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> Are There Differences in AC Welders?
post Nov 25 2017, 08:10 PM
Joined: 25-Nov 17

I normally TIG weld steel & stainless on DC
In my shop we have 3 TIG machines

Linclon Squarewave ACDC 401 older than 1992 I've been told
Murex 251 transtig ACDC about 10 years old
Thermal Arc 201 ts DC only - This is the machine i use mainly - its about 4 years old

Between these machines on DC I notice big differences -
The Lincoln is slow to strike up compared to the others.
The Thermal Arcs Arc is so much more stable at any amps up to 200 which is its max.

I haven't used many MIG machines - Only 2 - but there are big differences in feel to me.

we weren't so busy last week so i decided to try my hand with AC on Aluminium

I was Making a table out of 2"x1"x1/8" box section.

And I had no problem using the Murex with the butt joints (deep 3mm V) in getting a nice smooth glossy finish.

I decide to use this welder because the AC Balance & Frequency are both adjustable.
Whereas the Lincoln only has adjustable Balance control & plus it was being used by another guy.

However when I came to weld some triangle corner lugs flush with the top of the table is when I had problems.

These corner lugs were 3/16" thick. I don't know the grade of any of these materials - Perhaps i should.

But on the same settings the Tee Joint welds came out grainy, lumpy, the arc was horrendously unstable & the 3/16" melted away when the box section didn't even get hot.

So I ditched the Murex & used the Lincoln - The arc was more stable - the weld was not glossy.
at least both materials melted. but they were still somewhat grainy.

These two welding machines are not looked after at all. hardly cleaned, sparks fly into them, torches burst, gas regulators are dropped.

I look after my thermal arc & performs faultlessly.

My question is:

Can a welding machine be the cause of My poor welds in the corner lugs or is it just the user in my case??
Also can two welding machines produce completely different outcomes?? - Assuming User is the same.

Any help would be greatly appreciated

Technic Al
post Nov 26 2017, 03:07 PM
Joined: 14-Oct 03

One possibility could be that whilst the settings appear to be the same, in truth they are different. The machines dont sound as if theyve been calibrated. Id suspect the balance setting.
post Nov 26 2017, 06:23 PM
Joined: 25-Nov 17

Iím 100% sure they havenít been calibrated. - Like Ever!!
Iíll put this to my gaffa but I can guarantee he wonít care much.
Cheers for the reply
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