Obtaining Copper Sheet fur use as Pad, Trace Repair on PCB's - Page 1
Forum section: electronics / projects

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: February 24, 2022, 03:57:53 pm
content: What do you use when you do a repair on a PCB with regard to Copper?Most of the Copper Tapes available have adhesive on one side. But when you are doing a proper epoxy repair, you don't want the adhesive. It can be removed with chemicals but that's counter productive and messy.I use CW2500. It is sold as a Conformal coating, but also works to adhere fresh copper pads to PCB. It's rated to over 300F.Where do you get (non adhesive) copper sheet stockthat you can cut pieces out of for repairing PCB pads and larger copper filled areas that are damaged?What thickness do you normally use? Of course it depends on the current through the particular section but something like .4mm would cover a large number of situations. It seldom hurts to have too much current capacity....only too little.Thanks

author: bdunham7
author_rank: Super Contributor
timestamp: February 24, 2022, 04:50:35 pm
content: Look for copper shim stock. Unless you need it very thin for some reason, it is a bit easier to work with if you get it somewhat thicker than a typical PCB trace. .004-.005" perhaps.

author: TimFox
author_rank: Super Contributor
timestamp: February 24, 2022, 05:04:22 pm
content: Also, copper "flashing" for roofing is readily available in 3-oz thickness (compared to 0.5 to 2 oz that is typical for PCBs), but in relatively large rolls.3M also makes an adhesive copper tape with conductive adhesive:https://www.3m.com/3M/en_US/p/d/b40067945/that may work for you.

author: edpalmer42
author_rank: Super Contributor
timestamp: February 24, 2022, 05:05:43 pm
content: You used to be able to buy it at crafts stores to use for copper tooling art projects. There were kits, molds, etc. Copper has become so expensive and copper tooling has fallen from favor so I don't know if that's still available. You might be able to substitute brass strips, but I don't know if that's any easier or cheaper to find.Ed

author: jpanhalt
author_rank: Super Contributor
timestamp: February 24, 2022, 05:15:42 pm
content: Circuit Medic carries 0.002" foil in various widths:https://www.circuitmedic.com/cgi-bin/web2/search.cgiMcMasrer Carr has copper foil down to 0.001"https://www.mcmaster.com/foils/

author: coppercone2
author_rank: Super Contributor
timestamp: February 25, 2022, 06:39:14 am
content: you use thermal adhesive typically, i.e. pace tools cir-kit trace repair kit, used with lapflow tool.Maybe JB weld would be good since it resists temperature well when you solder.

author: jpanhalt
author_rank: Super Contributor
timestamp: February 25, 2022, 09:19:07 am
content: It occurred to me later that you have not said how much you need or what you have to cut it with. Depending on what you do to cut narrow strips, they will curl and work harden.Another option I have done for small repairs is just to peel what I need from a piece of junk board.

author: coppercone2
author_rank: Super Contributor
timestamp: February 25, 2022, 04:47:15 pm
content: You can anneal the copper by heating it to visibly hot (red+) and rolling it with a bakers rolling pin after dunking it ice water to shock the surface oxidation mostly off, then finish with a scotch brite pad or sand paper. I recommend a pen torch or holding it in a gas burner if you have a BBQ or gas stove in a pair of tweezers.You can try making thin strips using sheet metal cutters or scissors if its thin enough, if you cut carefully you can make a nice thin strip no problem. You can probobly also burn the glue off copper tape so long you don't mind the scrubbing afterwards.. get a block of wood to pin the copper down then do 'drag' motions on the copper to clean up the burned stuff when its on a table. The top of the copper strip will be anchored to the wood so you can draw the abrasive over it to clean it up without wrinkling it, and it will be flat since its under strain from the abrasive (hold taught and firm on the surface of your cleaning board). Very sharp abrasive would be best here (silicon carbide sand paper). This would probobly be possible to do on something very small.You can also try to heat up copper wire and flatten it out with a hammer, reheating it ever so often, to make a strip conductor.

author: ThermallyFrigid
author_rank: Frequent Contributor
timestamp: March 21, 2022, 01:30:30 am
content: Thanks for the assists.I ended up using a mix of .250mm conductive adhesive backed tape and some .2mm copper foil sheet and PCB board 2 part epoxy.Seems to have worked well so far.

author: Bravo
author_rank: Contributor
timestamp: March 21, 2022, 12:42:01 pm
content: The Pace company that makes soldering irons, makes PCB track repair parts in the form of pads with tracks coming off them in a multitude of sizes. They also make eylets to anchor the pads to the board. This stuff is quite expensive from our local dealer here in New Zealand. Pace is made in USA so it will be cheaper there. If you are repairing expensive boards, you can justify the cost.

author: all_repair
author_rank: Frequent Contributor
timestamp: March 21, 2022, 12:51:42 pm
content: Savage from another PCB.