This thing about printed circuits

[Norm]

   As some of you know I have been connecting a

couple of wires to some calculators,

 a parallel switch to the ='s button switch.

  Things worked fine with the conductive ink

printed circuits, a simple matter of taping a

bared wire across the specific part of the printed circuit.

  Now a regular printed circuit...copper etched

circuit...it doesn't seem to work, of course I

scraped the protective coating off down to bare

shiny copper, the line is about .030 wide, Put 2

small holes on each side of the line about like this ..

the lead wire is on the back with the

bare end poked thru one hole and looped over

the bar and poked back into the other hole just

putting a little square of tape doesn't make

good contact.

  I notice that where a bridge across some bus

bars is require they just paint it on with some

type of conductive black paint...can you buy

this stuff somewhere or should I learn how to

solder printed circuits?

  My couple of attempts at soldering printed circuits

were a dismal failure, I use the right

type of solder and flux from RatShak but I

suspect that having a cheap pencil iron with

uncontrolled heat probably goofed me up

....thinking putting a slight dab of flux on the

iron and as soon as it starts to smoke...

unplug it and solder a joint before it cools off?

   Okay guys...can you help?

      Thanks a lot!

              ( :>) Norm.

[TomW]

Norm;

Try this trick:

Take your soldering iron tin the tip well then tin the wire you want to attach. Now lay that wire down on the [very clean and shiny] circuit trace. press the wire down with a screwdriver or other tool. very carefully put the tip of the iron on the wire above where it contacts the trace as soon as you see the solder go liquid remove the iron while holding the wire steady with the tool.

This works quite well for me and does not put excess heat on the trace on the board.

Once soldered you should glue across the connection to keep from pulling the trace up from the board.

Cheers.

TomW

[thunderhead]

If you're going to solder printed circuit boards at all regularly, get a temperature-controlled soldering iron.  The cheap Antex ones are OK, if they have a reasonably fine bit - you don't need to spend lots of money on a solder-station.

The other tool that will help a lot is a "solder sucker" - I use the sort that is like a sort of spring loaded hypodermic in reverse.  Too much solder is as bad as too little.

Conductive paint is available from electronics shops, too.  I've had plenty of success with it, except repairing flexible circuits: it always ends up cracking where the flexing cracked the original copper. :-(

[ghurd]

I taught quite a few people to solder.

Nobody wants to get the parts hot enough.

Did the solder 'ball up'?  The parts are not hot enough.

The parts (wire and board) need to be hot enough to melt the solder.

Let the iron get hot.

Melt an inch or 2 of solder on it,

When the smoke stops, wipe off the solder and black crud.

Go instantly to the waiting board and wire.

Don't heat the solder.

Heat the wire and board for about 1 second.

Then add solder from the side.

Then get the iron away.

The iron, wire and board melt the solder.

It won't take long. Thats small stuff.

It won't take much on that. 1/8"?

Cut the first inch of solder off before you start.

(the flux probably ran out)

Pinch the end when you are done.

If the solder bridges to the next part,

let it cool, touch the iron on the solder bridge.

Enough usually sticks to the iron to clean it up.

The wire's insulation on the caculator don't feel like they will take a lot of heat.

It is going to be a bit of balancing act to get the wire hot enough,

without melting the insulation.

And Norm,

Didn't get the big monster apart yet. Too cold.

Have to go out of town for a few.

But as soon as I get back...

G-

[Norm]

  Well I learned what a trace is and I learned

how to solder those wires on,then on the back

of the board where the wires pokes into the hole

I put a drop of hot glueon each...that should hold it!

  Thanks for the tip Tom! It almost looks like an original

 part of the circuit!

  Next part of the circuit, I was thinking of salvaging

one of the opti-interupters from a

mouse to operate this circuit instead of a

direct or magnetic reed  switch.

  I bet there is all I need right there, I've

already used some of the wire for this circuit

that I just soldered.

                    Fun !

                    ( :>) Norm.

[Norm]

  Oh..Oh...sounds like you're talking a more

expensive iron than the one I got at WallMart

for $2.95? LOL

  Yeah I used to have one of those rubber bulb

type solder suckers (they do come in handy for scrounging parts from remotes and mouses (mice?)...didn't realize they had something better!

  and the part about the conductive paint is

also helpful!

                Thanks a lot for

                your help.

                  ( :>) Norm.

