Strange flex cable traces material?

[frenky]

I'm trying to fix a pump controller for a friends friend.   

There was a shorted voltage regulator that I have already fixed and the only thing left to repair is teared flex cable.

Traces are sandwiched between two layers of plastic foil. So I peeled top layer off.

Traces are made from some kind of silver sparkly stuff...
I tried soldering it but the traces just turned grey and solder did not stick to it.

Anybody has an idea how to solder to it or fix it in some other way?

Tnx.

[Twoflower]

You might try some electrical conductive glue/colour (something like LOCTITE® 3863) to repair the flexcable. Probably even teh manufacturer used such material to print the wires on the foil.

[frenky]

Thank you for a good advice.

[Kilrah]

Ugh, these things are awful. Super fragile and a PITA to repair.

[mikeselectricstuff]

It's printed silver ink. May be fixable using silver paint or epoxy. You won't solder to it.

[Twoflower]

Actually the more time I'm thinking of it, the more sceptical I get with my own suggestion.

As the tape moves the connection will break immediately. At least you need to do something in addition to either prevent movement in the defective area. Or adding some thin copper wires bridging the crack and glue them with the stuff and probably stiffen the area as well.

[RobK_NL]

There are special pens available with which you can redraw the broken lines.

http://nl.farnell.com/chemtronics/cw2900/flex-conductive-pen/dp/1663188

Ridiculously expensive stuff, but it works.

[frenky]

Thank you guys!

I have just ordered a few of these:
https://m.aliexpress.com/search.htm?keywords=silver%20conductive%20glue&sortType=TC_D&shippingCountry=SI&viewtype=1

I will put bare copper wire over the crack on each line and glue it with this silver glue.
That should conduct ok.

Then I'll put a blob of epoxy on the top and bottom for better strength.
The cable is only moved when opening the case so hopefuly it will last.

Tnx again.