"Glue" for lifted traces on PCB ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: September 11, 2018, 03:09:52 pm
content: I'm working on a PSU and the mains power comes into 2 blade type connectors, and on both of them, the blades, solder pools and big copper traces have lifted off around the through holes.It's on a standard single sided fiberglass PCB. What kind of glue or epoxy or whatever is used to fix that ? (If I wanted to restore properly rather than cutting off the blades/loose trace area)

author: chemelec
author_rank: Contributor
timestamp: September 11, 2018, 04:28:48 pm
content: Can You show a Picture of this?

author: james_s
author_rank: Super Contributor
timestamp: September 11, 2018, 04:45:26 pm
content: I've had some luck using ordinary superglue, although it will release if you get it too hot usually it will hold well enough to solder the part which then tends to hold down the trace.

author: SeanB
author_rank: Super Contributor
timestamp: September 11, 2018, 06:12:01 pm
content: Superglue to hold the traces down, and add strain relief as the superglue bond is not going to survive flexing and stress, which is what lifted them off in the first place. solve the stress and the glue will hold them in place.

author: particleman
author_rank: Regular Contributor
timestamp: September 12, 2018, 01:24:15 am
content: This is what I use.https://www.digikey.com/product-detail/en/chemtronics/CW2500/CW2500-ND/1929217It says overcoat but it works well as and undercoating and holds up to iron temps as long as you aren't going crazy.

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 12, 2018, 01:30:36 am
content: Quote from: SeanB on September 11, 2018, 06:12:01 pmI think superglue breaks down over a certain temperature. This property is used to solidly yet temporarily keep things in place while machining

author: Sceadwian
author_rank: Unknown
timestamp: September 12, 2018, 01:55:14 am
content: I'd be more worried about what caused it rather than fixing it. Traces don't typically lift just on a lark. Pictures really would help here.

author: t1d
author_rank: Super Contributor
timestamp: September 12, 2018, 02:20:45 am
content: There are really good videos, on YouTube, as to how to do this type of repair... Both for just making it work (scraping a trace and bodging on a wire) and conservation/restoration techniques, for collectible electronics. Sounds like you are interested, in the latter. There are even expert level soldering tutorials, by NASA... No kidding.

author: Ian.M
author_rank: Super Contributor
timestamp: September 12, 2018, 04:47:41 am
content: Not surprisingly, the Chemtronics product Particleman mentioned is a high temperature two part epoxy. Its temperature specs are:QuoteUnfortunately, like most epoxies it looses strength below 100°C, but as many soften enough to easily be removed by a scraper around that temperature and it has short-term resistance up to 315°C, its far more suitable for holding pads that will be soldered than typical hardware store epoxies, which tend to melt forming a soft goo that allows pads to skid out of place when you try to solder them.Cured Cyanoacrylate adhesives (superglue) tend to fail by depolymerisation at temperatures in the range 140°–180°C. The resulting monomer is rather volatile so boils out from under the pad well below soldering temperatures, and the fumes are extremely noxious. Therefore the use of generic superglue for pad repair before soldering is dubious at best. Specialist high temperature Cyanoacrylate adhesives may do a little better, but you'll have great difficulty finding any that can withstand greater than 200°C, so soldering pads is still problematc. The use of thin superglue to reinforce a loose pad after soldering is only likely to be successful if you have an ultrasonic cleaning tank for flux removal, as even a thin film of flux under the loose pad will prevent any chance of a reliable bond.

author: lordvader88
author_rank: Frequent Contributor
timestamp: September 12, 2018, 05:21:35 pm
content: Quote from: Sceadwian on September 12, 2018, 01:55:14 amWell it's inside a computer PSU. The mains goes to some of the EMI filters on a little PCB, then into the main PCB via the blade connectors. So it should never move at all really. So either the factory worker broke it, or someone else was in there later and did it. Pretty sure I didn't do it taking the connector off, that would be pulling it tighter taking it off, not pushing them on.I think it's the 1st tho, there's a few other pads right where stuff comes through the PCB that have lifted a bit too. IDK tho, 1 corner of the PCB where the output cables attach, seems a bit warped. That shouldn't be either.This PSU cycles on/off/on/off, I haven't figured out why yet.I might order an Andostar 301 this week, or I might get cheap diff. probes, or I might get a new GPU. So no pictures yet.

author: Zero999
author_rank: Super Contributor
timestamp: September 14, 2018, 02:09:44 pm
content: I have in the past superglued PCB traces down and soldered them. It's true the glue doesn't survive soldering, but it's enough to keep things in place for long enough to solder, just be quick. Once the parts are soldered, quickly clean it and use more glue to fix the tracks back don. Obviously use a fan to suck the smoke away, as the fumes are toxic.Having said all of the above, I wouldn't recommend it, although it works, it can be messy. I'd glue the components in place and replace the track with bodge wires.

author: particleman
author_rank: Regular Contributor
timestamp: September 14, 2018, 03:29:29 pm
content: This is a repair I did last night. The pad and trace were totally lifted.

author: tkamiya
author_rank: Super Contributor
timestamp: September 14, 2018, 10:57:16 pm
content: As far as I know, once the trace lifts or gets damaged, there is really no way to make it right again. The best you can do is whatever the situation calls for. Superglue is nice and handy. None of glues tolerate heat very well, so if you need to repair that section again, glue will burn. It also depends on size and purpose of the section that were damaged. Sometimes, cutting that off and using a short jumper wire is appropriate.I don't thing there is such thing as a universal best here.

author: Ian.M
author_rank: Super Contributor
timestamp: September 15, 2018, 02:23:30 am
content: There is nothing magical about FR4 and other epoxy/glassfibre PCB repair (I am specifically excluding cheap SRBP and exotic substrates).Consider an ordinary FR4 or similar PCB. Thin copper foil was originally bonded to the epoxy laminate by chemically treating it to get a highly adherent porous oxide layer then applying heat and pressure causing a partially cured epoxy surface to flow into the pores, and thermo-set forming a mechanical and chemical bond between the base lamiate and the foil.With the right materials and appropriate surface preparation of both the substrate and the foil its possible to epoxy bond a track or pad repair that's *NEARLY* as good as the original foil to substrate bond. The only differences are the difficulty of applying heat and pressure to get a fully cured bond, and the slightly poorer adhesion bonding to a fully cured substrate.However, in most cases it just isn't economic to do a milspec quality board repair, as the full repair process is too slow, needs too much highly skilled hand labour, and the tools and materials required to do it properly aren't cheap enough to make it worth having them available for one-off or occasional use.With consumer goods, the average repair shop therefore does the best they can quickly, with easily available tools and materials, and rejecting jobs which require too extensive board repairs relative to the replacement cost of the populated board.