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

[Mr. Land]

Hi folks,

I was wondering if I could solicit opinions/experience with the use of
silver paints/pens for repairing broken PC traces.

I have a board that was cracked completely in half and all of the
traces were broken, too. There are many of them and they are quite
small. I attempt fine wire/solder repair but that wasn't going too
well.

I am considering trying to use either silver paint w/fine applicator
brush or a silver paint pen to try to repair the traces across the
crack (I have already physically repaired the crack itself.

Thanks very much.

 

[N Cook]

Hi folks,

I was wondering if I could solicit opinions/experience with the use of
silver paints/pens for repairing broken PC traces.

I have a board that was cracked completely in half and all of the
traces were broken, too. There are many of them and they are quite
small. I attempt fine wire/solder repair but that wasn't going too
well.

I am considering trying to use either silver paint w/fine applicator
brush or a silver paint pen to try to repair the traces across the
crack (I have already physically repaired the crack itself.

Thanks very much.

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.

 

[Mr. Land]

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.

That scalpel technique sounds like a great idea.

Thank you.

 

[Allodoxaphobia]

That scalpel technique sounds like a great idea.

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

 

[mike]

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...

 

[Marra]

I would just solder wires across the gaps.

 

[Matt J. McCullar]

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.

 

[Jim Yanik]

Hi folks,

I was wondering if I could solicit opinions/experience with the use of
silver paints/pens for repairing broken PC traces.

I have a board that was cracked completely in half and all of the
traces were broken, too. There are many of them and they are quite
small. I attempt fine wire/solder repair but that wasn't going too
well.

I am considering trying to use either silver paint w/fine applicator
brush or a silver paint pen to try to repair the traces across the
crack (I have already physically repaired the crack itself.

Thanks very much.

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

 

[Mr. Land]

[email protected]:








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

--
Jim Yanik
jyanik
at
kua.net

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.

 

[Smitty Two]

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?

Not sure why you see that as advantageous to mechanically stripped wire,
but some magnet wire has thermal insulation that melts when soldered.
(We buy magnet wire from MWS.)

You might also use some very fine buss wire, or consider taking
individual strands from 26 AWG stranded wire (around 42 AWG IIRC), which
is what we use for very small conductors. Then a dot of epoxy or RTV
here and there, or a shot of conformal coating from a spray can will
keep them from shorting to one another if need be.

 

[Ron(UK)]

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?

You probably mean this, which is what I use.

http://www.rrunner.co.uk/wire/bobbins.htm


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.


http://www.rrunner.co.uk/pens/pens.htm

Ron(UK)

 

[Ken G.]

No . the paint will get hard & crack

 

[Andy Cuffe]

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.

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

[email protected]

 

[msg]

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

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

Michael

 

[whit3rd]

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.

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).

 

[Fergus McMenemie]

I was wondering if I could solicit opinions/experience with the use of
silver paints/pens for repairing broken PC traces.

I have a board that was cracked completely in half and all of the
traces were broken, too. There are many of them and they are quite
small. I attempt fine wire/solder repair but that wasn't going too
well.

I am considering trying to use either silver paint w/fine applicator
brush or a silver paint pen to try to repair the traces across the
crack (I have already physically repaired the crack itself.

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......