The alignment of pins is the most difficult part of surface mount
soldering. Don't bother with blue tack or expoxy. The most effective
means is by bumping up a pad in each corner of the device. By bumping, I
mean add a little bit of solder to the corner pads. Then lay the
component over the top of the pads and align some of the pins. As you go
tack in the outer pins to the bumped up pads. What this does, is
securely holds the device in place, while giving you enough freedom to
reflow your tacked pins and ever so slightly move the component into
place. Once you are absolutely happy with alignment you can then solder
all the pins, without having the residues from blue tac or the like.

> Hoof tips are made by Metcal (www.metcal.com) and perhaps others. From
> Metcal web site:
> "Metcal's SMTC-x147 "hoof" tip (so named because it looks like a tiny
> horse's hoof) is specially designed for multi-lead soldering, a fast and
> increasingly popular technique for attaching SMD 's including J-Leaded, fine
> pitch, and gull-wing packages. In multi-lead soldering, you apply solder
> directly to the tip of the soldering tool and then draw the tip with its
> reservoir of solder across a row of leads, one side at a time, until the
> device is firmly attached. The use of flux, Metcal's direct power delivery,
> and the nature of multi-lead soldering naturally "meters" the correct and
> uniform amount of solder for each connection without solder wicking ,
> lengthy dwell times, or other problems that can result in defective rework."

The Hoof tip also goes under the name of Miniflow / Continuous Flow tips
from Vanier. Don't be scared off by the cost of Surface Mount. I have
cheapest Hakko 926 with both a Miniflow and Hakko K-Bar (900M-T-K) tips
for my setup at home. Ideal for any QFP/TQFP components. The tips are
about $20 Australian and fit the Hakko irons.

The Miniflow/Hoof tips have already been described by Tom. The K-Bar is
a like a small knife with a point about 45deg. You can lay solder around
the perimeter of the device over the legs. Then using the K-bar, melt
the solder with one side of the knife over the pins, and gently pull
outwards. The most important thing about surface mount soldering - don't
worry if solder bridges the pins. Simply apply more flux and rework the
pins. With QFP etc, you don't solder each pin individually but rather
many at a time. With the right amount of solder, it will flow into the
joints giving a neat finish without any bridging.

Which tip you use is normally up to personal preference. I like to use
the K Bar for Gull Wing Components and the Miniflow for J Leaded
Components using Mini Flow Tip. However the K bar also has a pointy tip
which is ideal for tacking in your corner tips, thus you can use the one
tip for both jobs. This comes in ideal when you only have one iron, such
is normally the case at home.

> Sounds pretty good to me, anyone had experience with Metcal tips\irons?

I have a Metcal desoldering tool at work. Very nice unit. Too bad they
cost so much or I would buy one for home.

> Are there any cheaper manufacturers who make handpieces that accept Metcal
> STTC tips? Alternatively are there other hoof tips for cheaper irons? If so,
> are they as good? Metcal's smartheat technology sounds pretty neat. No
> temperature adjustment needed. And, the logic that you want to put as much
> heat in the chip in as short a time as possible sounds smart.
>
> Also, anyone know a cheap Australian supplier?

You could always try Mektronics for the Vanier and Hakko Tips. . . They
have agents in most states.

Regards,

Craig Peacock