Need a few tig tips

[Jorville]

I am still trying to get an acceptable weld on 3/16 mild steel. I can make the top side look really good. the bottom is not an acceptable 100%. there is a little suck back. This is an open root weld. Roughly 37 degree bevel. I have gaped it 1/8 and 3/32 used 3/32 filler and 1/8 filler. The 3/32 filler seems to work the best, wit a 1/8 gap but still not an acceptable 100% weld. I have yet to see a key hole some may call a fish eye. anyone have an idea as to what I am doing wrong.

 

[Shield Arc]

Do you use the lay wire technique, or dip the filler rod?
I like 37 1/2 degree bevels. 3/32-inch gap, and use 1/8-inch filler rod. I run around 90 to 95 amps. For the hot pass I only go up 10-amps, and switch to 3/32-inch filler this helps prevent suck back.

 

[Jorville]

Shield Arc
I dip the rod, I tried the lay wire and did not have a lot of luck with that. The bevel is hand ground so it is close to 37 degrees, not perfect. I tried to match what the butt weld pipe fittings look like, land and all. I am using that old Miller Dial arc so the amperage is a guess. I though I should be able to see a key hole.The range selector is set 40 to 190 and the dial is at 80%, I am not sure where my foot is at, just try and keep a puddle.

 

[Shield Arc]

I don't use a land at all for Tig welding open root. I do for SMAW. When dipping the filler rod wait until you see the key hole before dipping the filler rod.

 

[Shield Arc]

Couple thoughts:
How are you sharpening your tungsten? For open root welding I like a real long taper.
Are you walking the cup? If so I bevel the cup a little bit.

 

[Jorville]

shield arc
The tungsten is sharpened fairly long maybe not as long as the one you show. I will try a little longer. The distance between the two pipes is pretty narrow so I was trying to just go straight with no side to side movement. The pipe is eight joints of 2 1/2 inches and four will be 1 1/2 inches. The 1 1/2 pipe has a wall thickness of .130, a tad over 1/8 inch. I haven't tried the thin weld yet. I have yet to see a key hole, that is why I went to a 1/8 gap. And I still do not see a key hole. I am doing something wrong somewhere.

 

[Shield Arc]

I still do not see a key hole. I am doing something wrong somewhere.

Just set there with the power on, the key hole will appear. A lot of it has to do with torch angle. You'll have to play with that to see what angle works best for you.

 

[Mark @ Everlast]

I would not put a big key hole in it. You really don't see the key hole until it just appears. It's not as big as you think. It just starts to open up and bam! you add wire.

 

[Jorville]

Just set there with the power on, the key hole will appear. A lot of it has to do with torch angle. You'll have to play with that to see what angle works best for you.

I went down to 3/16 material and turned the machine down to 65% of the 40 to 190 range The first coupon is 3/32 gap, and 3/32 filler rod. I never really saw a key hole, just fuzzed the two pieces together moving the torch back and forth a little, and added a little filler. Second picture is the under side it has a lot of suck back and is very wide. Why is the under side so wide. The third picture the pieces are at a 1/8 inch gap There I saw a small keyhole and added more filler the key hole disappeared though and I continued to add filler. The underside is still wide and still has a little suck. Why are the undersides so wide. I though I would get a 1/8 or so bead on the underside. You can see I stopped midway just to see what the underside looked like.

 

[Shield Arc]

Why are the undersides so wide.

Because you are cooking the plate. Too much heat, or too slow of travel speed.
Try a 37-degree bevel. 3/32-inch gap, and use 1/8-inch filler rod. Along with the lay wire technique. Push real hard on the filler rod. Like you are trying to push it through the plate. Also make sure the puddle is just a hair bigger than the width of the 1/8-inch filler rod.
I think you will a lot better results just starting out with open root welding.