[shoebox1956]

Hello,
I have a small HF inverter TIG/Stick welder (I have welded with the stick feature). It started life as a scratch start but, the unit has high frequency. I added a cheap foot pedal successfully and first attempt I had 2 wires backwards so down was off and up was full current. Changed that around and proceeded to test by welding 2 small scrap pieces together approx .090 thick, maybe a little less. I completed one tack and on the second attempt, the flame went out and the torch started glowing, the electrode was cherry red. I do not remember if I immediately took my foot off the pedal or not, been a while. I unplugged the welder. My large Argon bottle was hooked up, turned on and the solenoid works correctly. The weld I did make is probably the best tack weld I ever did. Since my experience with TIG is very limited, does anyone have any idea as to what might have happened? The welder itself is not burned up, from what I can tell. I am thinking that the foot pedal is not the reason or the internal breaker would have tripped or things would have melted inside. I did make one weld. Could a loss of ground or a really poor ground cause this?

[AFSATCOM]

The electrode will glow. This is normal. If the electrode were to melt away or the heat in the torch head caused plastic to melt, you got problems.

Am I not understanding the question?

[AKweldshop]

Yeah.
Your tungsten electrode will get "cherry red".
What amperage were you using, and what size tungsten???

~John

[shoebox1956]

This was not a normal condition. As I tried to put a second tack weld on, the flame went out and then the electrode started to glow. The electrode was not stuck to the work piece. It appeared to get hotter so I switched the welder off. It couldn''t have taken much more than five seconds total and it scared the daylights out of me. It was HOT. That is why I was asking about the ground. I went out in the garage after posting to check the torch (haven't touched it since this occurrence back in September) and I replaced the collet and collet body and washer just after the incident. I broke off about 2 inches from the electrode. I reacted quick. It should not have done this for the amount of time I had the pedal down. I guess I will just have to gather a little courage and give it a retry, see what happens. I do not know if I had electrode + or electrode -. The connector will fit in either hole but I did not rearrange the ground connection, it is still as it came from HF. It has a 9 sized torch, I was using a 1-16th thoriated electrode (red stripe) and Argon gas. The first tack went beautifully.

[Otto Nobedder]

It's possible you had it electrode positive, which would concentrate the heat in the torch.

You should have the torch and ground connected opposite of what works for stick.

Steve S

[shoebox1956]

Afsatcom,
I have a feeling that in my haste, I did something wrong such as hook the torch to the leads backwards. I will be repairing my snowblower before too long - I need to repair the skids which are worn out and that will require welding. I will try the HF unit again and see what happens, making sure the leads are connected with the electrode negative and the ground positive and go over the wiring schematic and instructions beforehand. If it works, I will post. If not, maybe I can still use it for small stick welding jobs. I am a member of EAA Chapter 143 in Middle River, MD at the old Martin aircraft facility and we are constructing an Aeronca TG5 training glider from the fuselage of an O-58 Defender. This compact unit would be excellent to do tack welds during reconstruction.