Homebrew PCBs

I've gotten some breakout boards in the past from Sparkfun that worked well 
for SOIC but I now need a few for a uSOIC which has 0.5mm lead pitch for 10 
pins (or more.)

Any suggestions?

73

jim ab3cv

"Jim Miller" <jim@...> writes:
> I've gotten some breakout boards in the past from Sparkfun that
> worked well for SOIC but I now need a few for a uSOIC which has
> 0.5mm lead pitch for 10 pins (or more.)

These are the types of boards I'm most likely to make at home.  Just
design one, put four to six copies on a small panel, and etch them.
Choose the best resulting board.  I use resistor lead trimmings for
"legs" (they're smaller than 0.025" sq posts).

0.5mm pitch is only 10 mil rules, you should be able to do that at
home.

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:
>
> 
> "Jim Miller" <jim@...> writes:
> > I've gotten some breakout boards in the past from Sparkfun that
> > worked well for SOIC but I now need a few for a uSOIC which has
> > 0.5mm lead pitch for 10 pins (or more.)
> 
> These are the types of boards I'm most likely to make at home.  Just
> design one, put four to six copies on a small panel, and etch them.
> Choose the best resulting board.  I use resistor lead trimmings for
> "legs" (they're smaller than 0.025" sq posts).
> 
> 0.5mm pitch is only 10 mil rules, you should be able to do that at
> home.
>

I agree with DJ - Do a panel of them to make sure you get a good one 
if you are not always doing stuff that small.

I have just done a 0.45mm QFN package (ATMega48) and the resist came 
out good.  The etch is what I had a problem with.  I panelised 15 
boards to make sure I got a good one.  

Some tracks (6-8 thou) almost got etched completly away on one side 
of the panel before the other side was clear of copper.

I guess it is dinfitly a case of some people have got bubble etchers 
that work well and mine is crap :D

I think I am going to keep a tub of Ferric Chloride around just to do 
these fine ones and float etch them till I get a spray happening.

----- Original Message ----- 

From: "Andrew" <andrewm1973@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, August 17, 2007 10:56 PM
Subject: [Homebrew_PCBs] Re: 0.5mm pitch breakout board?


>
> I agree with DJ - Do a panel of them to make sure you get a good one
> if you are not always doing stuff that small.
>
> I have just done a 0.45mm QFN package (ATMega48) and the resist came
> out good.  The etch is what I had a problem with.  I panelised 15
> boards to make sure I got a good one.
>
> Some tracks (6-8 thou) almost got etched completly away on one side
> of the panel before the other side was clear of copper.
>
> I guess it is dinfitly a case of some people have got bubble etchers
> that work well and mine is crap :D
>
> I think I am going to keep a tub of Ferric Chloride around just to do
> these fine ones and float etch them till I get a spray happening.

I've done one or two single-sided QFN boards for accelerometers, I find it 
best to make one at a time.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND and FT-857D transceivers
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller

"Andrew" <andrewm1973@...> writes:
> Some tracks (6-8 thou) almost got etched completly away on one side
> of the panel before the other side was clear of copper.

Have you tried the sponge-wipe method?  I've found I can manually
control the etch progress that way, so it all comes out even.

> "Andrew" <andrewm1973@...> writes:
> > Some tracks (6-8 thou) almost got etched completly
> > away on one side of the panel before the other
> > side was clear of copper.

> DJ Delorie wrote:
> Have you tried the sponge-wipe method?  I've found I
> can manually control the etch progress that way, so
> it all comes out even.

I have not yet.  I am scared that the little ~6 thou
tracks will get scratched.

I will give it a go on a board with 10-12 thou tracks
to see how it goes though.

> Leon wrote:
> I've done one or two single-sided QFN boards for
> accelerometers, I find it best to make one at a
> time.

Leon,

How do you hold your boards one at a time ?

I just use the clips that came with the etch tank
(Which BTW are over twice the size of the PCB). 
If I try use them with a board that is too small
and can float around they end up one side up and
one down in the bubble flow and one side gets 
over etched.

I use 4 sided leadless packages all the time for
the AVR CPUs and normally dont have an issue
because they normally have a 0.5mm lead pitch.
With the 0.5mm lead pitch I can use 8-10 thou
tracks.

The one I am using for a current project is a
QFN28-4 that has a 0.45mm lead pitch.  I have
droped down to 6-8 thou tracks which seems to
be my etching limit with CuCl.

