FrankenTig Miller HF-251D + DC Buzzbox + SCR power control, gas solenoid question

So that's what I've got set up. Literally a montgomery ward AC/DC buzzbox with output leading to an HF251D that I picked up dirt cheap. In the process I also have a Powertronics SCR that controls one leg of the welding transformer for my pedal.

It works pretty good, but my gas useage is not what I would consider acceptable. The solenoid on the HF251 is set up so that as soon as you turn the machine on, the gas flows. This gets a tad bit expensive.

I am thinking about adding a couple relays so that the gas only flows when the pedal is depressed. I will basically use the remote switch, or use one of the extra connectors on the 14 pin connector. Ultimately, I would like to have a post flow delay as well.

I'm just curious if there is any reason why I should continue to let this thing drain my tank, even when I'm not really actively welding and just have the machine on. (ie, what am I missing, this seems ignorant to me that it's wired this way)

And as long as I'm asking. Anybody know what the pedal wire is? It's a neoprene jacket, 20 gauge conductor, but I'm having trouble finding something that I know will be equivalent. I like the flexibility, but may end up needing another 2 conductors. I thought it was just a SJEOW, but I cannot find 20/5 (or 20/7 for that matter)

Torch heads with shut off valves are available.

snowman said:

I cannot find 20/5 (or 20/7 for that matter)

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Here's a search link for such cable at Mouser. Unfortunately, they don't sell by the foot. The search results are for 100 foot spools.

It's not the same cable.

I'll just add a purge switch to the cable...just have to figure out if I have extra amphenol pins.

snowman said:

And as long as I'm asking. Anybody know what the pedal wire is? It's a neoprene jacket, 20 gauge conductor, but I'm having trouble finding something that I know will be equivalent. I like the flexibility, but may end up needing another 2 conductors. I thought it was just a SJEOW, but I cannot find 20/5 (or 20/7 for that matter)

Click to expand...

I used to get the cable for foot pedals from a local supplier. I just bought it by the roll, though.

Mcmaster will have what you need. Look at the continuous flex cable.

McMaster-Carr

My HF-251 D only turns on the gas when the pedal is depressed, so of course yours can do that too, assuming you wire your pedal accordingly.

I often scratch start tig on jobsites, using a rented Trailblazer or similar gas drive machine- so I have a tig torch with a built in valve on the torch handle, as well- that works, but you tend to forget to both turn it on, and turn it off, til you get used to it.

You need a contacter that shuts off power to the welding machine but not the cooling fan.

That way the tungsten will not be energized when in the off position.(save your eyes)

Should be a micro switch in the foot pedal plus the pot.

Also I quit messing with amphenol plugs a long time ago much easier to just solder and shrink wrap.

I seems like I get better control of my amps that way .

Should put an adjustable time delay on the gas selinoid also.

Thanks Ries...looking at the schematic it should definitely be controlled.

I imagine the post flow timing relay is shot, those damn things love to fail! I've hopefully got a spare, otherwise I'll be rigging up a post flow timer.

I'll jumper one of the two tomorrow and figure out which part is bad.

When I built my HF box I used a IDEC delay off timer. Cheap off ebay. Way cheaper than the miller stock unit. Those were around $200.

I wouldn't use the miller unit either way. I've got a couple SSR timing relays around somewhere, if not I'd rig somethign up.