I've soldered a LOT of components to circuit boards and I've always cut
the leads prior to soldering.
I insert the component and flip the board over to see which direction
the runs go from the lead. I bend the lead in the direction of the run,
which serves the purpose of holding the component in place while I
insert more components and do the same to them. Once I have several
components installed I trim all the leads and solder them.
For me, this serves more than one purpose.
1. It holds the part securely in place prior to soldering.
2. The wire is pressed against the inside edge of the pad, which
facilitates solder flow at the connection.
3. I can get the tip of the soldering iron closer to the joint between
the lead and the pad by putting it opposite the direction the lead was bent.
4. It results in a MUCH lower profile on the back side of the board ...
which means less chance of something shorting in tight spaces.
5. I can more easily determine a bad solder joint. If the solder
doesn't wick along the run under the wire I know it didn't take. It's
easy to end up with rosin between the joint without noticing it when the
wire goes straight up.
The only downside I've ever had is like the other guy said ... it's a
total PITA to replace a component that has been soldered like that.
Dave AB7E
On 3/25/2018 9:18 AM, Don Wilhelm wrote:
I agree, the stated NASA "method" does amaze me.
First, the K2 is not likely to go a space journey.
Components with pre-cut leads may require 3 hands. One to hold the
component, one to hold the soldering iron and another to hold the solder.
I would assume that NASA directive was for wave-soldering boards and
does not apply to hand soldering.
I personally have a guideline which says "do not ever trim an
unsoldered lead" - watch as you trim and go back and solder it.
Of course, I am one who inserts multiple components before soldering.
I have never seen a failed solder connection in my work nor had any
reports of solder joint failure from those I have built the K2, K1,
KX1 or XVseries transverters.
73,
Don W3FPR
On 3/25/2018 11:33 AM, James F. Boehner MD via Elecraft wrote:
Jerome,
Now this is interesting. This is totally opposite of the way most of us
were taught to solder. Among the kits I used to put together were
Heathkit
and Ramsey, both of whom recommended securing the parts in place by
spreading the leads, soldering, and then cutting the wires close to the
solder blob, checking for shorts. I assume that goes for Elecraft
also, but
I have not built any of their radios as kits, so not sure.
So how did NASA handle the potential difficulties? Did they have precut
parts? Did the tech have to place the part in the board and cut the
leads
first? If the part was loose, how was it held close to the board,
owing to
the fact that holding the solder and the iron took two hands? What if
the
lead length was overestimated and potentially could cause a short?
Could
the wire be cut and the joint reheated, or did the part have to be
removed,
recut and reinserted?
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