"Andrew" <andrewm1973@...> writes:
> I have not yet.  I am scared that the little ~6 thou
> tracks will get scratched.

Pulsar does recommend the TRF layer to protect the toner if you're
going to use a sponge.  It's a thin film that sticks to the toner to
seal it and add some physical protection as well.  Perhaps a test
board would be useful?  I've got one here I use for such things:

        http://www.delorie.com/pcb/

scroll down to "Goodies" and download the bloat test board (pcb, pdf,
gerber).  It's got various traces and spacing, plus various annulus
sizes, from 12 mils down to 1.

> > "Andrew" <andrewm1973@...> writes:
> > I have not yet.  I am scared that the little ~6
> > thou tracks will get scratched.

> DJ Delorie wrote:
> Pulsar does recommend the TRF layer to protect the
> toner if you're going to use a sponge.  It's a
> thin film that sticks to the toner to seal it and
> add some physical protection as well.

Probably won't help me as I am one of those photo
zealots.

I think until I get spray etching happening I will
just stick to Ferric Chloride on boards with <8 thou
dimensions.  The CuCl just undercuts more from
my expereince.

> Perhaps a test board would be useful?  I've got
> one here I use for such things:
>         http://www.delorie.com/pcb/
> scroll down to "Goodies" and download the bloat
> test board (pcb, pdf, gerber).  It's got various
> traces and spacing, plus various annulus sizes,
> from 12 mils down to 1.

Thanks - Will have a look at the bloat plugin.

I only just converted to gEDA/PCB last week and
am only just getting up to speed on it and learing
how to draw footprints and symbols at present.
(And I will probably be one of the people you
scream at for doing heavy symbols)

Going to give your teardrop plugin a go as soon as
I have drawn a real PCB.

http://www.thehacktory.com/Simple-IR-RX-Prototype-V1p4-Top.jpg

Is a picture of the final ever board I will
draw with old protel for DOS.  Down at this 
size the imperial back end that only went to
1000ths made things frustrating.  All the traces
and clearances should have been 0.2mm but the SW
randomly made them about 6 or 7thou on print out.

The three packages shown are

A SC75-6 package with 0.5mm pitch (easy)
A Motor driver in a DFN10 with 0.5mm pitch (easy)
ATMega48 in a QFN28_4_EP that has 0.45mm pitch

That last 0.05mm makes a difference.

Personally, I've had exceptional results using the sponge method with
Ferric Chloride on both toner transfer (with the TRF layer) and
photo-resist.  In fact I consistently get better results with
photo-resist than w/ toner.  As long as I'm paying attention I get
very little if any undercutting.  Just my 2 cents.

--- In Homebrew_PCBs@yahoogroups.com, "Andrew" <andrewm1973@...> wrote:

>
> 
> > > "Andrew" <andrewm1973@> writes:
> > > I have not yet.  I am scared that the little ~6
> > > thou tracks will get scratched.
> 
> > DJ Delorie wrote:
> > Pulsar does recommend the TRF layer to protect the
> > toner if you're going to use a sponge.  It's a
> > thin film that sticks to the toner to seal it and
> > add some physical protection as well.
> 
> Probably won't help me as I am one of those photo
> zealots.
> 
> I think until I get spray etching happening I will
> just stick to Ferric Chloride on boards with <8 thou
> dimensions.  The CuCl just undercuts more from
> my expereince.
> 
> > Perhaps a test board would be useful?  I've got
> > one here I use for such things:
> >         http://www.delorie.com/pcb/
> > scroll down to "Goodies" and download the bloat
> > test board (pcb, pdf, gerber).  It's got various
> > traces and spacing, plus various annulus sizes,
> > from 12 mils down to 1.
> 
> Thanks - Will have a look at the bloat plugin.
> 
> I only just converted to gEDA/PCB last week and
> am only just getting up to speed on it and learing
> how to draw footprints and symbols at present.
> (And I will probably be one of the people you
> scream at for doing heavy symbols)
> 
> Going to give your teardrop plugin a go as soon as
> I have drawn a real PCB.
> 
> http://www.thehacktory.com/Simple-IR-RX-Prototype-V1p4-Top.jpg
> 
> Is a picture of the final ever board I will
> draw with old protel for DOS.  Down at this 
> size the imperial back end that only went to
> 1000ths made things frustrating.  All the traces
> and clearances should have been 0.2mm but the SW
> randomly made them about 6 or 7thou on print out.
> 
> The three packages shown are
> 
> A SC75-6 package with 0.5mm pitch (easy)
> A Motor driver in a DFN10 with 0.5mm pitch (easy)
> ATMega48 in a QFN28_4_EP that has 0.45mm pitch
> 
> That last 0.05mm makes a difference.
>

"Andrew" <andrewm1973@...> writes:
> I think until I get spray etching happening I will
> just stick to Ferric Chloride on boards with <8 thou
> dimensions.  The CuCl just undercuts more from
> my expereince.

