Tac or pulse arc welders


Can anyone please explain the performance differences between the
cheaper tac welders and the more expensive pulse arc welders. I
mostly just want one for tacking pieces of metal together before
soldering. Is the weld with a pulse arc welder significantly deeper
and stronger than that of the cheaper intelitac or ABI tac II type
welders. What are the main benefits of the more expensive welders.

Thanks for your help
Phil Walker

Tack welders make a very weak surface bond between the pieces. They
work best for like metals (14k yellow to 14k yellow etc) don’t work
at all or very poorly to silver.I was not pleased with how the one I
had preformed. There is one type of tack welder that makes good
permanent bonds by using specialized findings and fixtures to
position the parts for welding. The Sparkie is an example of this
kind of tool but it will not work for free hand tacking of parts
together. You must use findings that have the “nib” that allows for
the proper bond and the parts are driven together with air or spring
pressure in a machine fixture that tends to limit its usefulness on
one of a kind work because you really need the fixture to hold the
work to get the best bonds.

Pulse arc welders are a miniature TIG spot welder with a much
greater depth of penetration and resulting strength of the weld but
can also make large holes in work if you don’t have your welding
skills developed. They have a very definite learning curve. I had a
ABI Tack 2 and found it to be basiclly useless to me and it had
reliability and service issues that made me get rid of it as soon as
I could. I love my PUK II (I have 2 of them in my shop) and would not
buy an ABI unit again. I have tried the RDO micro welder which is a
more powerful unit than the PUK or ABI pulse arc welders. It is great
but about twice the cost of the PUK II. If it was a little less in
price I would probably have bought one.


James Binnion
James Binnion Metal Arts



Thanks for posting about the PUK II and the RDO micro welder. I am
actually on the verge of purchasing the PUK II with the stereo
microscope, but thought I should get more info about the RDO. When
you say it’s more powerful, what does that mean exactly? Does it
work better on thicker metal gauges, thinner metal gauges, is it
more accurate and easier to use, does it produce cleaner/smaller
welds? And could you also provide some insight into how these pulse
arc welders compare to laser welders (besides being much less in
price). In other words, what can laser welders do that can’t be done
with the PUK II or RDO micro welder?

Thanks for sharing your experience with the rest of us on the forum.

Bonnie Cooper


In other words, what can laser welders do that can't be done with
the PUK II or RDO micro welder? 

I’ve never used either of those two welders but I have worked with a
laser. From the literature I’ve seen, it appears to me that the
limitation with the electric welders is that you have an electrode of
some sort. With a laser you have a beam that has no ‘physical
presence’. I was able to shoot deep inside very small or narrow
recesses, like welding the inside of a tube while the hinge was
assembled. The electrode would, I assume, need to be hand held. Both
hands are free to align parts with a laser.

One can also ‘push’ the metal around with a laser. This is useful
when you don’t have a perfectly matched joint, you can bridge a small
gap., then go back in and fill with laser wire.

I was not thrilled with the work involved to size a ring with a
laser. You basically must file the ends of the joint to a deep bevel
and fill in with wire to the surface…tedious. I’d be interested in
how the electrics do in that regard.

I’m saving my pennies for a laser. Rio Grande has a neat looking
small unit for around 15K, which I will test drive at the New York
Show after the busy season. 'Tis a hard choice for me though…a
laser…or a Harley-Davidson. Boys and their toys.


The RDO has more power this means it will make a larger deeper weld
puddle. What this means as far as your use of the machine well it
depends on what you are working on. It doesn’t seem to be much
different otherwise if you are looking at the PUK with the
microscope then they are pretty similar except for the power
difference. In many cases you may not need the extra power. However
if you work silver or copper you will find the extra power very
useful. If you work larger work then the extra power will be useful.
It really all depends on what you work with.

It is hard for me to make real comparisons with a laser as I don’t
own one and have very little time using one. I probably can do 80 %
of what a laser is used for in the typical shop with my PUK II but
slower and with a steeper learning curve. But it cost 1/10 of what a
laser cost so I am willing to learn how to work with it as I do not
believe I could make a laser pay for itself in my shop. In many
stores that do lots of repair a laser is able to pay for itself
without too much trouble.

James Binnion
James Binnion Metal Arts


Hi Bonnie,

I hope you don’t mind me weighing in. I am a former owner of an ABI
machine (and completely agree with Jim, I’d never buy one again), a
former owner of a PUK II, and a current owner of an RDO. After having
owned all of these machines, I’d unequivocally give “the nod” to the

The RDO does have more power than the PUK II. This makes it easier
to weld the more difficult materials out there, and is especially
handy with welding silver.

I’ve found the RDO easier to use than the others (easier than the
ABI, because the RDO actually works, and easier to use than the PUK
in the short term, but the PUK does get easier to use the more you
use it). This even takes into account the fact that the instruction
book is pretty terrible for the RDO. You can see what you are doing
with the RDO. The RDO uses an optical shutter arrangement, while the
PUK uses a welding filter. With the PUK, you are always looking
through the darkened (has a green tint) filter while you are getting
ready to weld - I found this a tremendous pain in the butt when
trying to use the 'scope with it. The RDO has a clean, well lit,
clear view. Initial units (mine and one that Jim used) had shutters
that did not work 100% - a dangerous situation. This has been
corrected, and they even sent a repair tech to my studio to install
a new board - great service! The RDO allows for user input, as well.
(argon pre-flow, power, weld duration) Another huge benefit of the
RDO (and lasers, and the PUK with the optional torch holder), is the
foot pedal operation. This allows you to use both hands for
steadying of the workpiece.

The RDO also produces multiple welds quickly, cleanly and
efficiently - easily allowing the stitching of multiple welds
together. Power is constant, and does not “drop off”. An air nozzle
makes cooling your work frequently very easy, saving you the cooked
fingertip feeling when doing multiple welds. In order to get this to
work, you need a compressor - it’s not necessary to the function of
the machine, but is a nice comfort feature! You simply connect the
compressor to the machine. The RDO is in it’s own “box” - this allows
the argon to puddle, so you can get nice clean welds, and even work
on titanium successfully (eyeglass frame repairs are easy). But,
this does limit you to what size item you can stuff in the box and
weld. Angle of “attack” can be difficult with the fixed torch, but
they do have a ceramic insulator that you can slide over the
tungsten electrode, allowing you to be very creative when
positioning work to weld.

I have a friend with a laser welder (a Rofin) - he used to get all
of my welding jobs. He doesn’t anymore. I have not found a job yet
that the RDO can’t handle (I am sure they are out there). It has
definitely helped me with some difficult fabrication problems. Every
time I use it, all I can do is think of more things to weld with it!
I have recently heard about “laser polishing”. I am not sure what
this is, but the RDO does not seem to polish anything! Also, lasers
do require maintenance - so far, all the tig systems I’ve used only
require sharpening of electrodes (save the optical shutter board
replacement - hardly “routine” maintenance).

And not to take away from the PUK II - it is a great machine, but
does not work as well as the RDO in many of my situations…but, it
is less expensive, and having the “pen” style torch does allow a lot
of freedom in how you approach larger objects. It also is well made,
nice looking, and takes up less studio real estate than the RDO. I
know Jim loves his PUK II’s.

But if you have the ability to, I’d buy the RDO in a second.
Gesswein is the distributor - Elaine Corwin can answer any technical
questions you may have. At RDO, the “main man” is Bob Okner. I even
think they are having a sale now - I remember a big poster at the
Providence MJSA show.

Good Luck,

Chris Ploof Studio

508.886.6200 (EST)