[Norm]

   Thanks for the comment G, actually I was

using too much heat. I think a couple more

calculators and I'll be getting the hang of

it...funny how the more I do these things

the easier it gets...the calculator I gave you

had a plastic sheet with a conductive paint

printed circuit. all I had to do was tape a

couple of wires across the traces.

  Have you used it like for a coil counter yet?

   You might not have noticed that little Briggs

from a reel-type motor? or the Tach hanging on

the wall? Well...I'm getting ready to hook those

up to that little motor with the square base, and

what it puts out at various speeds, so I'll

know what size prop and wind I'll need.

              catch ya later!

                ( :>) Norm.

[ghurd]

Have not got the next coils figured out yet.

Half my 'part' parts are in a different place.

I think I got 150ma through a diode into a 13.2V battery, at 600rpm?

The Zub-Woofer you have would surely work.

I have the little conversion, big battery, test wires, etc. all over the kitchen.

Both coil sets connected in parallel.

A good 650rpm, 12.7V battery, 0.32A.

A little lower than 650rpm, 14.0V battery, 0.29A.

The drill was charging the test battery.

Cut in at about 120~150rpm with 0.03A,

I'm sure that is only the coil with 3X the turns of the other.

I think it would be better for a 24 or 48V system.

The blade design is still giving me fits.

When 1 set of tested number lines up, NONE of the others are even close!

Probably because the coil resistance is sooo high, and 2 sets of coils acting differently.

Or because I didn't test the coils seperately and they are very different.

Probably overthinking it again. I always do.

I should just hang a 3 blade, 24" Zub-Woofer on it and see.

Maybe I can get the wife to do that while I'm gone?  hehehe.

G-

[Norm]

   Don't it just get you sometimes ....just

when you're making some real progress

the wife wants you to clear off the table

all of a sudden ..#1 priority is suppertime!

   Just don't seem to understand your about

to make a major breakthu in RE!

   Ah...Well I think we might have died from

malnutrition a long time ago if it wasn't for them!

Right?

                 Havin' Fun!

                   Norm.

[wphfla]

Just a comment from the peanut gallery.  I've used super-glue to repair wiring breaks on printed circuit boards.

wphfla

[thunderhead]

Yes it is a bit more expensive - maybe £20 or so.  But I cannot find one for sale online that is not 240v, which I guess might be no good for you.

The rubber bulb solder suckers work too, although they are more fiddly.  With the spring-loaded ones, you just press a little button on the side.

I tend to spend money on tools: my father taught me to pick the best, not the cheapest - as when the cheapest breaks in the middle of the job, you still need to buy the best.

That doesn't mean I bought a £250 solder-station, but I get the extra feature - temperature control - for something between the two.  But my degree is in electronics and computer science - being able to solder well is part of my trade.

For the same reason I've bought lots of secondhand test equipment that was the leading edge a few years ago.  The equipment is still good - the laws of physics haven't changed in the last 20 years - it just has dials and switches instead of computer graphics on the front.

[Norm]

   Thanks W, The stuff is conductive or you

glue conductive material across the break?

   Please go into further detail for example,

I like to hear stories, I'm listening, I

know the feeling when you try to tell somebody

something and they're saying like 'Oh Yeah  I

tried that once ...it didn't work out very well'

, but then they don't tell me why it didn't or

that they found something better???

                  so tell me the story...

 even if you might think it's unimportant!

                  Fun!

                   ( :>) Norm.

[Psycogeek]

ya what he said.

and on FLUX in the solder, its in the middle of the solder.

flux seems to work best when its HOT before its BURNED,

like right before it burns it cleans de-oxidises best.

so if you put solder on the tip first, then move it to the part

which is an effective method for some things and tight spots and all

dont burn up the flow flux junk before it gets to what you want

to clean with it.

the smoke rolling off is the flux toasting into uselessness

(of course it isnt lead vaporizing :-)

that is why (if you can fit it in) putting the solder on the

HEATED parts, it flows , and cleans and allows the solder to stick.

and that is why some people find the TINY solder guage to be much better

the tiny stuff is better even for the bigger stuf, when it comes to

fluxing the area for you.

you get flux in there with the solder, wihtout having 2lbs of lead there.

what your doing is smaller than i would want to work, without

Magnifying light

controlled solder thing

small solder.

But then i will avoid SMT (SMP or whatever they call it) parts

whenever possible :-)