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calcustom
08-06-2011, 11:03 PM
I have a little harbor freight buzz box and was wondering what results I would have if I reversed the polarity.
Has anyone done this?

calcustom
08-06-2011, 11:51 PM
I may not be using the right description.
I am wondering results from having the electrode negative.

Ibedayank
08-07-2011, 02:32 AM
electrodes are made to burn only one way... that is why you can NOT reverse the cables on a ac arc welder and it wouldn't matter even if you did as AC means alternating current.
reversing current only happens when using a dc welder

John Lewis
08-07-2011, 08:57 AM
I accidently reversed the polarity on my little dc welder when making the Marauder.
I wondered what was wrong. Thought the power might be low. Screwed up the amps etc etc. The welds stayed atrocious.
I was getting bird droppings, burning holes, anything but a neat weld.

Then the penny dropped.

No harm in trying it on a piece of scrap if you want to see what happens.

John

lanzecki
08-11-2011, 05:00 PM
If you have an AC welder it won't matter.

If you have an inverter type welder and you are stick welding (Arc, MMA) you'll need DCEP (DC electrode Positive to get good welds as John spoke of.

Mig welders are DCEP as well.

Having the electrode Positive results in the electrons flowing in the right direction and the electrode (welding stick or mig wire) getting hot enough to weld. The heat from this transfers onto the piece you are welding.

The Only welders that use DCEN (Electrode Negative) as a matter of course are DC TIG welders. As the electrode is not used in the welding process like ARC and MIG The electrode is generally Negative. This results in lower temps on the tungsten saving the tungsten from overheating and melting.

We won't comment on AC TIG, that's another story. But interesting if you are a geek like me :)

trikeman
08-11-2011, 07:44 PM
It depends on what rod you are using. Some rods will run electrode positive, electrode negative, or even AC. Others are designed for just one. Look up the specs on whatever rods you are using. Electrode negative will give you deeper penetration and a narrower bead than electrode positive, and sometimes you want that. Other times you want shallow penetration and a fat bead.

calcustom
08-12-2011, 12:01 AM
Im using E6013 in 1/16 and 3/32.
I am using 1 of the little DC inverter welders from Harbor Freight. (http://www.harborfreight.com/welding/arc-welders/80-amp-inverter-arc-welder-91110.html)
In the description of the unit it stated "DC output current allows soft fusion for good penetration. Change polarity between DCEN (+), and DCEP (-)."
I started searching to find out what the polarity changes would do and found this. (http://www.millerwelds.com/resources/calculators/stick_amperage_calculator.php)
This gave me a few answers and raised a couple more....lol

Ibedayank
08-12-2011, 07:06 AM
If you have an AC welder it won't matter.

If you have an inverter type welder and you are stick welding (Arc, MMA) you'll need DCEP (DC electrode Positive to get good welds as John spoke of.

Mig welders are DCEP as well.

Having the electrode Positive results in the electrons flowing in the right direction and the electrode (welding stick or mig wire) getting hot enough to weld. The heat from this transfers onto the piece you are welding.

The Only welders that use DCEN (Electrode Negative) as a matter of course are DC TIG welders. As the electrode is not used in the welding process like ARC and MIG The electrode is generally Negative. This results in lower temps on the tungsten saving the tungsten from overheating and melting.

We won't comment on AC TIG, that's another story. But interesting if you are a geek like me :)
ac tig .... needed to tig aluminum
dc just don/t do the job as nicely or as easy