Welding Tips and Tricks

First of all, I want to apologise for lack of pictures, I'll have them within 24 hours, right now I'm hoping someone will figure it out with just a wall of text.

Now, I'm welding 2 pieces of pipe into a T-shape. They're laser cut to a tight fit to allow free flow inside and are supposed to be welded without filler rod. Inside doesn't matter so that thing's without purge. I have no problems going through the inside corner but when it moves to a butt joint on the side it's starting to get messy. The arc starts to jump from one pipe to the other causing an ugly snakelike weld to appear. I think (cause I can't see and am not experienced enough to stop mid way to see) I've already tried all the possible torch angles with a 50/50 chance for that ugly crap to appear. I filed the edges off and degreased the material. Helped with some porosity but not the arc itself.
What might be the cause?
Torch angle? Welding speed?
I couldn't find any good videos showing how to weld a butt joint without filler rod.
I tried 60 amps going fast as well as going slow with 35 amps, the arc still wandered off to the side regardless of the amperage.

What's the general technique for welding such a joint?


Oh, I almost forgot.
The material is 3 mm heat resistant steel (not sure which one though) and I have access to pure argon and an argon hydrogen mix. The pieces are for a pellet heater.

(I'm from Poland so I might not have used the proper terminology, I apologise)

Hard to say what the problem is without pictures.

Hello Jarosh and welcome to the forum
Let us know what size pipe and wall thickness, not sure why you'd want to weld something like this without filler.

It sounds like you have a saddle joint that's been laser cut, so I presume the fitup is good without any gap.

The material must be clean of any foreign contaminates, don't forget the inside of the pipe at least 40mm back from the weld joint

We will need more information.
Material designation.
Material diameter and thickness.
Type of electrode.

If the steel is a low carbon steel an autogenous weld won't be reliable you must use filler.
Your tungsten should not be pure and should be sharpened to a point.
If your tungsten is sharp arc wander happens with low amps - increase it. Can't recommend correct amps without answers to above questions.