[Elecraft] soldering suggestions?

[Craig Rairdin]

I think I used a 1.6 mm tip when building my kits. Your .05" falls between
my 1.2mm and 1.6mm tips so I'm not sure which they might call .05".

You might try turning up the heat a bit, say to 750F. 

It shouldn't take 30 seconds to get solder to flow. My normal technique is
to wipe the tip on the sponge to clean it, then apply a little solder to the
tip. The solder on the tip helps heat to flow to the pad and the part faster
than a dry tip. Touch the tip to the pad and the part so that the edge of
the chisel tip is in contact with the pad (the more surface area is in
contact with the pad, the better and faster the heat transfer. The tip
should also contact the part. Apply a little pressure so you get good
contact with the board and the lead. Again, good contact equals good heat
transfer. 

I touch the solder to either the opposite side of the lead from the tip, or
to the pad. If I don't immediately get solder flow, I touch the solder to
the tip to wet it and improve the heat transfer, then I can almost always
get solder to flow by touching either the pad or the part.

I've never noticed the flying-solder problem that you've seen. I've never
worn gloves and I haven't been burned even after building all four of the
Elecraft radios and several of the mini-kits. (I guess I shouldn't count the
K3 when talking about not getting burned.) :-)

So I think the secret is to use a little more heat, prime the tip with
solder, make sure you're laying the edge of the tip flat against the board,
use a little pressure, and make sure you have contact with the lead. Touch
the tip if necessary to get the solder flowing.

When it works right you should clearly see solder flowing on the lead and on
the pad, not just one or the other. 

Hope this helps. There are others here who are professionals who might give
better advice. I just know that what I'm doing is working.

Craig
NZ0R
K3/100 #25
K2/100 #4941
K1 #1966
KX1 #1499

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of rellis
Sent: Tuesday, November 20, 2007 3:07 AM
To: Elecraft at mailman.qth.net
Subject: [Elecraft] soldering suggestions?



Hi,

Having purchased a K1 kit, but never having soldered before, I've
been working up to it by working on some other kits, such as an
electronic die, a signal generator, and an active null modem. I'm
using a hakko 936 and I have a .05" chisel tip. The solder that
I'm using is kester SN60PB40 #66/44 .025. (It is my intention to
use this solder and the .05" tip when working on the K1.)

There are some peculiarities with soldering that I'm uncertain about.

First is the time required to hold the soldering iron tip to the
component and pc board. When working on the active null modem (from
fox delta), the pc board pad is minute (compared to the velleman
kits) and was appropriately size for the .05" tip. (They are
comparable to the pads on the K1 pc board.) However, only
rarely would the solder flow in the 3 seconds that is suggested
in the K1 manual to avoid damage to components. (I'm applying the
recommendations in the K1 manual to these other kits.) The only
occasions that the solder flowed within 3 seconds was when I'd just
finished soldering a nearby location, for example when working on
a 16 pin socket. The solder tip was clean and silvery; the temperature
was set to 700 degrees (though I did not verify that with a separate
soldering tip temperature guage). Any thoughts on what I might be  
doing wrong?

(The velleman kits that I assembled clearly needed a bigger tip than
I was using... 30 seconds was needed to solder some connections. I was
considering them to be mostly practise, as they were my first attempts
at soldering. Surprisingly, the electronic die did work. The signal
generator doesn't smoke, but there are no blinking lights to tell me
whether it is working correctly. )

I also sometimes noticed that, when soldering, a tiny piece of solder
would sometimes fly off the tip of the solder wire and would impact
the soldering iron about halfway up the metal shaft (two inches above
the solder tip). Is this indicative of a static problem? This occurred
two or three times. This made me want to wear gloves in addition to the
eye protectors that I had on.

thanks,
  robert


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