TOOLS AND SUPPLIES
Portable Spot Welder
Merging metal the factory way, in your own garage
BY TERRY McGEAN
PHOTOGRAPH Y COURTESY OF HTP AMERICA
Spot welding generally involves a
pair of copper alloy electrodes,
which are placed on opposing sides
of two pieces of overlapped work material. When the electrical current is passed
through the electrodes, the intense heat
generated from the resistance at the work
material creates a small molten pool, and
the pressure being exerted by the electrodes promotes the molten metal from
each piece of work material to merge. In
just a few seconds, the process can join
the two pieces of metal with a relatively
small but durable bond.
This type of spot welding lends itself
to automobile production because it’s
simple, fast and effective. It also doesn’t
require the sort of skill that other forms
of welding mandate—in fact, very little
skill at all is needed to execute the weld
itself. Another benefit is that heat, inherent to all types of welding, can be localized to keep warpage of the work material
to a minimum.
A problem facing auto restorers is that
spot welds, though simple, are not necessarily easy to replicate in the typical shop,
largely because spot- welding equipment is
somewhat specialized, and the expense is
hard to justify for a low-production shop.
Even in collision shops that keep a spot-welder on hand, getting the tool into some
positions on an assembled vehicle can be
tricky, leading techs to reach for the more
commonly used MIG welder.
Factory-style spot welds are usually
replaced with MIG welds during restora-
tion, again mostly because it’s easy and
MIG welders have become common even
in home shops. After a spot weld is drilled
out, the hole in the remaining piece of
work material is simply “plug welded” with
a MIG to the new piece.
Experienced techs can
even make this look similar to a spot weld, while
others choose to grind
the weld down flush and
then strike the area with
a punch to simulate a factory spot weld.
But since spot welding is fairly simple,
and carries the additional benefit of eliminating flying sparks and slag, it should be
perfect for auto restoration. That’s what the
crew at HTP America was thinking when
it decided to add a portable spot welder to
its lineup of welding gear. The HTP Quick
Spot II is a relatively small unit, though it’s
capable of providing 6,000 amps of welding
power using a 220-volt feed.
The unit functions using the same principles as traditional spot welders, but
reduces the required skill level even further by utilizing a micro-processor control
panel, which allows users to simply enter
the work metal thickness for setup. From
there, you simply position the electrodes
over the work, squeeze the handles to
apply the pressure, and the unit creates a
uniform spot weld.
The Quick Spot can also be used in a
pulse mode, which we’re told is advantageous when attempting to burn through
primers. In continuous mode, the duration
of the weld can also be adjusted if desired.
According to the spec sheet, the unit is
good for joining two sheets of metal of up
to 14-gauge thickness.
In addition to being easy to use, the
Quick Spot also lends itself to the restoration market by being much less costly than
typical spot welding rigs; suggested retail
is $599. If you’re about to embark on this
sort of work, HTP also offers spot-weld
drilling tools to make the first stage of the
job easier.
Source
HTP America
800-USA-WELD
www.usaweld.com
54 HEMMINGS MOTOR NEWS • JULY 2009
