Back when I used to work in ships ('70s) I used to see the insulation guys
laying out large numbers of stud locations, then the welders would move in
with their stud guns and weld studs everywhere, then the insulation guys
would use the studs to hang insulation on the steel bulkheads and overheads.

Now I want to make a clamshell forge, and I figure I'll need a few dozen
studs welded into the "shells" and wired together with heavy wire to keep
the refractory in place. I don't own a stud gun nor, with the exception of
my shipyard experience, have I ever seen one. I remember them being sort of
like a spot welder except they were designed so you put a stud into the gun,
pressed the stud where it needed to go, and pulled a trigger. A big bunch
of sparks flew out and bobs'yer'uncle.

Anyone know anything about stud welding?

Grant Erwin
Kirkland, Washington

In article ,
Grant Erwin wrote:

Now I want to make a clamshell forge, and I figure I'll need a few dozen
studs welded into the "shells" and wired together with heavy wire to keep
the refractory in place. I don't own a stud gun nor, with the exception of
my shipyard experience, have I ever seen one.

Anyone know anything about stud welding?

If you don't know somebody with one, another approach seems to be
merited. I used one in a job I had for a few months 20 years or so back.
The studs on the one I used had a bit of a nub sticking out, which was
the part that got melted to stick it to the base metal. Massive
capacitor discharge. Your discription of use is correct (it did have to
be dialed in to the stud and base metal combination for a good weld).

You might simply weld (via a means you own, such as OA torch or MIG)
some anchor points for your wire to the shells, or drill through and use
threaded rod with nuts, or drill through and weld small diameter rods in
in place, or drill though and wind your wire through the holes, with or
without welding the holes back up, as you see fit. No special advantage
to a stud gun if you don't have one and it will take longer to find one
than it would to do the job some other way. I'm guessing you're making
one forge, not a production line where there might be more benefit to
speedy stud-shooting.

YMMV, etc.

--
Cats, Coffee, Chocolate...vices to live by

Grant,
there are 2 type of stud welders come to mind,
1 is for duct work made by duro-dyne the spot a
pin and the insulation is then laid over and washers
applied, then the pins are bent over. Those pins
I have seen are about the same size a regular
1/8" pop rivets. The other type is an autobody
repair technique that pins are spotted on the
damaged metal and the area is pulled back into
shape. Eastwood restoration tools had them?
Both were attached by a similar looking gun.
Lots of small sheet metal and body shops going
under may find one cheap!

Hope this helps!
tt

I remember them being sort of
like a spot welder except they were designed so you put a stud into the
gun,
pressed the stud where it needed to go, and pulled a trigger. A big bunch
of sparks flew out and bobs'yer'uncle.

Anyone know anything about stud welding?

Don't know about the application you describe, but you might check with your
friendly local body shop. They use a gun to apply a wire stud to body
panels, then pull on the wire studs to straighten
sheet metal. Same principal as a slide hammer dent puller, without drilling
a hole. IIRC, the studs
are 1/16" or so, a couple of inches long.

Bill

Grant Erwin wrote:

Back when I used to work in ships ('70s) I used to see the insulation guys
laying out large numbers of stud locations, then the welders would move in
with their stud guns and weld studs everywhere, then the insulation guys
would use the studs to hang insulation on the steel bulkheads and overheads.

Now I want to make a clamshell forge, and I figure I'll need a few dozen
studs welded into the "shells" and wired together with heavy wire to keep
the refractory in place. I don't own a stud gun nor, with the exception of
my shipyard experience, have I ever seen one. I remember them being sort of
like a spot welder except they were designed so you put a stud into the gun,
pressed the stud where it needed to go, and pulled a trigger. A big bunch
of sparks flew out and bobs'yer'uncle.

Anyone know anything about stud welding?

Grant Erwin
Kirkland, Washington

I see them in the odd autobody shop. Used as anchors for pulling dents
straight studs and rippled wire for a claw end puller. A few enquiries
around your area may find someone that can do it for you.

Cheers
Trevor Jones

Anyone know anything about stud welding?

