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View Full Version : mitech 250 s tig welder

down19992000
12-01-2007, 02:14 PM
i am having a problem with a new mitech dc only tig welder i bought i have to run the gas at around 55 cfh to get a decent weld if i dont run it that high i just get air (porosity) in my welds i have tried every place from 5 cfh up to 55 cfh before i stopped getting the air in my welds. anyone have any thoughts as to why it is doing this? i know its not the regulator because it is the same one i use for my mig welder and it does fine on it at about 20-25 cfh.
coldlap
12-02-2007, 05:36 PM
Have you checked the torch some times the torch head is loose inside the handle or back cap has a poor seal:waving:
down19992000
03-07-2008, 01:30 PM
i found out what was wrong i took apart the solenoid and it had rust or some other kind of powdery substance in it. i cleaned it out and reassembled and its working great
trscott
03-13-2008, 02:53 PM
i found out what was wrong i took apart the solenoid and it had rust or some other kind of powdery substance in it. i cleaned it out and reassembled and its working great

I don't suppose you took any pics of the powdery substance? I would be curious to know what that was. Do you think it could have been salt corrosion from shipping? Do you happen to remember if the packaging had any dessicant packs in it? Was there a good plastic wrap around the internal packaging?

If the package was well sealed, and had desicant packs inside, then it suggests to me that the corrosion might have occurred before it was packed, perhaps even before the solenoid was built into the welder. In other words it could have happened during shipping of the solenoid parts to the welder mfr. This may suggest that they aren't testing the units before shipping, or that the testing is too cursory.

You know what would be a cool business decision by one of these Chinese welder companies, in order to differentiate themselves as a more conscientious manufacturer? If they shipped a small weld coupon with each unit shipped, just a small demonstration that they tested it before shipping. I'd sure pay $5 extra for that. I have an old S&W K22 revolver that my grandfather bought years ago and that came from the factory with a target bullseye that had a tight 5 shot group.