DCEN DCEP & AC question.

[heinz57]

Just watched a video on youtube entitled - tig welding (Preston College). Good video but its left me with more questions. With the welders that ive been using at college, there appear to be only 2 settings, AC & DC. In the video he has 3 - AC/DCEN/DCEP, activated by a lever switch. I understand the balance function:- more EN versus less EP for example but i was under the impression that this was just for Aluminium/mag. What metals would you weld with DCEN and what would you weld with DCEP? Are the 2 settings to do with penetration?

Totally confused, .

 

[shenion]

TIG is almost always either DCEN or AC. DCEP is used rarely and usually only when you don't have AC.

I did use DCEP on some very thin metal to try and reduce the heat.

The balance is only for AC.

The DCEP position would be used for arc welding.

 

[GrahamGKD]

The way I understand it DCEP would burn out the tungsten pretty quick if used for TIG. Graham.

 

[shenion]

The way I understand it DCEP would burn out the tungsten pretty quick if used for TIG. Graham.

Yes, I have forgotten to switch polarity back when moving from arc to TIG.

The tungsten melts back like a fuse

You need a huge tungsten to do anything in DCEP.

 

[Windy Miller]

Yes, I have forgotten to switch polarity back when moving from arc to TIG.

The tungsten melts back like a fuse

Yep sure does! Did it myself at the weekend!

 

[heinz57]

Shenion, thanks for explaining that, i had no idea that DCEP was used on stick welding, thankyou to Graham also, i think i'm going to save a fair bit of class time now that i won't be grinding tungstens so much, cheers fellas!

 

[Omniata]

I spoke to a guy about a week ago that knows a guy that does TIG on stainless using DCEP, he doesn't use anything else "apparently" and has been known to say it's the only propper way to TIG stainless

 

[hotrodder]

Tungsten diameter versus amperage and polarity

 

[heinz57]

Nice one Hotrodder, good resource!

 

[heinz57]

I spoke to a guy about a week ago that knows a guy that does TIG on stainless using DCEP, he doesn't use anything else "apparently" and has been known to say it's the only propper way to TIG stainless

Interesting, i was TIG welding stainless last night and found it very easy to burn through. I was using 2mm steel and was down to 55amps in the end. I'm wondering what would happen if i switched to AC and tried it. I know you need to back purge "mirrored" stainless steel but as these are only training pieces im now interested to see what would happen on AC. Any comments appreciated.

 

[shenion]

I've done regular steel on AC (forgot to switch polarity.) Worked fine but there is more of the etching caused by stray arcs.

 

[Delgado]

Interesting, i was TIG welding stainless last night and found it very easy to burn through. I was using 2mm steel and was down to 55amps in the end. I'm wondering what would happen if i switched to AC and tried it. I know you need to back purge "mirrored" stainless steel but as these are only training pieces im now interested to see what would happen on AC. Any comments appreciated.

2mm 304 Stainless, 45 amps, AC freq 100hz, balance 50%, 1.6mm 308 filler and 2.5 zirc tungsten.





Do-able (probably more so with practice) , but not pretty by any stretch of the imagination

 

[heinz57]

Interesting pics. Cheers matey!