The stud welding I've seen was on construction sites. The studs were called
"Nelson" studs, about 5/8"dia, varying lengths, with a head like a nail, but
much thicker. They were welded to structural steel and later had concrete
poured around them. The welder was just as you described, required a large
power service. If only a small quantity of studs were needed, the ironworkers
would sometimes weld them with a stick welder to avoid the hassle of setting up
the stud gun.
Gary Brady
Austin, TX

On Tue, 20 Apr 2004 19:33:51 -0700, Grant Erwin
vaguely proposed a theory
.......and in reply I say!:
remove ns from my header address to reply via email

Well you take....no...G
************************************************** **
I went on a guided tour not long ago.The guide got
us lost. He was a non-compass mentor.........sorry
.........no I'm not.

In article , Grant Erwin
wrote:

Back when I used to work in ships ('70s) I used to see the insulation guys
laying out large numbers of stud locations, then the welders would move in
with their stud guns and weld studs everywhere, then the insulation guys
would use the studs to hang insulation on the steel bulkheads and overheads.

Now I want to make a clamshell forge, and I figure I'll need a few dozen
studs welded into the "shells" and wired together with heavy wire to keep
the refractory in place. I don't own a stud gun nor, with the exception of
my shipyard experience, have I ever seen one. I remember them being sort of
like a spot welder except they were designed so you put a stud into the gun,
pressed the stud where it needed to go, and pulled a trigger. A big bunch
of sparks flew out and bobs'yer'uncle.

Anyone know anything about stud welding?

Grant Erwin
Kirkland, Washington



I rented a 1/2" capacity stud gun last fall to mount a railing on a
mezzanine.
It was a 400 amp machine, needed a lot of power.
I was shooting 1/2" diameter threaded stainless steel studs.
Worked great.
Only a few popped off later and I was able to TIG weld those, but
overall the stud gun saved me days of TIG welding.

I would love to own one, but they are a chunk of money.
You can rent them from a few places in town on a daily basis.

Seems like for what you need you could just stick weld them on with
6011.

"Ernie Leimkuhler" wrote in message
...
In article , Grant Erwin
wrote:

Back when I used to work in ships ('70s) I used to see the insulation
guys
laying out large numbers of stud locations, then the welders would move
in
with their stud guns and weld studs everywhere, then the insulation guys
would use the studs to hang insulation on the steel bulkheads and
overheads.

Now I want to make a clamshell forge, and I figure I'll need a few dozen
studs welded into the "shells" and wired together with heavy wire to
keep
the refractory in place. I don't own a stud gun nor, with the exception
of
my shipyard experience, have I ever seen one. I remember them being sort
of
like a spot welder except they were designed so you put a stud into the
gun,
pressed the stud where it needed to go, and pulled a trigger. A big
bunch
of sparks flew out and bobs'yer'uncle.

Anyone know anything about stud welding?

Grant Erwin
Kirkland, Washington


I once welded a washer to the end of a rod by starting the mig wire on the
rod inside the washer and doing a 'swoop' until the hole in the washer was
full. You could drill holes in the shell smaller than the rod you intend to
use and attach them the same way.

Joel. phx



I rented a 1/2" capacity stud gun last fall to mount a railing on a
mezzanine.
It was a 400 amp machine, needed a lot of power.
I was shooting 1/2" diameter threaded stainless steel studs.
Worked great.
Only a few popped off later and I was able to TIG weld those, but
overall the stud gun saved me days of TIG welding.

I would love to own one, but they are a chunk of money.
You can rent them from a few places in town on a daily basis.

Seems like for what you need you could just stick weld them on with
6011.

If 16 gauge mild steel studs are good enough this might work. Putting
a hook on the end of the stud might allow it to support the refractory
and still be protected by it.

http://www.harborfreight.com/cpi/cta...temnumber=3223

You might be able to make some studs from some more temperature
resistant material if necessary but it's hard to say if this gun would
have enough power.

You're welcome to borrow mine.

Cheers,

Kelley

On Tue, 20 Apr 2004 19:33:51 -0700, Grant Erwin
wrote:

Back when I used to work in ships ('70s) I used to see the insulation guys
laying out large numbers of stud locations, then the welders would move in
with their stud guns and weld studs everywhere, then the insulation guys
would use the studs to hang insulation on the steel bulkheads and overheads.

Now I want to make a clamshell forge, and I figure I'll need a few dozen
studs welded into the "shells" and wired together with heavy wire to keep
the refractory in place. I don't own a stud gun nor, with the exception of
my shipyard experience, have I ever seen one. I remember them being sort of
like a spot welder except they were designed so you put a stud into the gun,
pressed the stud where it needed to go, and pulled a trigger. A big bunch
of sparks flew out and bobs'yer'uncle.

