Porosity question

[Dan]

Originally posted by e-z-ride.com
Thanks for the info.

on the topic of listening for the sound, I've sorta trained myself to listen for that bacon sizzle sound. And I've gotten pretty used to hearing this sound fairly consistently with using that flux-cored gas-less 0.030 wire.

Now that I've changed over to the 75/25 argon gas, what I hear when I weld is a much louder welding sound. The sound isn't like that bacon sizzle I'm accustomed to...it's more like the sound of 10.000 steel ball bearings raining down violently onto very thin sheetmetal.

I don't think much of it because I just figured that this is normal for gas shield MIG welding. But now I just have to ask...is this normal?

And finally, at the end of my weld bead ( a 3/8 x 1" bead), at times I see a small formation of a large water droplet collecting. If I leave it overnight on the weld, the next morning, a trace of surface rust will coat over that area. Not sure if this is normal for gas shield MIG or not...so please let me know what you think.

Many thanks.

If your seeing moisture at the end of your weld and having a problem with porosity I would begin to suspect that the CO 2 in your shielding gas is low quality. As Roger stated take the bottle back an exchange it for a new one. This year I have received to bad bottles of argon both bottles made my TIG welds on stainless steel turn out black. I just took them back to the supplier told them what was going on , and they gave me a new bottle. Plus they gave me a card for a free refill.

[e-z-ride.com]

Originally posted by Will
One other thought...did you switch the polarity of the torch when you went from flux core to gas?

Yes, I did change this out.

Rocky D:
Your suggestion to listen for the gas flow before striking an arc is well received. I didn't know that...thanks for the tip.

I'm sticking out the wire...sometimes 1/2" - 3/4" from the tip
Usually, when I have to cut off some of the wire, I try to snip it @ 3/8". But I get the picture...I need to pay more attention to this in order to get better gas shielding.

[Will]

One other thought...did you switch the polarity of the torch when you went from flux core to gas?

Originally posted by Rocky D
Sounds like what you have is a gas problem, either too much, or not enough...both will give you porosity. Also, torch angle may be a factor, too....keep it pointed so that the gas will cover the puddle. Don't let your torch angle get too steep. I have trained myself to listen to the gas and not rely on gauge settings....gauges are seldom right or consistant.

I'm sorry, I didn't make myself clear as to listening to the sound...what I listen for is the sound of the gas passing through the nozzle, before I strike an arc.

Hold the nozzle up to your ear, and listen to the gas coming out, when you have it right, and memorize that sound. I do it with TIG also.

As to what you are listening to, makes me ask What is your stickout? Could be excessive, (too far away).

Sometimes bad shielding gas will turn up. If changing flow rates doesn't help take your near full gas bottle back and exchange it. Should be no charge.

[e-z-ride.com]

Thanks for the info.

on the topic of listening for the sound, I've sorta trained myself to listen for that bacon sizzle sound. And I've gotten pretty used to hearing this sound fairly consistently with using that flux-cored gas-less 0.030 wire.

Now that I've changed over to the 75/25 argon gas, what I hear when I weld is a much louder welding sound. The sound isn't like that bacon sizzle I'm accustomed to...it's more like the sound of 10.000 steel ball bearings raining down violently onto very thin sheetmetal.

I don't think much of it because I just figured that this is normal for gas shield MIG welding. But now I just have to ask...is this normal?

And finally, at the end of my weld bead ( a 3/8 x 1" bead), at times I see a small formation of a large water droplet collecting. If I leave it overnight on the weld, the next morning, a trace of surface rust will coat over that area. Not sure if this is normal for gas shield MIG or not...so please let me know what you think.

Many thanks.

Sounds like what you have is a gas problem, either too much, or not enough...both will give you porosity. Also, torch angle may be a factor, too....keep it pointed so that the gas will cover the puddle. Don't let your torch angle get too steep. I have trained myself to listen to the gas and not rely on gauge settings....gauges are seldom right or consistant.

[e-z-ride.com]

Thanks very much for the quick responses.

Here's a follow up to questions above:

1) I'm welding in a covered utility workspace...about the size of two-three parked cars inside of a garage. I have three walls shielding the outside and I keep the hangar doors raised open. I don't get much of a breeze within the shed. So it's safe to say that I'm getting hardly any drafts.

2) I am NOT removing any mill scale off the HRS prior to welding. The cold roll 5/8 bar is degreased and is very shiny and clean.

I will try a few of the pointers posted here and see if things will improve. THanks again.

Is your argon flow rate set at 22 pounds or 22CFH? 22CFH should be enough but if there is any wind it needs to be shielded from weld area and a little higher flow rate might help. I have used a weight in paper bag next to weld to shield wind to big wind/welding screen sold for that use. Sound of arc changes and more volts are needed to sustain arc when welding without or with poor shielding.

As said by others metal for MIG weld needs to be cleaner and dry compaired to flux core weld.

[Dan]

Are you welding outside, where a breeze might blow your shielding gas away? You might need to check out all your connections and make sure you don t have a leak some where, that isn t allowing the complete flow of gas to reach the weld. Just a couple ideas incase your base metal is clean.

Also, are you removing the mill scale from the 3/8" flat bar?

[Will]

Sounds like the metal may not be clean enough? Get any paint/rust out of the way and the porosity problem should go away too.
I agree on your comment with 75/25...it sure makes a nice clean weld, no splatter AND no chipping slag!

[e-z-ride.com]

With my HH175 , 25/75 argon & 0.035 solid wire, I was welding 5/8" dia round cold roll T1018 onto 3/8" x 1" hot roll and I noticed that I would get porosity into the welds.

I had the argon pressure set at 22lbs, voltage setting @ #4, wire feed @ 55.

I've never used gas & solid wire before. I've used shielded Hobart 0.035 wire in the past, and didn't notice that much of a porosity problem with it.

Man, I do love the way the welds look when using gas & solid wire, though...