Another thing is to try 1/2 oz copper - half the undercutting, half
the etch time, etc.

> (And I will probably be one of the people you
> scream at for doing heavy symbols)

Not me :-)

> Going to give your teardrop plugin a go as soon as
> I have drawn a real PCB.

I found that useful for hand-etched, in case the drills are off.

> Down at this size the imperial back end that only went to 1000ths
> made things frustrating.

We changed PCB from 0.001" to 0.000010" resolution for similar
reasons.

> That last 0.05mm makes a difference.

See http://www.delorie.com/pcb/first.html for a 0.4mm pitch part,
hand-etched with 1/2 oz TT, with 01005 caps.

----- Original Message ----- 

From: "Andrew" <andrewm1973@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, August 18, 2007 1:58 AM
Subject: [Homebrew_PCBs] Re: 0.5mm pitch breakout board?


>> Leon wrote:
>> I've done one or two single-sided QFN boards for
>> accelerometers, I find it best to make one at a
>> time.
>
> Leon,
>
> How do you hold your boards one at a time ?

I don't use an etching tank, just a small plastic container in a larger one 
with some very hot water in it. I agitate by rocking the etchant container 
continuously - 5 mins with fresh FeCl3. I've got a bubble etching tank, but 
I don't like it much.

>
> The one I am using for a current project is a
> QFN28-4 that has a 0.45mm lead pitch.  I have
> droped down to 6-8 thou tracks which seems to
> be my etching limit with CuCl.

That would be more difficult.

How do you solder the QFNs? I use drag soldering, but I have got a very 
sharp point cartridge for my Metcal which might be better.

Leon
--
Leon Heller
Amateur radio call-sign G1HSM
Yaesu FT-817ND and FT-857D transceivers
Suzuki SV1000S motorcycle
leon355@...
http://www.geocities.com/leon_heller

I ordered the sharpest pencil point they make, to try if it is better
than a larger tip for QFN and other small stuff.
It isn't.
I end up drag soldering all the same, and the thin tip is a nightmare
if you try to solder even small pins to big copper areas.
With the slightly rounded tip drag soldering works whatever way you
move the iron. With the sharp pencil tip i find it is better to angle
the tip and push it so that the point is leading. If you let the point
trail it makes more solder bridges. My theory is the trailing fillet
in the gap between tip and PCB aids in cleaning bridges, with the
sharp tip trailing there is no fillet. With larger  rounded chisel
type tips there is always a fillet whichever way you angle the iron.

So you can drag solder with a sharp pencil tip, but there doesn't
actually seem to be any advantage over a slightly larger more
universal tip.

I plan to buy the power well tip some day, and see if it is better in some way.
(It's a little like the hoof from metcal)

ST

On 8/18/07, Leon <leon355@...> wrote:

> How do you solder the QFNs? I use drag soldering, but I have got a very
> sharp point cartridge for my Metcal which might be better.
>
> Leon

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, August 18, 2007 9:37 AM
Subject: Re: [Homebrew_PCBs] Re: 0.5mm pitch breakout board?


>I ordered the sharpest pencil point they make, to try if it is better
> than a larger tip for QFN and other small stuff.
> It isn't.
> I end up drag soldering all the same, and the thin tip is a nightmare
> if you try to solder even small pins to big copper areas.
> With the slightly rounded tip drag soldering works whatever way you
> move the iron. With the sharp pencil tip i find it is better to angle
> the tip and push it so that the point is leading. If you let the point
> trail it makes more solder bridges. My theory is the trailing fillet
> in the gap between tip and PCB aids in cleaning bridges, with the
> sharp tip trailing there is no fillet. With larger  rounded chisel
> type tips there is always a fillet whichever way you angle the iron.
>
> So you can drag solder with a sharp pencil tip, but there doesn't
> actually seem to be any advantage over a slightly larger more
> universal tip.
>
> I plan to buy the power well tip some day, and see if it is better in some 
> way.
> (It's a little like the hoof from metcal)

The mini-hoof doesn't work very well for drag soldering with QFN, I use a 
rounded tip as well for that, with plenty of gel flux. The mini-hoof is very 
good on fine-pitch QFPs, of course.