Anyone know anything about stud welding?

Grant Erwin
Kirkland, Washington

Most stud welders are essentially capacative discharge welders. They
charge a large (and fairly expensive) bank of capacitors, then when you
push the button the power to them is disconnected from the supply and
they discharge through the stud to the workpiece. Capacitors discharge
AC so 99% of these machines are AC welders. Generally there is a
projection on the stud that hits first so that the arc is controlled to
form a molten pool of metal which the stud is pushed into. Sometimes
studs come with a flux ring in place around the projection to improve
things.

If you don't want the cost of a stud gun or rental on one, why not just
practice being bad at welding? It would seem that you could take a
simple AC buzz box and then attempt to make your electrode (wire or
whatever else you choose) stick to the base metal. With a pinch clamp
type electrode holder, you should be able to let go of the electrode
right away after it sticks. Get the amperage right for sticking and you
may get enough penetration that it will get the job done (at least the
damned things stick too much when you don't want them too!)

Koz

Grant Erwin wrote:

Back when I used to work in ships ('70s) I used to see the insulation guys
laying out large numbers of stud locations, then the welders would move in
with their stud guns and weld studs everywhere, then the insulation guys
would use the studs to hang insulation on the steel bulkheads and
overheads.

Now I want to make a clamshell forge, and I figure I'll need a few dozen
studs welded into the "shells" and wired together with heavy wire to keep
the refractory in place. I don't own a stud gun nor, with the exception of
my shipyard experience, have I ever seen one. I remember them being
sort of
like a spot welder except they were designed so you put a stud into
the gun,
pressed the stud where it needed to go, and pulled a trigger. A big bunch
of sparks flew out and bobs'yer'uncle.

Anyone know anything about stud welding?

Grant Erwin
Kirkland, Washington

On Wed, 21 Apr 2004 12:38:37 -0700, Koz
vaguely proposed a theory
.......and in reply I say!:
remove ns from my header address to reply via email

Capacitors discharge
AC so 99% of these machines are AC welders.

I have to question that. How would they discharge AC?
************************************************** **
I went on a guided tour not long ago.The guide got
us lost. He was a non-compass mentor.........sorry
.........no I'm not.

Shorted capacitors discharge an ac wave that degrades over a short time.
I can't specifically say why, but I assume that they sort-of re-charge
the opposite plate of the capacitor which then discharges kind of like a
swinging pendulum. Look up stuff on Tesla Coil design for more
information on this. The AC discharge is the basis of how a Tesla coil
works.

Of course I'm still half asleep this morning and am probably missing
something here.....

Koz

Old Nick wrote:

On Wed, 21 Apr 2004 12:38:37 -0700, Koz
vaguely proposed a theory
......and in reply I say!:
remove ns from my header address to reply via email



Capacitors discharge
AC so 99% of these machines are AC welders.



I have to question that. How would they discharge AC?
************************************************* ***
I went on a guided tour not long ago.The guide got
us lost. He was a non-compass mentor.........sorry
........no I'm not.

"Koz" wrote in message
...
Snip
Of course I'm still half asleep this morning and am probably missing
something here.....

It could've been put more succinctly, but yes that's the jist of it. :-)

Tim

--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

This sounds like a damped oscillation so the capacitor must discharge
into something like an inductor which would store energy and then
release some back to charge the capacitor again in the opposite
direction. There must be energy taken out of the system by resistance
(heat) or other means for it to fall to 0. Basically a capacitor is a
device to store electrical charge so at any given point its DC and
diesn't produce AC.

Koz wrote:

Shorted capacitors discharge an ac wave that degrades over a short
time. I can't specifically say why, but I assume that they sort-of
re-charge the opposite plate of the capacitor which then discharges
kind of like a swinging pendulum. Look up stuff on Tesla Coil design
for more information on this. The AC discharge is the basis of how a
Tesla coil works.
Of course I'm still half asleep this morning and am probably missing
something here.....

Koz

Old Nick wrote:

On Wed, 21 Apr 2004 12:38:37 -0700, Koz
vaguely proposed a theory
......and in reply I say!: remove ns from my header address to reply
via email



Capacitors discharge AC so 99% of these machines are AC welders.


I have to question that. How would they discharge AC?
************************************************** **
I went on a guided tour not long ago.The guide got us lost. He was a
non-compass mentor.........sorry
........no I'm not.

