[Elecraft] Solder in Elecraft kits

[Don Wilhelm]

Tom,

There is no one universally 'good' solder.  Each builder has what is 
familiar to him and has worked well in the past.  I offer my own best 
explanations below:

I do know of one expert builder who uses .031 diameter solder for 
everything, including SMD construction - but he is an exception, I 
certainly could not properly control the solder amount on SMD if I used 
that diameter.  I personally choose .015 for thru-hole work and .010 
inch for SMD because I can control the feed rate, so that is what I 
recommend only because I have found it easy to work with.

Also I like the 63/37 alloy better than the 60/40 alloy.  It has no 
plastic state and has a much better chance of eliminating 'cold solder' 
connections that can result from movement of the connection while the 
solder is cooling.

I do not clean my soldered boards, but I like them to not have a heavy 
flux buildup - flux usually does not hurt, but it just looks messy IMHO. 
  So I use a mildly activated rosin core solder.  A more active rosin 
core is not needed when using fresh components that have not yet 
developed a significant amount of oxidation.

So if you like my reasons, you would choose something similar to Kester 
285 flux in a 63/37 alloy and a diameter of either .015 or .020 for 
construction of Elecraft kits - I actually prefer MultiCore solder 
because it wets easier than Kester, but is not as readily available.  If 
you have good experience with something else, it is not wrong as long as 
it does not have a flux that will void the warranty.

That being said, I can add one more thing - I simply hate doing rework 
on a kit that has been soldered with one of the lead-free solders. 
There is really nothing 'wrong' with it, but it certainly makes rework 
very difficult because it does not conduct heat very well and requires 
higher temperatures than the lead based solders.

If you have good experience with one solder and know its characteristics 
and can produce good results, there is no reason to change - but if you 
are new to soldering and have to ask which is 'best', I can only give 
you what works best for me - others may have great success with 
something different because their technique is different - you must 
develop your own techniques and in the process you will discover what 
works best for you.  If you do not know what a good solder connection 
looks like, I encourage you to read the soldering tutorial on the 
Elecraft website, it has several good illustrations.

73,
Don W3FPR

Tom McCulloch wrote:
> I haven't been following this thread, but the poster seems to make a 
> valid point.
> 
> I built K2 #1103 several years ago and the thinking at that time was to 
> use an alloy of silver solder.  So that's what I did.  Once my kit was 
> built I more or less ignored the posts regarding solder, but about a 
> year or so ago (I could be wrong here) I thought I read that using 
> silver solder was a bad idea.
>