[Otto Nobedder]

WP20 torch lead run almost continuously at 280A HFAC for 45 minutes...

GEDC1030.JPG (206.45 KiB) Viewed 1311 times

GEDC1031.JPG (183.86 KiB) Viewed 1311 times

Steve S

[Otto Nobedder]

Best guess...

Overheated the head, boiled the coolant, and vapor-locked the cooling system. The lead smoked instantly and blindingly.

Steve S

[Otto Nobedder]

Weling 11' of 4G Aluminum TIG, 3/8" 6061, in three passes.

GEDC1032.JPG (195.34 KiB) Viewed 1309 times

Comfortably, though... Here's my perch:

GEDC1037.JPG (208.01 KiB) Viewed 1309 times

Steve S

[Oddjob83]

lol the buckets are a nice touch, were you out of milk crates?

wasnt sure what i was looking at at first, it looked like the bottom of a fiberglass boat. are there no over temp sounds/beeps for the water cooler? or warning lights?

[Otto Nobedder]

Buckets were 4" taller than milk crates...

No, the cooler on this Miller 250DX has no interface with the main board. It happened too fast, anyway. By the time I thought to myself, "Why is the barrel on this torch getting hot?", someone was yelling and someone else pulled the disconnect to my welder. I lifted my hood to blinding, choking smoke, and steam erupting all along the lead.

Steve S

[Nils]

Don't mean to be a smarty-pants, but how do you get 280 amps out of a 250DX for one minute, let alone 45?

[Alumike]

I've smoked a couple wp 20's myself. I think duty cycle is 240 amps @ 100%. I never weld at more than 210 amps hfac. I think the 1st melt down was due to solinoid failure in the weldor. After that I hooked directly to the cooler and took the solinoid out of the loop. Not sure what caused the 2nd failure. 1st torch was a weldcraft. 2nd was weldtec. My meltdowns were not nearly so dramatic. Just hot water leaking out.

[TamJeff]

I have roached a couple cables like that. Usually on 1/2" material. In those situations, I have to use two machines and preheat, switching back and forth every 5 minutes of welding. With the flex lines, it will get balloon spots and burst the soft rubber. Also, the soft lines are prone to getting restrictions if even lightly stepped on, as does the gas lines.

In my mind, a 250 amp setup ought to be safe to around 275 amps, so that it would actually be a solid 250 amp rig. In other words, it ought to be able to handle 250 all day long. I have thought about just putting at least one machine with 300 amp setup but never bothered to inquire if this would help or hinder.

I would not care if it was physically bulkier. Seems that dainty stuff is all the rage these days and that performance is often the trade-off. Did you know, that there is a class of "men," who buy dainty fishing reels to keep from getting their wrists fatigued while fishing, of all things? HFC, man. That's just depressing. You know they have never held one of those all metal Milwaukee 9"rs all day. If so, they'd have to have a heavier reel just to keep from pitching the whole works over the trees on most days.

[noddybrian]

Wow - that's some quality damage - never knew it happened that fast - at least it looks like only the torch as you were on foot pedal - there was a previous post of a meltdown where it looked like the welding current went back up the switch leads to the set & damaged it - don't recall hearing how the guy got on.

I do like the "work platform" - your nearly qualified for farm jobs - just need to get comfortable with something similar on the edge of a grain store / slurry tank etc or tied to some old ladders ! - I used to like a pallet on the forklift for this type of work - but apparently this is no longer allowed as a forklift is not tested for lifting people ! gotta love those safety guys.

[Otto Nobedder]

Don't mean to be a smarty-pants, but how do you get 280 amps out of a 250DX for one minute, let alone 45?

The 250DX maxes at 310A, but short duty cycle. Go figure.

There was no sign of leakage before the burst. Between my "WTF?" and the pulling of the power disconnect, only about 4 oz of water were on the floor, and that was clearly stem-driven.

