Lincoln Ideal Arc Tig 250 AC Issues

Hi all

I know many of you guys have this TIG welder at home and hopefully you can help me out. When I try to run the AC on this the arc is only on for half the time. The power is only on for about 1-2 seconds, then fades to nothing, then starts up again, and repeat over and over. Diode out? If so where are they located (pictures would help), easiest way to get to it? I downloaded the manual and the pictures look like some 1st graders art project. Also what arc gap should i have? I am new to this machine. All pointers and help would be immensely appreciated. Thanks.

i have this machine.

which process? stick? tig? are you using the remote pedal? controlling current at
the machine ? or with the pedal?

what does it do when you DC tig weld with the switch set to " HF start only ?
what does it do when you AC tig weld with the switch set to " HF ON ?
what does it do when you AC stick weld with the switch set to OFF ?

i don't know , but don't diodes usually rectify the AC to get DC?

the spark gap should be stamped by the little access plate . i think mine says
.008 or .010 i really don't remember .

do you have a photo of YOUR machine .
we can't tell much from that 3-year old stock photo.

Tnmgcarbide

i have this machine.

which process? stick? tig? are you using the remote pedal? controlling current at
the machine ? or with the pedal? TIG, Foot Pedal

what does it do when you DC tig weld with the switch set to " HF start only ? I'll try it tonight when I get home
what does it do when you AC tig weld with the switch set to " HF ON ?I'll try it tonight when I get home
what does it do when you AC stick weld with the switch set to OFF ?I'll try it tonight when I get home

i don't know , but don't diodes usually rectify the AC to get DC?

the spark gap should be stamped by the little access plate . i think mine says
.008 or .010 i really don't remember . I'll try it tonight when I get home

do you have a photo of YOUR machine. I'll take one tonight
we can't tell much from that 3-year old stock photo.

OK I finally got back to playing around with it. I had the spark switch on "start only" vs "on" for aluminum. I finally was able to put some beads down. I worked as a mig welder in college, was taught by a boiler maker on arc welding but have only used a tig welder a couple times. The few times I did use one it was already setup and ready to go, which as we all know the setup is huge. With that said I have questions I hope to help shorten my learning curve. If they seem stupid, it's because I don't know the answer yet, please humor me.

1. Spark gap. Mine says set to .040". What does it do? What do you have yours set at? What happens if it is smaller or larger?

2. Tungsten type. What is your goto tungsten for steel? Aluminum? Stainless Steel? I've read up on the types but many are good at a bunch of materials.

3. Tungsten stick out. How much? Will it make a difference for fillet vs butt joints? I think it would. If so how much? Tip preparation. DC positive and ball the tip?

4 Afterflow timer. Set it and forget it? or do you adjust for application?

5. Current Range selector. Do you just set to high and use the pedal to control your output? Or is there an advantage using the lower settings, maybe for thin materials?

6. Current control. Is this only used for Arc welding?

7. Gas flow. The output on mine is pressure regulated vs flow regulated for others. What should I set the pressure at? Or should I get a flow regulated version. Again settings for flow? What are warning signs the gas is getting a little low. Obviously if it's really low the weld oxidizes and goes to crap but is there any other warnings?

Notes: I have a dedicated stainless brush for the aluminum and I brush the crap out of it before welding. You can see the difference

Below is my actual machine and the settings I was running doing the last run of aluminum.
Thanks for your time.

Check out this booklet that Miller publishes on TIG welding. (GTAW)

Welding Training Resources - MillerWelds

Idealarc 300-300 I had, had a spark gap setting of .008-.010 as I recall.
.040 sounds hugely wrong
Lincoln should have an owner's manual for your machine, as free download.

I have the manual for the Lincoln Idealarc 250/250 TIG. It is still online at the Lincoln Website. The manual number is IM-315A, February, 1997. On page 14 there is a diagram of the points for High Frequency. It shows .040 max. I would think that's rather large, but that's what it says.

Newman109 said:

I have the manual for the Lincoln Idealarc 250/250 TIG. It is still online at the Lincoln Website. The manual number is IM-315A, February, 1997. On page 14 there is a diagram of the points for High Frequency. It shows .040 max. I would think that's rather large, but that's what it says.

Click to expand...

Set towards the minimum for easier arc start and maintain, but first look at point condition,
after lots of use they tend to get pitted, etc.
take 'em out and flat file, etc. to clean up.