Leon

> Leon and Stefan wrote:
> [About drag soldering QFNs]

If the chips have legs like TQFPs or
even stubby metal stumps like _some_
QFNs have then you can drag a pool
of solder across the pins and the
surface tension will leave a nice
clean set of legs.

However the QFNs that you can hardly
see the pads on the side of there is
not much choice but to reflow them.
Also anything with an exposed pad
you must reflow.

I have a hot air tool and all the
gear needed to do it properly,
however when I want to do it quick
and dirty I just use a butane torch.
(only on prototypes mind you)

Using the hot air tool you need to
carefully put down paste or better
still use a stencil.

The dodgy butane torch method you
just pre-tin the pads with 60/40,
pre tin the pins on the chip, run
your flux pen across the PCB and
place the chip.

I then place the target PCB on a
scrap of FR4 and preheat from
below for a bit.  I then move the
heat to the top side and very
gently continue the heat.  When I
see the chip move and allign itself
I give it a bit more heat close up
and then back off and let it cool
slowly.

A small off cut of 60/40 sitting on
the scrap PCB can be a good
indicator of progress.  Spend about
20% more time pointing the heat at
it and when you see it melt you know
you are close.

As far as dragging the pool of
solder across anything and having
the surface tension pull the pool to
leave a clean pin - I think the temp
is very important.  Too hot and the
flux burns away, too cold and it is
not liquid enough.  That is the
reason I think that a thicker tip is
better.  The fine needle tips I have
(on a Hakko) just don't get the heat
down the business end fast enough.

I get much better results dragging
the solder away with a tip that is
over a mm than one that is 0.7mm.

Also touching new solder to the pool
very regularly to keep flux in the
game helps me out.

> DJ Delorie wrote:
> <BIG SNIP>
> See http://www.delorie.com/pcb/first.html
>for a 0.4mm pitch part, hand-etched with
> 1/2 oz TT, with 01005 caps.
>

I think 0402s are all the fun I want to have
for now.  I could probably get results with
components 1/2 to 1/3 that size but it would
not be very productive time wise.  I find
the 0402s much much slower than 0805s.

If I wasnt trying to get the weight of that
receiver in the earlier photo down to 1/4
of a gram I would not have used them there
even.

On 8/18/07, Andrew <andrewm1973@...> wrote:
>
> If the chips have legs like TQFPs or
> even stubby metal stumps like _some_
> QFNs have then you can drag a pool
> of solder across the pins and the
> surface tension will leave a nice
> clean set of legs.
>
> However the QFNs that you can hardly
> see the pads on the side of there is
> not much choice but to reflow them.
> Also anything with an exposed pad
> you must reflow.

Yes, you must also reflow if there is a thermal pad. Although there is
a method to pre-tin the pad, the reflow it, and then drag solder the
surrounding pads. It is suggested for rework this way by one
manufacturer of QFN cases, i don't remember the name. This will work
well when you don't have any SMD paste, or if you find the one you
have has dried out.

>
> I have a hot air tool and all the
> gear needed to do it properly,
> however when I want to do it quick
> and dirty I just use a butane torch.
> (only on prototypes mind you)

Which hot air tool do you have?
We plan to puchase SMD tools at work, and i am looking for likely candidates.

The only time i tried to tin a QFN part with 60/40 and iron i promptly
ripped out one of the pads of the IC. Suffice to say first thing i did
was order a syringe of SMD paste.



I also use a very large tip on the iron as "pinpoint hot plate" to
replace small 8 pin QFN with thermal pad. Just place it opposite the
IC (it is a thermal design with many VIAs so heats through well). I
have also replaced 32 pin QFN by heating from the top with a large
glob of solder on a large tip. Not good, takes long, but the ICs
survive. Almost anything is better than this method though.


>
> I then place the target PCB on a
> scrap of FR4 and preheat from
> below for a bit.  I then move the
> heat to the top side and very
> gently continue the heat.  When I
> see the chip move and allign itself
> I give it a bit more heat close up
> and then back off and let it cool
> slowly.

