Easy-peasy SMD construction
On Thu, 19 Jun 2014, Jim Mueller wrote:
On Thu, 19 Jun 2014 16:24:46 +0100, gareth wrote:
Increasingly, components are more available in SMD form than in leaded
varieties.
Now, I have not tried the following, it is a suggestion as I'm bogged
down in other projects ...
With a single-sided PCB, used as the earth plane, glue the SMD
components down on the fibreglass side, allowing at least 1/4" either
side of each component. This is to ensure that there is room for your
soldering iron and allows for decreasing eyesight and wobbly fingers.
When the glue is dried hard, then wire together using that pink stuff
that does not need the enamel to be stripped before soldering.
And I mean HARD!
But be cautious over some glues that release when heated,
such as cyanoacrylate super glues and the Brit Araldite.
Another way is to use perfboard with pads on one side every 0.1" (and no
ground plane in between!). The other side can be bare, ground plane,
more pads, or whatever is needed. 0805 and 1206 size components can be
easily soldered between the pads, perhaps even 0603. Several components
can be soldered to one pad, each going in its own direction; this is for
where several components have a common connection.
For ICs with 0.05" lead spacing, bend every other lead up and solder the
remaining leads to pads. The bent-up leads are connected in the air.
Sometimes, the circuit calls for adjacent leads to be connected together;
if this is the case, it may be possible to alter the bending sequence to
allow them to be soldered to the same pad.
ICs with lead spacing closer than 0.05" are a pain to hand solder even on
a correctly laid out PC board. And, of course, BGAs can't be hand
soldered at all.
An advantage over the OP is that you don't have to wait for glue to dry.
I have personally used these techniques both in building home projects
and breadboards for work. Sometimes using these methods with SMD parts
is easier than using leaded parts.
Don't use cyanoacrylate super glues on anything that will be heated; they
give off nasty fumes.
I seem to recall from early articles about surface mount the suggestion of
using a dab of flux to hold the component in place. It was only to hold
it until you actually had something soldered.
That said, I really think a good magnifiying glass or microscope makes
sense. I was trying to figure out something, and got out the jeweller's
loupe, and it's amazing how much bigger everything is. That's not going
to work for soldering, but getting good magnification that will stand on
its own is bound to help a lot. And good lighting. Looking at that board
with the loupe almost makes the idea of soldering surface mount within my
capability.
Michael
|