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Thread: MIGS, TIGS & Magnets
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19th Apr 2021, 04:38 PM #1
MIGS, TIGS & Magnets
Today I was trying to TIG up small mild steel bracket that I had supported from behind with one of those magnetic squares and I was trying to get a bead on the other side of the bracket. For the life of me I could not get the arc to sit anywhere near the joint. After a few tries I was thinking what metal have I used that is making the arc behave so erratically. I thought bugger this and got the MIG onto it and although it too struggled at first to lay down a bead where I wanted it, got a very big bead down and although it was ugly as sin, the job was done. Reflecting some time later, I figured it must have been the magnetic field from the square that was playing havoc?
He Who Dies With the Most Tools Wins
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19th Apr 2021, 04:51 PM #2Most Valued Member
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Yes, it happens. PITA and I’ve pretty much stopped using magnets for that reason.
Steve
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19th Apr 2021, 05:10 PM #3Philomath in training
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Likewise. I'll use them to hold 'the other corner', but not the one I'm trying to weld if I can at all help it.
Michael
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19th Apr 2021, 07:06 PM #4
It's called 'Arc Blow'. Common around magnetic fields.
There are some tricks, you can buy dedicated degaussing machines to de-magnetise materials, but in your instance it's introduced magnetism, so remove it from the equation.
I've also heard you can wrap the earth clamp cable around the workpiece to introduce an opposing eddy current... but never tried it.
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20th Apr 2021, 11:26 PM #5Diamond Member
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Well, I didn't know that would be a problem!
I was planning using some magnets to hold steel projects.
Guess I'll have to use something else, or keep it as far away as possible.
Thanks for the 'heads up'
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21st Apr 2021, 12:57 AM #6
Hi Steve, Guys,
A magnetic field is some times used in circuit breakers and is designed to blow the arc away, extinguishing it, when the contacts open.
All currents flowing in a circuit or through an arc produce a magnetic field that can be influenced by another magnetic field.Best Regards:
Baron J.
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