When i reflow PCBs i too put them on a scrap of PCB (actually a
special material that the PCB supplier puts under the boards for
drilling, he puts those scraps in the package when shipping and they
make a great heat-proof surface to solder on)

Then i heat with a temperature adjustable hot air gun, usually only from above.
As you can see  we really need to purchase some tools at work, but i'm
unsure what is best. There are hot air pencils, slightly larger hot
air tools but still smaller than a heat gun, then there are preheat
(and possibly reflow) hotplates, and reflow ovens, and infrared
heaters, and lotsa other stuff. I'm wondering what will be most
useful.

> The fine needle tips I have
> (on a Hakko) just don't get the heat
> down the business end fast enough.
>

That is true, i have few uses for the very sharp long tip and when i
use it i must increase the temp. setting to get anything molten. I
don't even attempt leadfree with that tip.

> I get much better results dragging
> the solder away with a tip that is
> over a mm than one that is 0.7mm.

Same here.

> Also touching new solder to the pool
> very regularly to keep flux in the
> game helps me out.

I found that SMD soldering paste has more/better flux. So often i will
apply some of that, and then drag-solder over it.
Stupidly i just bought 1.5kg of solder that doesn't have very good
flux, or possibly too little. I especially ordered the more expensive
solder with 5  flux cores (Edsyn), expecting to get something good,
that it will wet well, but it turns out the opposite is true. The
total percentage of flux is much lower than with the old solder. It
will take years to use it all up.....

ST

----- Original Message ----- 

From: "Andrew" <andrewm1973@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, August 18, 2007 11:09 AM
Subject: [Homebrew_PCBs] Drag soldering.


> However the QFNs that you can hardly
> see the pads on the side of there is
> not much choice but to reflow them.
> Also anything with an exposed pad
> you must reflow.


I do thermal pads by putting a hole in the centre of the pad hole and 
feeding solder in whilst melting it with the iron tip. The RF heating used 
by Metcal helps a lot with this sort of thing.

Leon

> ST wrote:
> Which hot air tool do you have?
> We plan to puchase SMD tools at
> work, and i am looking for likely 
> candidates.

Most of my soldering equipment is
Hako, however I bought a cheap
hot air gun that is a chinese rip-
off of the Hako.  It works fine
but is noisy and the handle has
melted a bit.  Next time I am
ordering more Hako parts I will
get a real one and one of their
little hot plates to preheat the
board with.


> The only time i tried to tin a
> QFN part with 60/40 and iron i 
> promptly ripped out one of the
> pads of the IC. Suffice to say
> first thing i did was order a
> syringe of SMD paste.

I have yet to rip a pad off but
I guess it is something to look
forward too.

> <SNIP about different option>
> I'm wondering what will be most
> useful.

Hot air tool is probably most
general purpose.  You can rework
and do small production runs.

You can't rework with an oven but
is going to be quicker for runs
of boards especially if you have
stencils.

Hotplate is helpful but not
esential when using the hot air
rework tool.

> <SNIP>
> Stupidly i just bought 1.5kg of
> solder that doesn't have very
> good flux, or possibly too
> little. I especially ordered the
> more expensive solder with 5
> flux cores (Edsyn), expecting
> to get something good, that it
> will wet well, but it turns out
> the opposite is true. The total
> percentage of flux is much lower
> than with the old solder. It
> will take years to use it all up.....

Throw it away.  The amount of money
wasted is probably not worth the
torn out hair :)

> > andrewm worte:
> > However the QFNs that you can hardly
> > see the pads on the side of there is
> > not much choice but to reflow them.
> > Also anything with an exposed pad
> > you must reflow.


> Leon wrote:
> I do thermal pads by putting a hole in
> the centre of the pad hole and feeding
> solder in whilst melting it with the
> iron tip. The RF heating used by
> Metcal helps a lot with this sort of
> thing.

Good idea feeding the solder through a
large hole.  Does the hole have to be
plated through or will it work on
home made boards ?

Would not have worked for that last
board I posted though :(.  This is
the back side of it

http://www.thehacktory.com/Simple-IR-RX-Prototype-V1p4-Bottom.jpg

Yes - the little surface mount IR
receiver module is directly behind
the QFN28-4.

