Tig 18ga steel - My best so far - Need help

[usersony]

I've been practicing using TIG to weld 18ga steel with the intent to go to thinner gauge up to 22ga.
I have learned how to tack the to pieces together and get good fusion welds on a butt joint, but I cannot get a bead going with filler on a T-joint. Sometimes I'll get blow-through, sometimes I'll get both side to puddle perfectly but not consistently.
Is MIG more suitable for thinner metals? I see most videos on body panels and thin metals are done with MIG.
Is this something better done with pulse?
Any help would be appreciated!

Here are some pics of my best tack/fusion welds.
18ga steel
1/16 E3 electrode
140 amps
100% argon

[Oscar]

the main question is why are you doing 140A "blasts"? How are you controlling the current? Foot pedal? and why are you attempting to weld it to a thick piece of steel?

[usersony]

An instant blast of 140 amps allows me to fusion tack both plates together with out blow-through. I am using a foot pedal. I am not trying to weld it to a thick piece of steel. In one of the pictures it looks like the vertical piece is thicker but its just not a clean cut from my cut off saw. Both pieces are 18ga steel.

[geezerbill]

Are you not using filler material?
It appears as though you are not.
On thicker material, one can keep a puddle going just using the parent metal, with no filler.
On 18 gauge, it is less likely that you will be successful doing this on a fillet weld. After all, the metal that becomes the puddle, has to come from somewhere, and most likely, it will come from the vertical piece, gravity being what it is, and if gravity causes the metal fro the top piece to flow down to the bottom piece, there is a good chance you will get a hole where the metal used to be
With filler wire, you can get the puddle started on the top piece, add a little wire to the puddle at the top, and let gravity pull it down as you move the arc from the top piece to the bottom.
Then it can just be a matter of adding to the puddle with your wire, as you move the puddle along, dab, dab, dab.
You may still have to try to add the wire to the top part of the puddle, and wash it down with the arc, but being careful to keep the heat low, and not climb too high on the vertical piece, thereby avoiding undercut. Just a tiny bit of undercut on thin material means you will have removed most of the parent metal.

[usersony]

With filler wire, you can get the puddle started on the top piece, add a little wire to the puddle at the top, and let gravity pull it down as you move the arc from the top piece to the bottom.

Nice tip! Will give it a try!
Would aluminum blocks as heat sinks work to reduce the blow-through?

[geezerbill]

Nice tip! Will give it a try!
Would aluminum blocks as heat sinks work to reduce the blow-through?

You won't need that once you get the hang of it.
Start by turning your machine down to where is colder than it needs to be.
This will give you a chance to see how the metal reacts, and also give you a chance to react to how it reacts
The way to control blowing through, is by turning your machine, or by moving more quickly, using proper technique.
In the beginning, turning the heat down is way easier than moving quickly with good technique.

Oh yeah.
By wire, I mean .045 solid mig wire, or maybe .035 wire.

At your stage, getting the puddle hot enough to melt 1/16th TIG wire may cause you to blow thru.
You can run pretty cold, and still keep the puddle going using 6 or 8 inch snips of MIG wire.

[usersony]

Update: geezerbill, I use some Mig wire like you suggested, had 0.025 here and does the job extremely nice. I ended up buying some 0.045 rods since it was about $10 cheaper than 0.035 rod.
Here is a picture of my progress with filler rod:
Foot Control
18ga steel
9F torch
1/16th E3 tungsten
#7 Cup with gas lens
12 CFH of Argon

[Burpee]

I'ma likin' that Sonny. Go do 100 feet.

[geezerbill]

There ya go.
It is already starting to look pretty consistent.
You will learn how much wire you can add, how little you can afford to add, how much you must add, how fast you can travel, how fast you must travel...
well, you get the idea.
The only way to learn how fast is too fast, is to go too fast, and recognize the effect. the only way to learn how hot you can afford to run, is by running too hot, and recognizing the effect, etc.

Experiment going too cold, too hot, too slow, too fast, too much filler, too little filler, and pretty soon, you will recognize when you get outside the acceptable parameters without even having to think about it.
To me, that is when welding got fun, because my brain, eyes, hands all could weld all day, and my mind could be on a beach somewhere in the Caribbean