Lincoln Tig 355........

By BC3 Date 08-06-2005 02:54

Hi fellas, Im new to your site but an old timer to the trade. The question I have is about the Lincoln Tig 355 machine. I bought it new
in 1993 and haven't had any real problems with it except for an intermit
tant high freq. problem.....The pre flow is set all the way at 0 and
when you first hit the pedal (dcen) it still takes a second before you can get welding. after about 20 minutes of steady welding it starts losing
the high freq. and you almost have to scratch the tungsten to the work piece to establish and arc.....then it welds fine.....what do you think is the problem? I have the machine grounded to a 8 foot rod in the ground
outside.....even if I turn the high freq knob all the way up it still acts up
I love the welder with all the bells and whistles.....maybe thats the
problem.......too many whistles...http://img.photobucket.com/albums/v93/billcalicura/bcshop.jpg

B.

By Lawrence (*****)

Date 08-06-2005 03:31

After 20 minutes of straight welding it's time to re-sharpen your electrode... Problem solved!

Those tungstens have rare earth alloys doped into them. Those "emitters" will eventually migrate from the tip and you will need to re-prep the end. Also sometimes a little oxide will form on the end of your tungsten if you pull it quickly away from the puddle after the arc is broken. A short post flow and a slow draw back will help there.

When you "scratch" your poor performing tungsten, you take a little of the used up tip off your electrode and break off some of the oxide. The bad part is your leaving tungsten where ever you have scratched.

By BC3 Date 08-06-2005 18:18

I'll give it a try......