----- Original Message ----- 

From: "Andrew" <andrewm1973@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, August 18, 2007 12:09 PM
Subject: [Homebrew_PCBs] Re: Drag soldering.


> 
>> Leon wrote:
>> I do thermal pads by putting a hole in
>> the centre of the pad hole and feeding
>> solder in whilst melting it with the
>> iron tip. The RF heating used by
>> Metcal helps a lot with this sort of
>> thing.
> 
> Good idea feeding the solder through a
> large hole.  Does the hole have to be
> plated through or will it work on
> home made boards ?

It's easier with PTH, but I think I have used it on a home-made PCB.

Leon

"Leon" <leon355@...> writes:
> How do you solder the QFNs?

A couple of weeks ago we had a gEDA meeting here, and I reflowed some
QFNs on my hotplate.  Two power supply boards, two worked!  These were
0.5mm too, with a thermal pad.

http://www.delorie.com/pcb/hotplate/

Example reflowed board:

http://www.delorie.com/house/furnace/pcb2/

Yeah I've done the same- 'cept that my 're-flow- oven is a way crappy
toaster oven that has the poorest temp control right now- I am working
towards correcting that but is on backburner indefinately while I
finish up other projects.,, I've also used my conventional oven a long
while ago- untill I started thinking about the consequences...

 Hey- I wanted to ask DJ,, is your r8c programmer a home built? i am
looking for such a design as I canot afford to buy one at the moment....?

 QFN,, these days I if I am doing a proto with these packages,, (ie,
just did a bunch of MMA7260Q 3 axix accell breakouts), ratherthan
firing up the ol' toaster, I do them by hand- what I try to do is plan
the package footprint (or layout) for that in advance by extending the
pads outwards a bit so as to have something to 'tack' to with the iron
rather than having the pads hidden underneath the package itself.
Typically for a 'flag', I will attach one of the gnd pads to it in the
footprint or layout and secure the flag via the gnd pad (not robust
but works), and also heat up the flag if possible by touching the iron
to the underside on the bottom layer(or opposite PCB layer, that is)-
plan ahead for this and tin the flag nicely or use solder paste-
whichever you use. Liquid flux is very handy to use for these
situations because it will get right under there without problem and
greatly aid in the 'speading' of whatever solder materials are
there....(cut it 1:1 with alcohol to thin it out, dump it into a tiny
syringe and off you go...)

m2c,, cheers, jd

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:

>
> 
> "Leon" <leon355@...> writes:
> > How do you solder the QFNs?
> 
> A couple of weeks ago we had a gEDA meeting here, and I reflowed some
> QFNs on my hotplate.  Two power supply boards, two worked!  These were
> 0.5mm too, with a thermal pad.
> 
> http://www.delorie.com/pcb/hotplate/
> 
> Example reflowed board:
> 
> http://www.delorie.com/house/furnace/pcb2/
>

"timbomcnuckle" <jaydag71@...> writes:
>  Hey- I wanted to ask DJ,, is your r8c programmer a home built? i am
> looking for such a design as I canot afford to buy one at the
> moment....?

Yup.  You need a serial port and two GPIO (mode and reset).  In
theory, you can do it with a standard rs-232 port with a suitable TTL
level shifter, if you don't mind doing the two GPIO with jumpers (it's
just to get the device reset into program mode, instead of into user
mode).  The protocol is pretty trivial, and well documented.

I had the same experience. We have some of the 5 core / multi-core
stuff at work and it's performance is poor. Either not enough flux or
the flux isn't as good, not sure which. I won't use it anymore at all.
I like the Kester 63/37 RA '44' solders. They're also available in
60/40 but I prefer 63/37. Good wetting, nice flow with clean bright
joints, and the tips of the iron stay in much better shape.

I also keep some Kester paste flux on hand as well. It's great for
tinning boards. I smear a thin layer over the board with my finger and
then drag a long tip sideways (so the side of the tip contacts the
board) over the board, I can tin a whole board in a few seconds. It's
getting harder to find but it's Kester Rosin Paste Flux SP-44. Handy
to have on hand when you just want a little dap someplace and not the
puddle from the liquid stuff. Just don't leave it out on the bench as
everyone thinks it's tip cleaner for some reason :-|

Phil

> I especially ordered the more expensive
> solder with 5  flux cores (Edsyn), expecting to get something good,
> that it will wet well, but it turns out the opposite is true. The
> total percentage of flux is much lower than with the old solder. It
> will take years to use it all up.....
> 
> ST
>

----- Original Message ----- 

From: "pgdion1" <pgdion1@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, August 21, 2007 4:03 PM
Subject: [Homebrew_PCBs] Re: Drag soldering.


