Re: SMD soldering (off topic)

If you are going to hand solder this method seems to work well:

I wouldn't superglue them down, it's not necessary and will make it more
difficult to remove. You can remove surface mounted devices easily with a
heat gun set to about 300 deg C, but remove the heat as soon as the solder
melts. The idea is to melt the solder around the pins as quickly as possible
before too much heat goes into the component. Pre-heating the board from
below can sometimes help. A tip is to use very thin wire and feed this under
the component first, then you can make a kind of cradle so that you can just
lift the component off cleanly when the solder melts. Don't pull hard on a
hot component or you'll pull the pads off with it, pull very gently - once
the solder flows it'll come off easily.

To solder on, first clean up the pads with flux and a solder wick. Be
careful with the pads, once they are hot they can come off. Next apply a
little solder to one pad only. Solder the component down only on that pad,
and orientate the device over all the other pads. Then solder one opposite
pad down. You'll need a very fine tip iron to do this. Now you've got a
component correctly orientated with two pads soldered. Then you can solder
all around the device.

The key to soldering I think is to apply heat with the very fine iron tip to
the point where the pad and pin meet (i.e. you apply heat to both the pad
and the pin together), and when hot apply the solder at that point. As soon
as the solder starts to flow remove the solder, but keep the heat on just a
little longer until it has flowed properly. Keep a thin solder braid handy
to remove any solder that shorts pins. Apply some flux all around the
component before you start. Use thin fluxless solder, as sometimes the type
that has flux inside has flux that is incompatible with the external flux.
Silver loaded solder seems to be best for this IMO. If you use 'no clean'
type flux, then also choose a compatible no clean type solder, then the
board is then easier to clean as there is very little residue.

Some advanced techniques include running a soldering iron along the pins
applying solder as you go, but this can be a nightmare if it all goes wrong.
Also the use of a hot air pencil can produce excellent results.

Happy soldering!

Mark.

Mark Purcell, MAP Electronics Ltd.
web: http://www.mapelectronics.co.uk/
email: map-hdgEqy5R1AG+FmPSFd0fl9Bc4/[email protected]

----- Original Message -----
From: "Tom Blough" <[email protected]>
To: <tini-6tN4nzCoH/[email protected]>
Sent: Monday, January 19, 2004 3:26 PM
Subject: [TINI]SMD soldering (off topic)


> I know some of you out there are hardware guys and were wondering if
anyone
> had any pointers on hand soldering surface mount devices.  I'm going to
make
> a few boards to play with some of the 1-wire devices and have never done
> SMDs before.
>
> I'm thinking of supergluing (any problems with the superglue electrical
> wise?) the chip down, fluxing the leads, and then heating and applying
> solder to the pads (0.015 tip and solder).
>
> Will this work?  Any other methods for hand soldering?
>
> TIA,
>
> Tom Blough
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