2T vs 4T, a tack weld problem on my TIG

[carbon]

if the tungsten changes colour due to lack of shielding when it cools

Ignore this part, post flow controls the gas flow.

 

[carbon]

Maybe that’s the problem, when in 2T mode I need to lower the down slope as it would not switch off on the release

How long is the down slope time?

 

[addjunkie]

Maybe that’s the problem, when in 2T mode I need to lower the down slope as it would not switch off on the release

You still need some down slope to make sure you get a decent tack, argon flow is essential to protect both the weld metal and the tungsten electrode from contamination, oxidation, and damage while they cool

 

[doubleboost]

Ive never tried this but would have thought that the up slope and down slope would need to be very short for this to work with 2T

2T is just on and off no down or up slope that is a feature of 4T

 

[carbon]

Down slope is enabled in 2T on this thermal arc as shown in the manual

My thermal arc 250 also has similar operation with downslope in 2T

 

[Hitch]

Set it to 2T, HF, turn all up slope and down slope to 0 secs and try it. Leave a few seconds of post gas.

Arc should be ignited until you release the button.
The dial should simply adjust amps up/down id say.

If that works as expected, put it onto 4t. Press and release to initiate arc, press and release to stop.

It should stop immediately.

Introduce a second or two downslope and look at the effects.

Now some machines had additional functions on 4t, for example, pressing and holding whilst welding will drop machine to half power on some Migatronics for example, or a standard press and release will stop arc normally with whatever downslope is set.

 

[northwest]

I went 'round @Bluemotion 's gaff this morning. His TIG set absolutely has an issue, in 2T mode it just wouldn't let go and releasing the button changed nothing, for a duration only the welder decided. It was most disconcerting. We have both decided that getting the set to an engineer or getting the engineer to come to the set was the way forward. When it did work it worked okay, but it absolutely needs the control knob looking at, every setting was a variable that seemed to change on the fly.
Anyway, on the bright side it has given me the impetus I need to get cracking with Samantha so that's my next move, having temporarily given up looking for a box for @Dcal 's shipment.

 

[addjunkie]

I went 'round @Bluemotion 's gaff this morning. His TIG set absolutely has an issue, in 2T mode it just wouldn't let go and releasing the button changed nothing, for a duration only the welder decided. It was most disconcerting. We have both decided that getting the set to an engineer or getting the engineer to come to the set was the way forward. When it did work it worked okay, but it absolutely needs the control knob looking at, every setting was a variable that seemed to change on the fly.
Anyway, on the bright side it has given me the impetus I need to get cracking with Samantha so that's my next move, having temporarily given up looking for a box for @Dcal 's shipment.

Have you tried a different torch?

 

[Bluemotion]

With a big thank you to @northwest for his time and help and brilliant conversation as we discovered the main machine is faulty at this point as it’s running like a bull in a china shop. Phase 2, To be continued………

 

[Turbo]

If you haven't done it recently can I suggest that you open up the machine and blow it out. When I got my used thermal arc it was filthy inside and I had to use electrical contact cleaner and a brush to clean the dust build up off the circuit boards.
This could be enough to get it working again.

 

[Bluemotion]

If you haven't done it recently can I suggest that you open up the machine and blow it out. When I got my used thermal arc it was filthy inside and I had to use electrical contact cleaner and a brush to clean the dust build up off the circuit boards.
This could be enough to get it working again.

Yes probably the best thing to do first. I quite like cleaning and servicing and it might help the problem solving

 

[Munkul]

Thermal arc machines sometimes get stuck in a stupid logic loop when you have a pedal or a amptrol plugged in. Can you unplug the torch and just use a bit of wire to test the button function only? Just like in post #18 but try welding with it and see if it releases straight away when slopes are 0?