Tell me about my old Miller setup

[pvfjr]

I just scored a Miller Dialarc 250 for $300. It came with a spool gun, tig torch, HF box, flow meter, and foot control. Lots and lots of wiring too.

I tried to do a little research about the external HF boxes, but only found info on the HF-251. This turned out not to be an HF 251, but seems similar. I did notice it's an old spark gap style, but he said he'd adjusted them and had it up and running a while back.

Until now, I only had a 110V Lincoln 3200 "HD" that tops out at 90 amps with a low duty cycle, so I'm excited to have a real machine now.

So what can you guys tell me about these things? I'm not even sure how it all ought to be hooked up. I think a manual for the HF box would probably be the first thing I'd need.

Also, there's a toggle on the front panel of the Dialarc, with hand-drawn labels that read "Spool Gun" or "TIG". I'm not sure what this does...

 

[pvfjr]

Here are some pics

 

[sberry]

I would say someone worked on this gem to allow the use of a spool gun. Millerwelds has manuals free on their site for it. 300 for it is a score.

 

[dr_clyde]

I don't think those were set up from the factory to run a spool gun, as wire welding is a constant voltage process and the dialarc is a constant current machine.


However, they are old tanks and seldom wear out. Get a HF box so you can do TIG without scratch start.

 

[welder4956]

This looks like a modification someone did and you probably won't find anything in an owner's manual on it. It looks like the toggle switch and the twistlok panel connector for the foot control were added. But the old Miller foot control usually has 2 leads, one 2-prong lead for the contactor on/off and a 3-prong lead for the varistor that controls amperage. I think the toggle may bypass the amperage function of the foot control so that the amp setting is controlled by the dial instead of the foot control. The machines that came standard with a foot control had a remote on/off switch. I think this switch may do the same thing.

The WC-III control for the spool gun has a voltage sensing lead that clips on the work and supports either constant current or constant voltage machines. Your Dialarc is a constant current machine. The WC-III control also has it's own contactor for the spool gun, which is needed since your model did not come with a contactor. There are other models of the Dialarc that did have a contactor, such as the Dialarc HF. These are good, reliable machines and use single phase input power.

 

[welder4956]

Here's some links for you.

WC-III Control Box: https://www.millerwelds.com/files/owners-manuals/O1084C_MIL.pdf

High Freq Box: https://www.millerwelds.com/files/owners-manuals/O610A_MIL.pdf

Dialarc 250 AC/DC: https://www.millerwelds.com/files/owners-manuals/O314C_MIL.pdf

 

[Tinner]

If in good shape, a Dialarc is a decent TIG/Stick welder. The current is pretty smooth and stable. I'd rate them a notch below a Synchrowave or a Lincoln Square Wave machine. Better than most old stick welders when used for TIG. Not even close to a modern inverter.

A good Dialarc 250 is certainly worth up to $500, so you did alright.

I know nothing of the spool gun setup, as I avoid them like the plague. If it works, consider it a bonus.

 

[zkling]

Welder4956 is right on. Back in the day they were connonly put together like that as a general shop unit. Now a days they are a bit antiquated, but the diarc is still a great stick and DC tig welder.

 

[pvfjr]

Get a HF box so you can do TIG without scratch start.

It came with one (the gray box on top).

The WC-III control for the spool gun has a voltage sensing lead that clips on the work and supports either constant current or constant voltage machines.

I think I saw a wire with a small clip on it that I was wondering about. That must be it. I'll have to read up on this. I never knew that wire welders were constant voltage. It seems like that would be difficult to control when you're intentionally creating a short circuit. I always just assumed that constant current was the way to go.

But the old Miller foot control usually has 2 leads, one 2-prong lead for the contactor on/off and a 3-prong lead for the varistor that controls amperage.

I read somewhere that the Dialarc HF foot control did NOT control current, but just switched on the gas and triggered the HF start. I assumed this one is similar, but it sounds like there's a chance that the foot control also controls current? That would be sweet! I was talking to a friend who had foot control over his arc welder, and he made it sound like the best thing since sliced bread (not to mention the TIG convenience).

I thought I was going to have to bypass the dial myself and modify this unit, but maybe I won't have to. I'll have to take the foot pedal apart and see what's in there (besides the rattling screw I'm hearing).

The WC-III control also has it's own contactor for the spool gun

That's good to know. I was wondering if I'd have to contend with constant-hot mig wire. Do you think I can run the HF box through the contactor box as well? Wouldn't that be a bit of a benefit?

I know nothing of the spool gun setup, as I avoid them like the plague.

Why is that? I know I can expect it to be clunky and awkward, any other reasons? I'm hoping this can pick up where my 3200 HD leaves off (>90A for a minute).

 

[sberry]

I don't have experience on CC feeders but there may be some parameters that make it dfiferent than the CC especially for adjustability. It might be as good as an inverter. May have better starts than some of them with safety low ocv.
I have a Maxstar, I actually give the edge to my DC buzzer in starts and run the same as the Max once the arc starts.