Yup, I was brain dead and had things crossed..that's the danger of
thinkin you remember something when your memory is really like swiss
cheese from eatin too many twinkies.

Interesting stuff came up while searching though....a process of
capacative discharge used for metal forming. Generally hobbyists use it
for "quarter shrinking". The huge magnetic field appears to shrink a
quarter in diameter without really messing up the coining. You get a
quarter that is thicker and smaller in diameter that still looks like a
quarter.

Interesting stuff if you search the web for "quarter shrinking"

Koz

David Billington wrote:

This sounds like a damped oscillation so the capacitor must discharge
into something like an inductor which would store energy and then
release some back to charge the capacitor again in the opposite
direction. There must be energy taken out of the system by resistance
(heat) or other means for it to fall to 0. Basically a capacitor is a
device to store electrical charge so at any given point its DC and
diesn't produce AC.
Koz wrote:

Shorted capacitors discharge an ac wave that degrades over a short
time. I can't specifically say why, but I assume that they sort-of
re-charge the opposite plate of the capacitor which then discharges
kind of like a swinging pendulum. Look up stuff on Tesla Coil design
for more information on this. The AC discharge is the basis of how a
Tesla coil works. Of course I'm still half asleep this morning and am
probably missing something here.....

Koz

Old Nick wrote:

On Wed, 21 Apr 2004 12:38:37 -0700, Koz
vaguely proposed a theory
......and in reply I say!: remove ns from my header address to reply
via email



Capacitors discharge AC so 99% of these machines are AC welders.



I have to question that. How would they discharge AC?
************************************************** **
I went on a guided tour not long ago.The guide got us lost. He was a
non-compass mentor.........sorry
........no I'm not.

I can sympathise with that, I sometimes re-read posts and wonder what I
was thinking of. Mainly just seems I could have put it better. I'll
check out the quarter shrinking, sounds weird but amusing.

Koz wrote:

Yup, I was brain dead and had things crossed..that's the danger of
thinkin you remember something when your memory is really like swiss
cheese from eatin too many twinkies.

Interesting stuff came up while searching though....a process of
capacative discharge used for metal forming. Generally hobbyists use
it for "quarter shrinking". The huge magnetic field appears to shrink
a quarter in diameter without really messing up the coining. You get
a quarter that is thicker and smaller in diameter that still looks
like a quarter.

Interesting stuff if you search the web for "quarter shrinking"

Koz

David Billington wrote:

This sounds like a damped oscillation so the capacitor must discharge
into something like an inductor which would store energy and then
release some back to charge the capacitor again in the opposite
direction. There must be energy taken out of the system by resistance
(heat) or other means for it to fall to 0. Basically a capacitor is a
device to store electrical charge so at any given point its DC and
diesn't produce AC.
Koz wrote:

Shorted capacitors discharge an ac wave that degrades over a short
time. I can't specifically say why, but I assume that they sort-of
re-charge the opposite plate of the capacitor which then discharges
kind of like a swinging pendulum. Look up stuff on Tesla Coil
design for more information on this. The AC discharge is the basis
of how a Tesla coil works. Of course I'm still half asleep this
morning and am probably missing something here.....

Koz

Old Nick wrote:

On Wed, 21 Apr 2004 12:38:37 -0700, Koz
vaguely proposed a theory
......and in reply I say!: remove ns from my header address to
reply via email



Capacitors discharge AC so 99% of these machines are AC welders.




I have to question that. How would they discharge AC?
************************************************** **
I went on a guided tour not long ago.The guide got us lost. He was
a non-compass mentor.........sorry
........no I'm not.

On Thu, 22 Apr 2004 20:27:21 +0100, David Billington
wrote:

This sounds like a damped oscillation so the capacitor must discharge
into something like an inductor which would store energy and then
release some back to charge the capacitor again in the opposite
direction. There must be energy taken out of the system by resistance
(heat) or other means for it to fall to 0. Basically a capacitor is a
device to store electrical charge so at any given point its DC and
diesn't produce AC.


The inductance is that of the single turn formed by the cables and the work.
It isn't much in Henrys, but it's still there.


Mark Rand
RTFM

On Thu, 22 Apr 2004 14:38:29 -0700, Koz
vaguely proposed a theory
.......and in reply I say!:
remove ns from my header address to reply via email

But are we getting AC, or pulsed DC, if there is no inductor involved?

