the_fbi
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| posted on 29/9/07 at 02:42 PM |
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Welding polarity, a lesson learned.
Few weeks ago my trusty arc welder died, nothing wrong connectivity wise, just the coil breaking down it would appear.
So I bought a cheapy invertor (previous thread http://www.locostbuilders.co.uk/viewthread.php?tid=73301 ) and was slightly purturbed at the welds I
was getting.
I didn't spend much time with it, as I had no current need to use it, but after 30 minutes playing with both mild and stainless I concluded that
either I'd totally lost my touch, or that the rods were damp and ruined.
The other day I read thread where somebody mentioned that on an inverter you reverse the polarity for arc compared to tig.
Remembered this earlier and thought I'd just go check that I had actually connected the leads correctly.
Unfortunately I hadn't. I've always assumed the earth clamp is exactly that, and earth/ground/-ve clamp. Clearly with arc this isn't
the case. The clamp is actually +ve!
I know the front of the welder (shown in other thread) clearly shows the earth clamp picture next to the +ve connection, but I'd just looked at
the + and - pictures and connected accordingly.
So, after changing the electrode holder and earth clamp around, I now have this as a result.
 
Inv. Weld Test
Thats a 2.5mm (perhaps 2.1mm) rod, on 82 amps in the filleted corners created between 2 pieces of 20mm shs.
The slag just fell off, as it should, and the top of the weld is flush with the steel.
Photo isn't great, but its a nice weld 
Given I've got to weld a a couple of flanges onto a cat and a cat bypass next weekend, in stainless, I'm glad its all working as it should
be.
Chuffed
[Edited on 29/9/07 by the_fbi]
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BenB
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| posted on 29/9/07 at 03:19 PM |
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Show off
Looks good!
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zilspeed
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| posted on 29/9/07 at 03:59 PM |
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Just read your previous thread and he is listing these inverters again.
Good prices.
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the_fbi
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| posted on 29/9/07 at 04:20 PM |
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Last I saw he was listing 75 or 70's, not 105's ?
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Mark.
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| posted on 29/9/07 at 05:48 PM |
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Now try doing that hanging off scaffolding in the rain vert welding pipe
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gazza285
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| posted on 29/9/07 at 06:07 PM |
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With low hydrogen rods.
DO NOT PUT ON KNOB OR BOLLOCKS!
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