what is involved in 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.

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

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

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

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...

**************************************************** 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 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.

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

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.

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

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 Erw> Back when I used to work in ships ('70s) I used to see the insulation guys

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

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:

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

Tim

-- "I have misplaced my pants." - Homer Simpson | Electronics,

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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 Bill> This sounds like a damped oscillation so the capacitor must discharge

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 ). I can see that.

I probably asked too fast myself.

**************************************************** 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.

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,

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