I will comment this... Once I flushed the stinky ruined coolant out and put "new" salvaged leads on the torch, the li'l whirlygig flow-indicator thingy was spinning a lot faster, so the original "superflex" may not have been flowing as well as it should. That's why I think I boiled the coolant in the head and vapor locked it.

Steve S

[TamJeff]

Don't mean to be a smarty-pants, but how do you get 280 amps out of a 250DX for one minute, let alone 45?

The 250DX maxes at 310A, but short duty cycle. Go figure.

There was no sign of leakage before the burst. Between my "WTF?" and the pulling of the power disconnect, only about 4 oz of water were on the floor, and that was clearly stem-driven.

I will comment this... Once I flushed the stinky ruined coolant out and put "new" salvaged leads on the torch, the li'l whirlygig flow-indicator thingy was spinning a lot faster, so the original "superflex" may not have been flowing as well as it should. That's why I think I boiled the coolant in the head and vapor locked it.

Steve S

I melted them at 250 amps. One with the Miller cooler and one with a Bernard, one with the synchrowave 250 and one with the Dynasty 300 DX. Not only that, it will do it every time at a continuous 250 amps for more than 10 minutes. I had no warning either. It never even had time to make the torch handles noticeably warmer than usual and I am not wearing gloves most of the time. Every time we have tried to do it, it melts cables. Somewhere I have photos that shows both grounds of both machines attached to larger weldments. It's not because of a random occurrence.

[MinnesotaDave]

I've recently started looking to upgrade to a water cooled torch.

From weldcraft:
Wp-20 100% at 250 DC and 180 AC

Wp-18 100% at 350 DC and 250 AC

Seems this would explain the melt-downs on the wp-20?

[nova_70_383]

if you do alot of this type of welding and at long periods, i highly recomend the weldcraft 18 supercool torch. i use this very torch where i work. i weld everyday at 300 to 400 amps. i cant say enough on how well this torch holds up. the whole torch head is water cooled so it never gets more the warm. one thing that is unique to the supercool compared to the standard 18 is the cups are gas lens cups even if you use a standard collet. its super easy to change to a gas lens, but the only draw back is the large 1" dia gas lens are not avlailable for the super cool. if you have any other questions please ask. hope this helps.

[Otto Nobedder]

Interestingly, I'd been welding above 250A AC for a day and a half on the wp-20 with no issues. I keep my arc-balance at 9 for heavy sections like this, and weld for 10 minutes at a stretch, minus rod-changes.

I suppose, since I had less than an inch of root-pass left when it blew up on me, I was "in the home-stretch" and pushed it past that ten-minute mark that had protected me 'til then...

The next day, with the fresh torch leads, I blew a 50A fuse on a 460V circuit with 3" of cap-pass left...

Steve S

[NT Unique]

I've blown a few leads now myself on my WP20 torch, I had a aftermarket cooler though. First time I'd forgotten to turn the cooler on, second time was welding long seam welds on boat hulls. After three days of welding in 40+ deg C heat the outlet line was ballooning. Next day it went off like a flat tyre, I knew about that one, bloody coolant all over the workshop. I ended up re-routing the outlet into an alloy 1 gallon type tank with baffles which then goes to the cooler. This helps take the head pressure off the outlet line, and the alloy baffled tank helps remove a fair amount of the heat before it goes through the cooler. Been spot on for some time now.

Not trying to take anything away from you Steve, cause that's an almighty fine effort you have there A1 mate

Cheers

[Otto Nobedder]

Oddly, the coolant in the reservoir was barely warm.

I found, when I replaced the supply and return lines, I had much better flow (The Miller cooler has a whirly-gig indicator on the return side) so I may have had a restricted line in the first place contributing to the problem.

The stand-alone system in this new 250DX has the advantage of running continuously, where the integrated system in our older machines would shut down several seconds after the arc stopped. The older machine, with the integrated system, had the advantage of shutting down the arc (and throwing an error code) if the flow was disrupted.

For maintenance, I prefer the new system. You can slide it out, clean the fins, plug it in and flush the system, and the filter is readily accessible.

Steve S