife or try and pry away the solder or otherwise you run the serious risk of destroying the board for ever but if the treat each part as a mini project, then as you reach the point of the normal solder joint treat it very carefully each time to ensure the item remain soldered as it should be with no short circuits left in place.Yes it will mean a lot of emptying of the desolder gun but its the only way I believe that this type of repair job can be tackled as you will be able control it much better with a small of area molten solder to remove each time by vacuum pump so as not to actively desolder and thus lose any parts in the process.

author: grumpydoc
author_rank: Super Contributor
timestamp: September 10, 2018, 03:42:12 pm
content: Quote from: nanofrog on September 10, 2018, 01:40:08 pmThat would be my 1st questionTry lifting gently - a dental pick would be ideal but a sharp cocktail stick or similar would do at a pinch.

author: CuriousGeorge
author_rank: Newbie
timestamp: September 10, 2018, 08:20:57 pm
content: Getting under it with a sharp razor blade did it well. For parts that were a little tougher I was able to slowly cut back and forth with the razor to be able to lift it up. It pretty much stayed intact and was much less of an issue than I thought it would be. Again, I appreciate all the advice everyone gave, it was very helpful. Thanks guys.