HI Lyn:
I picked up a PUK 3 Pro + just after christmas. Unfortunately, I
haven’t had as much time to play with it as I would have liked, but
what I’ve discovered thus far are the following:
(A) you want their microscope. I used their auxiliary shutter fitted
to a stereo scope I already had. The field of view through the
shutter is pretty limited. (the sides of the shutter clip the
outboard edges of the view through both eyepieces, so you’re working
in a little oval of clear vision in the middle.)(the shutter’s not
wide enough for my scope’s optics.) Get theirs.
(B) they say it’ll work with industrial argon. This may be true, but
it’s much happier working with grade 5 argon, especially if you
plan on doing titanium. The drawback is that industrial argon runs
$50/bottle, while grade 5 is $200+/bottle. Check with your local gas
house about the relative prices, and keep them in mind when
evaluating costs. (Of course, lasers pretty much require grade 5, so
that’s a wash, but be aware of it.)
© get their argon regulator. I already had an argon setup, so I
figured my existing argon regulator would work just fine. Errrr…not
so much. The PUK likes really low pressures, and standard regulators
get twitchy down around 2-3 PSI. I can make it work, but I suspect
the dedicated regulator would work better.
I bought it primarily for working on reactives, but I do a bit of
silver work as well. The things I’ve discovered about it are as
follows: It does titanium & niobium beautifully, with a few tweaks.
It actually does niobium better than the laser I used previously.
The Pro+ version has more power than the others, and you need every
bit of power you can scrounge up to get silver to weld. I’m still
dialing in my silver technique, but it’s the most difficult metal to
weld, either with lasers or arc. (lasers it reflects, and arcs it
conducts. Not a fun metal) Copper has some of the same issues with
conducting the arc rather than welding. I’ve done a little stainless
& brass with it, and those both worked pretty well, the stainless
more than the brass.
It uses small tungsten electrodes to target the arc, and it chews
them up quickly. It comes with a box of 10, double ended. You’ll blow
the end off an electrode in 10-15 shots. Fewer if you’ve got the
power cranked up for silver. The good news is that they’re reasonably
easy to resharpen, and you can reuse them until they get ground down
to the point where the handpiece won’t hold them. I think I’ve found
an industrial supplier of tig electrodes that has a similar size, so
I want to try those to see if they work. They’re cheaper. I keep a
pile of sharpened electrodes, chew through them all, and then
resharpen the whole batch in one go, while I have my jig set up. It
seems faster that way.
They say to keep the electrodes ground to a 15 degree point, and
always change the tip when it gets blown away. This is true if you
want very deep, or deadly accurate shots. If you’re just trying to
tack something into place for soldering, or rolling along a seam,
you can let the tip of the electrode blunt itself, and you’ll still
do fine for most things. I do a fair bit of long seam welding in
titanium, and the PUK is clearly designed to be a spot welder. It’ll
do long runs, but it’s happiest doing individually targeted spots.
The Pro + has bigger capacitors, so it’ll recharge faster than the
other versions, with makes seams much easier. I find that it
recharges about as fast as I can shift my hand, and retarget the
tip. I don’t spend time waiting around for it to fire. (about 3 shots
every 2 seconds or so). Not as fast as a laser, but then again, it’s
not $30,000 either.
One of my favorite laser tricks was to open the beam out wide, and
use that to ‘smooth’ the joints in a second pass. Not going to happen
with the PUK, especially on silver. It tends to blast silver into
pits and balls, but as I said, I’m still dialing in my silver
technique. I’ve seen pictures (from them) that indicate that it is
possible to get a nice tame weld puddle on silver, but I haven’t
managed it yet, in the few times I’ve tried silver. (But silver’s no
cakewalk with a laser either.)
Hope this helps,
Brian Meek.