How well do silver paints/pens fare at trace repair?

For fine trace bridge-wiring you have to stagger the lands on each side of the break to give soldering room.

If you try paint, reinforce the board wherever is free from traces, clean as best, paint over the whole relevant area, let solidify, and then with a razor blade/ scalpel and small straight edge, cut into the paint between the traces.

-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on

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That scalpel technique sounds like a great idea.

Thank you.

Ya, but.... The OP's problem was/is a _cracked_ PCB. I fear the conductive paint will wick down into the crack and migrate every which-a-way.

GL Jonesy

Second that. I tried to repair a damaged trace on a PDA touch screen. Got overzealous with the silver paint and it wicked all the way to the center of the screen between the touch surface and the display glass. Bummer...

I would just solder wires across the gaps.

So would I. If it flexed once, it will flex again. Soldered wires have much more "give" than paint.

"Mr. Land" wrote in news:5a87d396-034e-4360-a92f- snipped-for-privacy@i29g2000prf.googlegroups.com:

consider that a cracked trace was caused by board flex;why would PAINT be any better at staying connected?

It's not that the traces cracked due to excessive flex of the board - it's that the entire board was physically broken in half (I suppose you could say, due to _extreme_ flex!)

I physically repaired the board by using Gorilla glue - that glue completely filled in any gaps along the crack (and oozed out along the component side, which is OK with me, just extra strength as I see it.) So there doesn't seem to be any danger of the silver paint oozing down below the surface of the board and making undesirable paths.

Anyway, I picked up a silver applicator pen today and gave this a try

- alas, even with the pen, the paint is too hard to control to repair these fine traces.

I guess I'll go with point-to-point wiring. And since that's been brought up %^)...

Years ago I did some wire wrapping prototypes, and the wrapping wire I had at that time was very fine (sorry, can't state the exact gauge), and it had a coated insulation that burned away with a soldering iron (in other words, no stripping necessary.) It seems like this would be ideal to use for this repair - only I can't seem to find anything like this on the 'net.

Anyone heard of this stuff/seen it anywhere?

Thanks very much folks, for all the great advice.

You probably mean this, which is what I use.

It`s called prototyping wire, you can get a tool which makes it easier to handle, or if you're cheap like me, make your own out of an old biro.

Ron(UK)

No . the paint will get hard & crack

That's exactly what I use for circuit board repair. It is still available, but it's been a while since I bought any. Andy Cuffe

snipped-for-privacy@gmail.com

Search for 30ga. Kynar (sorry to non-U.S. readers, only know domestic spec.)

Michael

Beldsol wire, from Belden; it needs a hot (over 700 F) iron to work, came in a prototyping kit in a couple of different gages (the kit was Vector brand, as I recall).

Yep. I have actually done this, during IC debug and test, to patch two points on a single die together. After scraping through the glass or oxide. this was in the days of 3u devices!

The trick was to get silver paint with a high enough silver content in it. After lots of phoning around we were told to visit the local ford dealer and use the paint they use to repair the rear window demisters in ford cars. This was over ten years ago......