>I had the same experience. We have some of the 5 core / multi-core
> stuff at work and it's performance is poor. Either not enough flux or
> the flux isn't as good, not sure which. I won't use it anymore at all.
> I like the Kester 63/37 RA '44' solders. They're also available in
> 60/40 but I prefer 63/37. Good wetting, nice flow with clean bright
> joints, and the tips of the iron stay in much better shape.
>
> I also keep some Kester paste flux on hand as well. It's great for
> tinning boards. I smear a thin layer over the board with my finger and
> then drag a long tip sideways (so the side of the tip contacts the
> board) over the board, I can tin a whole board in a few seconds. It's
> getting harder to find but it's Kester Rosin Paste Flux SP-44. Handy
> to have on hand when you just want a little dap someplace and not the
> puddle from the liquid stuff. Just don't leave it out on the bench as
> everyone thinks it's tip cleaner for some reason :-|

I must try that. I have used desolder braid containing plenty of solder with 
the soldering iron to tin pads (not the whole board) but it tends to lift 
them off. I'll try my Weller Pyropen with the paste instead of a soldering 
iron tip.

Leon

I've also got a page on liquid tin, which I now use for tinning
boards.  No flux mess to clean up afterwards.

http://www.delorie.com/pcb/liquidtin/

Thanks for the recommendation, i should've asked before buying.
I've used it now for a few days, and it's OK for most stuff. Doesn't
leave much visible flux residue so that's something good, i suppose.

Maybe if i leave the bad solder out on the bench it'll grow legs, worth a try.
(That'll teach them :-)  )

But i'm afraid i might not get to buy the Kester 63/37, they are
pestering us about leadfree....

ST

On 8/21/07, pgdion1 <pgdion1@...> wrote:
> I had the same experience. We have some of the 5 core / multi-core
> stuff at work and it's performance is poor. Either not enough flux or
> the flux isn't as good, not sure which. I won't use it anymore at all.
> I like the Kester 63/37 RA '44' solders. They're also available in
> 60/40 but I prefer 63/37. Good wetting, nice flow with clean bright
> joints, and the tips of the iron stay in much better shape.
>
> I also keep some Kester paste flux on hand as well. It's great for
> tinning boards. I smear a thin layer over the board with my finger and
> then drag a long tip sideways (so the side of the tip contacts the
> board) over the board, I can tin a whole board in a few seconds. It's
> getting harder to find but it's Kester Rosin Paste Flux SP-44. Handy
> to have on hand when you just want a little dap someplace and not the
> puddle from the liquid stuff. Just don't leave it out on the bench as
> everyone thinks it's tip cleaner for some reason :-|
>
> Phil

I would have thought the multi-core was better too, I was surprised by
the results I had. You have my sympathy on the Lead-Free. I don't know
about anyone else, but me and Lead-Free haven't gotten along to well
so far. Outside of plumbing (the no lead plumbing solder seems to
still sweat pipes just fine) I haven't liked the lead-free results. It
just doesn't seem to reflow like the tin-lead does. Takes a lot more
heat which crusties up the tip faster and also is hard on some of my
boards. Sure not like the Kester '44'.  Maybe I need to switch to
using a torch for the pcb's too ;-)
- phil
>
> Thanks for the recommendation, i should've asked before buying.
> I've used it now for a few days, and it's OK for most stuff. Doesn't
> leave much visible flux residue so that's something good, i suppose.
> 
> Maybe if i leave the bad solder out on the bench it'll grow legs,
worth a try.