If you had no reference point, pulsed DC looks like AC anyway, but

AH! We are talking welding. Do the caps go throiugh either a choke or
a tansformer? I have no idea. Either would produce AC, as the curren
rose and fell (magnetic field Out, magnetic field In Welding 1010
according to Homer G). I can see that.

I probably asked too fast myself.

Yup, I was brain dead and had things crossed..that's the danger of
thinkin you remember something when your memory is really like swiss
cheese from eatin too many twinkies.

************************************************** **
I went on a guided tour not long ago.The guide got
us lost. He was a non-compass mentor.........sorry
.........no I'm not.

"Old Nick" wrote in message
...
But are we getting AC, or pulsed DC, if there is no inductor involved?

Ah, but what are the wires connecting the capacitors to the work, and yes,
even the work itself?

Check out railguns too. They usually use large AC capacitors, because as
long as the slug is still inbetween the rails and the resonant circuit is
still ringing, there is still energy to be used. Last I heard, it usually
goes a few cycles before the slug leaves.

Tim

--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

On Fri, 23 Apr 2004 00:54:00 +0100, Mark Rand
vaguely proposed a theory
.......and in reply I say!:
remove ns from my header address to reply via email

OK. Is that enough to form real AC welding? I suppose under the
massive currents of a shorted cap, it could be.

It's all really old, but won;t the massive size of the cap, compared
to the very small inductance, affect this somehow?

The inductance is that of the single turn formed by the cables and the work.
It isn't much in Henrys, but it's still there.


Mark Rand
RTFM

************************************************** **
I went on a guided tour not long ago.The guide got
us lost. He was a non-compass mentor.........sorry
.........no I'm not.

On Thu, 22 Apr 2004 13:00:40 -0500, "Tim Williams"
wrote:

"Koz" wrote in message
...
Snip
Of course I'm still half asleep this morning and am probably missing
something here.....

It could've been put more succinctly, but yes that's the jist of it. :-)

Tim
Only works when discharging into a coil, guys. The cap stores DC, pure
and simple.

wrote in message
...
Only works when discharging into a coil, guys. The cap stores DC, pure
and simple.

So what are the wires leading to and from the cap?

Tim

--
"I have misplaced my pants." - Homer Simpson | Electronics,
- - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting
and Games: http://webpages.charter.net/dawill/tmoranwms

Daring to stick my food deeper into my mouth here.....because there is
some inductance inherent in any circuit, wouldn't any discharge product
ringing of the waveform to some extent? I seem to remember seeing
oscilloscope traces of shorting capacitors that showed a ringing
covering the notion that you had to make sure and control that or you'd
get all sorts of interesting results.

Oh yea...for those who missed it, I already admitted I was full o manure
in my previous statement so you don't need to flog the issue more

Koz

wrote:

On Thu, 22 Apr 2004 13:00:40 -0500, "Tim Williams"
wrote:



"Koz" wrote in message
...
Snip


Of course I'm still half asleep this morning and am probably missing
something here.....


It could've been put more succinctly, but yes that's the jist of it. :-)

Tim


Only works when discharging into a coil, guys. The cap stores DC, pure
and simple.

On Fri, 23 Apr 2004 14:36:01 -0700, Koz
vaguely proposed a theory
.......and in reply I say!:
remove ns from my header address to reply via email

But you _can_ spell hobbyist! G

Oh yea...for those who missed it, I already admitted I was full o manure
in my previous statement so you don't need to flog the issue more

Koz

************************************************** **
I went on a guided tour not long ago.The guide got
us lost. He was a non-compass mentor.........sorry
.........no I'm not.

On Fri, 23 Apr 2004 03:57:03 GMT, Old Nick postulated
that:-



OK. Is that enough to form real AC welding? I suppose under the
massive currents of a shorted cap, it could be.

It's all really old, but won;t the massive size of the cap, compared
to the very small inductance, affect this somehow?



f= 1/(2*pi*sqrt(L*C). It doesn't really matter whether they are similar sizes
or not for the resonant frequency. The important thing is that resistive
losses in the capacitors and cables (including Tan(delta) losses in the
capacitor insulation) are small compared with the loss across the joint being
made. You want the joint to get most of the heat!


PS. The capacitors themselves probably have fairly significant self inductance
as well.


Mark Rand
RTFM