13 Aug
2006
13 Aug
'06
7:16 a.m.
On Aug 12, 2006, at 4:50 PM, aliensrcooluk at yahoo.co.uk wrote:
These tools are mainly used for surface-mount assembly and/or rework.
The pneumatic solder paste pump is for dispensing solder paste in
metered amounts. Solder paste is tiny spheres of solder in a
semi-liquid flux carrier. It is typically sold in syringes that look
like the ones for medical use. For manual dispensing, you put on the
right sized tip (where the needle would go) for the size of pads you're
working with, and squeeze out some solder paste on each of the pads.
The trouble is, the paste is very thick, and (especially with
smaller-diameter tips) your hand will get tired and achy VERY quickly.
Pneumatic dispensers have a hose which clamps onto the "hand" end of
the syringe and pump bursts of compressed air into it to force the
solder out through the tip. The pressure and volume of the air is
tightly controlled by the dispenser unit to squeeze out the correct
quantity of solder. This is usually done under the control of a foot
switch.
A hot-air pencil is very simple. It looks like a standard soldering
iron, except instead of a solid metal tip that gets hot, it has a
hollow metal tip through which very hot air is blown. You basically
blow hot air at the joint you want to solder instead of transferring
the heat to it by touching it with the hot tip.
If you are interested in seeing what this stuff looks like, I can
take some pictures of my equipment and put them on a web server. Let
me know.
-Dave
--
Dave McGuire
Cape Coral, FL
I bought a
pneumatic solder paste pump for $75,
and two different
very high-end hot air pencils for $50 and $120, al
l
on eBay over the
past several years. The stuff is out there. $50
for an air pencil
which will likely run for decades is not a bad
investment in my opinion.
As a newish member and someone not
experienced in circuit board repairs/modification,
could someone please explain what they (the
pneumatic solder paste pump and the hot-air
pencil) do, please?