Re: Source of poor solder joints?

[Mark - W5EZY]

I agree with all Tom has stated, but to add a bit
more(I didn't see mention of this), after cleaning the
tip well I will dab just a touch of solder to the
right before touching the joint to establish a
"bridge."  This helps the transfer of heat quickly to
the joint so that you're not applying heat too long to
that high quality but fragile circuit board.  Too much
heat for too long is a disaster to any pcb.  My $.02

73,
Mark Baugh
W5EZY
Grenada MS



 
____________________________________________________________________________________
Sponsored Link

Mortgage rates near historic lows:
$150,000 loan as low as $579/mo. Intro-*Terms
https://www2.nextag.com/
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Don Wilhelm-3]

Mark,

You are quite right in saying 'applying heat too long' is a problem.  It is
not high temperatures that cause problems but insufficiently high
temperatures applied for a longer time.  Components are designed to
withstand high soldering temperatures for a short time - they are designed
for wave soldering and other 'whole board' automated soldering techniques,
and component damage due to soldering heat is no longer a primary concern.

The way I check my soldering temperature is to see if I can make the solder
visibly flow in 2 to 3 seconds - if it does not flow in less than 3 seconds,
the iron is too cold, and if it flows in less than 2 seconds, the iron is
too hot.  My normal soldering temperature is 700 to 750 degrees for most
thru hole work and I use about 650 degrees for SMD work.  The actual
temperatur required will vary from board to board and it depends on the
copper area that is being heated.  Large areas of copper will conduct heat
away quickly and the iron temperature must be increased to compensate.

73,
Don W3FPR

> -----Original Message-----
>
> I agree with all Tom has stated, but to add a bit
> more(I didn't see mention of this), after cleaning the
> tip well I will dab just a touch of solder to the
> right before touching the joint to establish a
> "bridge."  This helps the transfer of heat quickly to
> the joint so that you're not applying heat too long to
> that high quality but fragile circuit board.  Too much
> heat for too long is a disaster to any pcb.  My $.02
>
> 73,
> Mark Baugh
> W5EZY

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Ron D'Eau Claire-2]

That's a critical point you made Mark: never solder with a "dry" tip. It
must be wet with a little solder. The wiping is to remove excess solder and
any burned rosin or other debris, not to dry the tip off completely.

That's one of the reasons it's so important to use the right size tip on the
iron. It's not just a matter of the tip reaching the joint without touching
other parts, but a big tip will take too much solder to "wet" it, and when
you heat the joint that solder may flood a small solder pad, but without the
rosin needed for a well-flowed joint. The right size tip allows a small drop
for good transfer, then more fresh solder is added with rosin to complete
the joint.

I use Don's technique for checking my iron temperature too: between 2 and 3
seconds for good solder flow over the joint. When I've worked on gear in the
field (ships, etc.) I'm often in a situation where I'm working on delicate
PCBs, even replacing SMDs at times, without a soldering station. I use my
butane powered "Port-A-Sol" pen iron. It's hot enough to burn a hole in a
PCB or de-bond traces almost instantly, but it has a fuel-flow control that
adjusts the temperature and has selectable tips. For fine work I install a
1.5mm tip and crank down the heat, setting it to produce good solder flow
between 2 and 3 seconds after applying the tip to the work. I've never
damaged a PCB or component with it following that rule.

Ron AC7AC


-----Original Message-----
I agree with all Tom has stated, but to add a bit
more(I didn't see mention of this), after cleaning the
tip well I will dab just a touch of solder to the
right before touching the joint to establish a
"bridge."  This helps the transfer of heat quickly to
the joint so that you're not applying heat too long to
that high quality but fragile circuit board.  Too much
heat for too long is a disaster to any pcb.  My $.02

73,
Mark Baugh
W5EZY
Grenada MS


_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Tom Hammond-3]

VERY GOOD POINT, Mark!

And yes, I do the very same. Just a 'touch' of added solder to 'wet'
the cleaned tip AND to provide that needed means of transferring heat
from one point to the next.

A 'dry' soldering iron tip WILL eventually transfer the heat, BUT a
'wetted' tip will accomplish the heat transfer MANY TIMES FASTER and
with less chance of 'frying' something in the process (component OR
PC board trace).

Good catch pal.

Thanks,

73,

Tom   N0SS


At 02:13 PM 11/22/2006, Mark Baugh wrote:

>I agree with all Tom has stated, but to add a bit
>more(I didn't see mention of this), after cleaning the
>tip well I will dab just a touch of solder to the
>right before touching the joint to establish a
>"bridge."  This helps the transfer of heat quickly to
>the joint so that you're not applying heat too long to
>that high quality but fragile circuit board.  Too much
>heat for too long is a disaster to any pcb.  My $.02
>
>73,
>Mark Baugh
>W5EZY
>Grenada MS
>
>
>
>
>____________________________________________________________________________________
>Sponsored Link
>
>Mortgage rates near historic lows:
>$150,000 loan as low as $579/mo. Intro-*Terms
>https://www2.nextag.com/
>_______________________________________________
>Elecraft mailing list
>Post to: [hidden email]
>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
>  http://mailman.qth.net/mailman/listinfo/elecraft
>
>Help: http://mailman.qth.net/subscribers.htm
>Elecraft web page: http://www.elecraft.com

_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com

[Ian Stirling, G4ICV, AB2GR]

On Wednesday 22 November 2006 18:13, Tom Hammond wrote:

> A 'dry' soldering iron tip WILL eventually transfer the heat, BUT a
> 'wetted' tip will accomplish the heat transfer MANY TIMES FASTER and
> with less chance of 'frying' something in the process (component OR
> PC board trace).

  I always clean my soldering tip on a DAMP sponge, not wet.
And I add a touch of solder to the tip, considering that it
is a molten tip, not transferring solder to the intended joint,
but transferring the heat efficiently.
  I built my K2 with a 15 Watt Antex soldering iron that
I bought in 1971 - no temperature control -
just experience, probably such as Don's timing tips.

  If anyone would like to look at my soldering,
http://www.opus131.com/ijs/infra.html
 Click on the pictures for detail - they are modest resolution
scans of prints from an Olympus OM4. These days a digital
camera could produce much more detail - maybe I'll update
the page one day.

Ian, G4ICV, AB2GR, K2 4962
--
_______________________________________________
Elecraft mailing list
Post to: [hidden email]
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
 http://mailman.qth.net/mailman/listinfo/elecraft   

Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com