Weld Porosity

[inthefrey]

Greetings all!

I started welding up the new cart this week and found I'm having problems with weld porosity.
The material is 1/8" wall by 1" square mild steel tubing. All basic butt joints - nothing fancy.

Using 3/32, 2% Lanth. electrodes.
Filler - 3/32 ER70S-2
Amps set between 80 and 90.
Material is cleaned with flap disk.
Pre and post flow set to 5 and 8 respectively. I'll start the weld, puddle forms, add filler and start moving. About 7-8 second in, I SEE THE PUDDLE START TO BOIL BEHIND ME!

Tried reducing amps
increasing flow rate - reducing rate. slowing down, speeding up
went to larger cup size.

Arrrg!!!!

Used almost a whole 60CF bottle of gas this afternoon trying to figure this
out and,............


Wait for it....


I'm absolutely sure I doing something stupid.


Recommendations welcome. THANKS!

[sportbike]

How much argon flow do you have?

The puddle should be frozen pretty much as soon as you move.

[Brian Ski]

Just a newbie here... So take my advice with a grain of salt... Was told to use tungsten rod about 1/2 the thickness of the material. Try a 1/16" rod and see if it concentrates the heat better.

Sounds like air getting to the weld before it has completely cooled. So maybe to hot and moving faster. The smaller rod may help.

Will have to keep watching and see what the pros say.

[CGCINC]

I've had this happen one time and that one time I was Extremely hot just trying out the new welder settings.

Maybe try a larger cup size to get better gas coverage.

[inthefrey]

How much argon flow do you have?

The puddle should be frozen pretty much as soon as you move.

Using approximately 15CFH - acording to the gauge that came with the PP 205, about 7.5 (CFH x 0.472). Too much? Not enough?

[Buggy Chief]

Using approximately 15CFH - acording to the gauge that came with the PP 205, about 7.5 (CFH x 0.472). Too much? Not enough?

I have the PP205 too and sounds reasonable, especially with your pre and post flow settings. I agree with CGINC, try a larger cup with a gas saver lens. In my opinion it concentrates the argon in a more consistent manner. Once I did this, I was able to dial the argon flow back to 5 lpm and used pre and post flow accordingly.

[inthefrey]

Well, I may have figured it out.

I believe I have found my smoking gun.....Guess what kind of hose I replaced my old hose with because I thought I was getting a good deal?! They were only $9.99 for a 25' length!

http://forum.weldingtipsandtricks.co...php?f=5&t=1022

Fixed the link. I dunno?!


I guess I'll be at HD tomorrow - spending some money on new tank lines. Going to give it a try and see what happens.

[DaveO]

I get an error when I click that link... what happened? The hose failed on you?

[Brian Ski]

I get an error when I click that link... what happened? The hose failed on you?

I found the thread...

http://forum.weldingtipsandtricks.co...php?f=5&t=1022

Crappy hose...

Interesting. The link gets altered... Try this if the above link does not work. Might have to cut and paste it.

//forum.weldingtipsandtricks.com/viewtopic.php?f=5&t=1022

[inthefrey]

I found the thread...

http://forum.weldingtipsandtricks.co...php?f=5&t=1022

Crappy hose...

Interesting. The link gets altered... Try this if the above link does not work. Might have to cut and paste it.

//forum.weldingtipsandtricks.com/viewtopic.php?f=5&t=1022

So, according to the info above, the cheap lines are bleeding chems, gases or whatever into the argon. I'll be replacing the lines tonight. I'll let everyone know if it helped or cured the problem.

[zoama]

So, according to the info above, the cheap lines are bleeding chems, gases or whatever into the argon. I'll be replacing the lines tonight. I'll let everyone know if it helped or cured the problem.

Are your hoses polyethelyne (thin simi-rigid) or PVC (similar to rubber air hose) ? I use PVC air hose with no problems. The clear braided hose that comes with the welders is also PVC.

[inthefrey]

Are your hoses polyethelyne (thin simi-rigid) or PVC (similar to rubber air hose) ? I use PVC air hose with no problems. The clear braided hose that comes with the welders is also PVC.

Hi Zoama. They are PVC. However, they have got to be the stiffest hoses I've ever used. If it's cold, forget about it! Like I said, I got them on the cheap so, no great loss in giving this a try. Actualy, the one I'm replacing looks like the blue one! In any case, I'll have an extra now.

Now, all this may be an excersize in folly and I just got a bad tank of gas. I get the tank filled tomorrow - from a different dealer.

I'll get it figured out.

Thanks!

[JBnID]

Tubing is sometimes tough because the heated air inside will blow out through the puddle.
Argon is heavier than air--when welding up tubing, try to have the open end of the tube up. Before welding the joint, trip the torch with the post flow set on 20 seconds or so and fill the tube with argon, then weld. If the tubing has to be open end down, always stuff a paper towel in the bottom to kill the 'chimney' effect that blows air on the back side of the puddle.

[inthefrey]

Tubing is sometimes tough because the heated air inside will blow out through the puddle.
Argon is heavier than air--when welding up tubing, try to have the open end of the tube up. Before welding the joint, trip the torch with the post flow set on 20 seconds or so and fill the tube with argon, then weld. If the tubing has to be open end down, always stuff a paper towel in the bottom to kill the 'chimney' effect that blows air on the back side of the puddle.

This is a GREAT tip! Never though of this but it makes complete sense. THANKS!

[zoama]

Heated air only blows through the puddle on tubing when you make the last weld to seal it. Always back purge stainless but on steel or aluminum you can leave a small opening on the last weld, then come back and close it when cooled without purging.