Central Tendency of K2 PCB Solder Pad Widths?

[Jeff T. Casey]

Hi gang,

This document on the Elecraft web site,
http://bit.ly/solderingtips
says,
"[Soldering iron] tip width will normally be in the range of 1/32" (0.79mm) through 1/8" (3.2mm), depending upon the width of the pad to which you are soldering. The width of the tip selected should be about 75% to 90% of the width of the pad."

What would you estimate to be the median or modal (or just typical ;-) solder pad width on the K2's circuit boards?

Or, to be more direct, which of the following soldering tip widths would be best for use in building a K2: 0.80 mm, 1.19 mm, 1.60 mm, or 2.40 mm?

Or am I just splitting hairs?

Thanks very much, 73 & 72,
Jeff
NE2J (formerly WB5GWB)

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Ron D'Eau Claire]

I use a 1.6 mm chisel tip on my Hakko 936 soldering station for 99.9% of my
circuit board work including building and modifying the Elecraft K2, KX1, XV
transverters, and a variety of mini-modules, homebrewing lots of stuff and
repairing commercial gear.

The challenge is to transfer heat efficiently. Whoever wrote the Elecraft
doc on soldering was trying to give readers some way to judge whether a
given tip is "about right", but don't take 85%-95% of the trace width too
seriously.

Normally I place the flat side of the 1.6 mm chisel tip right against the
joint to be soldered and then add solder. If the pad is extremely tiny, I
just use the side of the chisel tip.

Solder should flow around the joint in about three seconds if the heat
transfer is correct. The danger to the pc board trace is in letting the iron
sit on the trace too long. Eventually the heat will debond the trace from
the board. That has very little to do with the temperature of the iron (as
long as it's hot enough to melt solder) and almost everything to do with the
length of time the iron is on the trace. Many folks make the mistake of
using too low of an iron temperature, requiring a long "dwell" time on the
trace, and are disappointed to see it debond even though the iron
temperature was at 700F or below. I normally solder at 750F or 800F.

I switch tips (or irons) when soldering to a large surface area of copper,
such as the ground plane covering one side of some boards or a coaxial
connector. A whole side of a pc board plated with copper or the big fittings
on coax connectors will immediately absorb and dissipate the heat. A large
tip helps transfer heat quickly, but you should still have an iron capable
of delivering the calories of heat needed. For example, my favorite coaxial
cable connector soldering iron, especially for soldering the braid to a
SO-239 connector, is a Weller 275 watt D-550 soldering gun I've had since
about 1955.

(All I have to do is wave that big gun near most circuit boards and I'm sure
I can see them cringe!)

Ron AC7AC

 
-----Original Message-----
Hi gang,

This document on the Elecraft web site,
http://bit.ly/solderingtips
says,
"[Soldering iron] tip width will normally be in the range of 1/32" (0.79mm)
through 1/8" (3.2mm), depending upon the width of the pad to which you are
soldering. The width of the tip selected should be about 75% to 90% of the
width of the pad."

What would you estimate to be the median or modal (or just typical ;-)
solder pad width on the K2's circuit boards?

Or, to be more direct, which of the following soldering tip widths would be
best for use in building a K2: 0.80 mm, 1.19 mm, 1.60 mm, or 2.40 mm?

Or am I just splitting hairs?

Thanks very much, 73 & 72,
Jeff
NE2J (formerly WB5GWB)

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Don Wilhelm-4]

Jeff,

You may be splitting hairs, but I prefer a 1.60 mm ( 1/16 inch) chisel
tip for most of my soldering.
The flat on the tip allows sufficient area to conduct heat onto most
solder pads, and work well for me.

More important than the size of the tip is to heat both the solder pad
and the component lead so you can see the solder flow out to an almost
invisible edge on both the pad and the lead.  If that happens in less
than 2 seconds, the iron is too hot, but if it takes longer than 3
seconds, the iron temperature is too low.  The temperature required will
vary depending on the surface area of the solder pad and the 'weight' of
the component lead - the larger areas will conduct heat away from the
point to be soldered more quickly and require a tip with more mass or a
higher temperature.

Experiment a bit until you are comfortable with the task.

73,
Don W3FPR

Jeff T. Casey wrote:

> Hi gang,
>
> This document on the Elecraft web site,
> http://bit.ly/solderingtips
> says,
> "[Soldering iron] tip width will normally be in the range of 1/32" (0.79mm) through 1/8" (3.2mm), depending upon the width of the pad to which you are soldering. The width of the tip selected should be about 75% to 90% of the width of the pad."
>
> What would you estimate to be the median or modal (or just typical ;-) solder pad width on the K2's circuit boards?
>
> Or, to be more direct, which of the following soldering tip widths would be best for use in building a K2: 0.80 mm, 1.19 mm, 1.60 mm, or 2.40 mm?
>
> Or am I just splitting hairs?
>
> Thanks very much, 73 & 72,
> Jeff
> NE2J (formerly WB5GWB)
>  
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

[Tom Hammond-2]

Hi Jeff:

I don't believe it has to be quite that 'analytical' an
approach.  The intent of my comments in the article were to try to
urge builders to use a soldering iron tip width which would not
easily overlap the pad width, thus promoting the potential for
dragging excess solder between pads or pads and lands.

I've built numerous K2's and other Elecraft rigs and, for the most
part, I think I've just about always used a 1.6 mm width tip.  I
believe I did go to a somewhat more narrow tip when I built the KX1,
because it was more densely populated, and thus more prone to
offering chances for shorts between pads/lands.

The idea is to just use a tip that's large enough to carry as much
'heat' to the joint as possible, while not being so wide that it
easily allows you to overlap the pad with the width of the tip.

Hope this helps.

73,

Tom Hammond  N0SS

At 21:09 10/28/2009, Jeff T. Casey wrote:

>Hi gang,
>
>This document on the Elecraft web site,
>http://bit.ly/solderingtips
>says,
>"[Soldering iron] tip width will normally be in the range of 1/32"
>(0.79mm) through 1/8" (3.2mm), depending upon the width of the pad
>to which you are soldering. The width of the tip selected should be
>about 75% to 90% of the width of the pad."
>
>What would you estimate to be the median or modal (or just typical
>;-) solder pad width on the K2's circuit boards?
>
>Or, to be more direct, which of the following soldering tip widths
>would be best for use in building a K2: 0.80 mm, 1.19 mm, 1.60 mm, or 2.40 mm?
>
>Or am I just splitting hairs?
>
>Thanks very much, 73 & 72,
>Jeff
>NE2J (formerly WB5GWB)
>
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html