> (That'll teach them :-)  )
> 
> But i'm afraid i might not get to buy the Kester 63/37, they are
> pestering us about leadfree....
> 
> ST
> 
> On 8/21/07, pgdion1 <pgdion1@...> wrote:
> > I had the same experience. We have some of the 5 core / multi-core
> > stuff at work and it's performance is poor. Either not enough flux or
> > the flux isn't as good, not sure which. I won't use it anymore at all.
> > I like the Kester 63/37 RA '44' solders. They're also available in
> > 60/40 but I prefer 63/37. Good wetting, nice flow with clean bright
> > joints, and the tips of the iron stay in much better shape.
> >
> > I also keep some Kester paste flux on hand as well. It's great for
> > tinning boards. I smear a thin layer over the board with my finger and
> > then drag a long tip sideways (so the side of the tip contacts the
> > board) over the board, I can tin a whole board in a few seconds. It's
> > getting harder to find but it's Kester Rosin Paste Flux SP-44. Handy
> > to have on hand when you just want a little dap someplace and not the
> > puddle from the liquid stuff. Just don't leave it out on the bench as
> > everyone thinks it's tip cleaner for some reason :-|
> >
> > Phil
>

Nice looking board. I've always wanted to try this stuff, maybe I
should give it a whirl. Jameco used to sell something like it in a
powder form but I don't see it in their catalog anymore. I'll look up
the MG stuff you used. Thanks for the tip.
- phil

--- In Homebrew_PCBs@yahoogroups.com, DJ Delorie <dj@...> wrote:

> I've also got a page on liquid tin, which I now use for tinning
> boards.  No flux mess to clean up afterwards.
> 
> http://www.delorie.com/pcb/liquidtin/
>

Tell the safety guy to get you some lead free that works like lead and 
you be glad to use it as soon at he personally demonstrates to you on it 
works as well on the prototypes you make.  Looking back over your posts 
you aren't doing production or even complete broads for the most part.

Everyone's panties are in a wad over the toys from China with lead paint 
and I have yet to see how much lead is in the paint.

When the press gets the bit in their teeth they can really wreck things. 
Look at the mad cow deal in the UK. Mad cow disease affected 2% or 3% of 
the cattle in the UK and less than 200 people. It has cost the world 
billions if not trillions of dollars and the problem is all but gone 
when the found that it was caused by feeding cattle to cattle and 
switched to vegetable protein and quit putting old cattle in food for a 
while. It takes a few years to dispersal but its a non problem now to 
all but the press and those that make a living off it. Yet when you look 
close enough all animals have a very very rare disease similar to it 
that pops up in 1 in a 1,000,000 animals or people and every time they 
find one it cost several million dollars.

Lead is more serious than Mad Cow disease. But for prototyping and 
rework it poses no treat to anyone but the person doing it if they don't 
follow basic safety rules.

Gordon

pgdion1 wrote:

>
> I would have thought the multi-core was better too, I was surprised by
> the results I had. You have my sympathy on the Lead-Free. I don't know
> about anyone else, but me and Lead-Free haven't gotten along to well
> so far. Outside of plumbing (the no lead plumbing solder seems to
> still sweat pipes just fine) I haven't liked the lead-free results. It
> just doesn't seem to reflow like the tin-lead does. Takes a lot more
> heat which crusties up the tip faster and also is hard on some of my
> boards. Sure not like the Kester '44'. Maybe I need to switch to
> using a torch for the pcb's too ;-)
> - phil
> >
> > Thanks for the recommendation, i should've asked before buying.
> > I've used it now for a few days, and it's OK for most stuff. Doesn't
> > leave much visible flux residue so that's something good, i suppose.
> >
> > Maybe if i leave the bad solder out on the bench it'll grow legs,
> worth a try.
> > (That'll teach them :-) )
> >
> > But i'm afraid i might not get to buy the Kester 63/37, they are
> > pestering us about leadfree....
> >
> > ST
> >
> > On 8/21/07, pgdion1 <pgdion1@...> wrote:
> > > I had the same experience. We have some of the 5 core / multi-core
> > > stuff at work and it's performance is poor. Either not enough flux or
> > > the flux isn't as good, not sure which. I won't use it anymore at all.
> > > I like the Kester 63/37 RA '44' solders. They're also available in
> > > 60/40 but I prefer 63/37. Good wetting, nice flow with clean bright
> > > joints, and the tips of the iron stay in much better shape.
> > >
> > > I also keep some Kester paste flux on hand as well. It's great for
> > > tinning boards. I smear a thin layer over the board with my finger and
> > > then drag a long tip sideways (so the side of the tip contacts the
> > > board) over the board, I can tin a whole board in a few seconds. It's
> > > getting harder to find but it's Kester Rosin Paste Flux SP-44. Handy
> > > to have on hand when you just want a little dap someplace and not the
> > > puddle from the liquid stuff. Just don't leave it out on the bench as
> > > everyone thinks it's tip cleaner for some reason :-|
> > >
> > > Phil
> >
>
>