new to welding - welds collapse in frothy heap!

Gas mark 5 · Nov 4, 2007

Hi I'm new to mig welding and I have recently brought a new mig welder (30-145amps telwin gas/gasless) but when I try laying practice welds on a piece of 2mm sheet they usually go really bubbly and frothy at the end and dont seem to be at all smooth. when i just weld in a straight line it comes out very smooth and neat but as soon as I weld in any form of zigzag it does what I have described above. am I using the wrong settings or using the wrong style? can someone please shed some light on this
P.S. I have my welder set to setting 3 for amps (out of 4) with a wire speed of 4(out of 10)
:flame:

malcolm · Nov 4, 2007

What sort of shielding are you using? With gasless wire the flux can look frothy and collapse like you describe, but the welds underneath the flux are OK. If you are using normal wire with shielding gas then there's a problem with your gas supply.

Ooh - and welcome to the forum. :hug:

Gas mark 5 · Nov 5, 2007

I am using normal wire with a small disposable gas bottle. I did have problems with the first regulator I brought, it would take about 5 whole turns to stop it spraying me with CO2, but I have got a new one now and it seems fine, gas stops hissing after half a turn when screwing it on, when you open it you can hear a healthy hiss and you can hear the gas coming out of the nozzel.
I am using CO2, which I know is not as good as argon/CO2 but I thought it would be fine for practicing
Bit stuck, any ideas?

P.S. I am welding outside due to lack of space inside, but there is practicly no wind and it is in a very sheltered location
:welder:

matt1978 · Nov 5, 2007

[QUOTE

P.S. I am welding outside due to lack of space inside, but there is practicly no wind and it is in a very sheltered location
:welder:

[/QUOTE]

I think that there must be some wind blowing away your shielding gas.

From how you describe it "Frothy" I think that you mean Porosity (Small gas holes in the weld) this can be caused from........

lack of sheilding gas
Contamination on the wire or on the plate (Rust, Oil, Water etc)

If its only happening when you are weaving then maybe you are weaving very fast and not allowing the gas to cover the weld bead sufficiently.

I am 99% sure that its because your welding outside tho. Try welding indoors, even if its only just a few cm of weld, then atleast you can eliminate 1 factor.

Wozzaaah · Nov 5, 2007

Can you post some close up pics of your welds? It would help us to understand what's wrong.

Gas mark 5 · Nov 6, 2007

I'll post some pics soon, my cameras charging up.

Hitch · Nov 6, 2007

Sounds like perhaps you are stretching for the last bit of the weld. In other words, you might be moving your torch away from the metal as you move along the joint. Easily done, especially if you new to it.

Where abouts in Somerset are you btw?

Gas mark 5 · Nov 6, 2007

Pics of my rubbish welds!

Hi here are the pics, (hopefuly!)

P.S. I live in batcombe, near Shepton Mallet

Welderpaul · Nov 6, 2007

Apart from the weld on the middle picture which looks ok (I've seen professional welders produce worse welds!), i would say either contaminants (rust/oil) on the plate, or a lack of shielding gas. Given that it looks like you have run the grinder over the steel before welding, my money is on not enough gas flow (The brown staining all over the welds is a sure sign of not enough gas) either the reg is playing up, or wants opening up more to give you a better flow of gas. As Matt says, that's deffo porosity in the welds.

Hitch · Nov 6, 2007

Its not what i suggested earlier. Looking at the pics, i think your either holding your torch a litle bit far away or could do with a bit more gas flow.

Gasman · Nov 6, 2007

Welcome t' forum,

Yes, I would agree you have a gas issue with some of your beads having porosity, is the shroud fitted firmly and can you still hear gas. Its likely that after only that amount of practice your disposable bottle will be empty.

Gas mark 5 · Nov 7, 2007

I am sure that I am holding the torch at the right distance, and I ran over both sides of the metal with an angle grinder so I think that it must be the gas, but surely the gas flow is either on of off, there isn't any in-between is there? I am using a tiny regulator that fits on disposable gas and I didn't think that the amount that came out was ajustable. Then again, what do I know?!

Gas mark 5 · Nov 7, 2007

Oh, do the gas bottels really run out that quickly, I had done a bit of practicing before that as well... But I feels quite heavy and I can still hear a lot of gas coming out, how do you tell if the bottel is empty?

malcolm · Nov 7, 2007

Gas bottle won't be empty when there's still gas coming out, but you would only be looking at 6 minutes continuous welding at a good flow rate.

The flow rate is adjustable even on the little regs by turning the black knob on the top. Though for some reason the regs you buy these days don't adjust too well. You'll need to screw the adjuster down almost all the way.

Set it by holding the trigger in the torch with the welder switched on. There will be an initial rush of gas, but screw the reg down until you can hear the constant flow well. From there you can mess around with the adjustment so the welds look good but you don't use too much gas.

Gas mark 5 · Nov 8, 2007

Thank you, I have some more practice...

Gas mark 5 · Jan 13, 2008

Just thought that i would point out-i am still using that same gas bottle a couple of months later, it barely feels half emptly and I have covered two more plates of the same size with welds. Not sure that the gas is working.
Sorry I deserted this post, but there was so much on and since I have barely any metal, I couldn't do any practice for ages.

Gas mark 5 · Mar 20, 2011

Yuck!

I was just reading up on This thread about shielding gas and found a link to my own thread, which I had clean forgotten about. :ashamed:

So, to help anyone else out with this problem, disposables are utterly useless. :mad:

I now have a pub C02 bottle for most occasions, which is infinitely better. OK, it's not the best, but I can actually weld now, not like those horrid brown lumpy things before.

I'm looking into a bottle of argon-shield as well, because I'm working on 2cv's mostly now, which are not renowned for the thickness of their metal.

But yes, I never want to touch a disposable again.

Thank you everyone! :hug:

new to welding - welds collapse in frothy heap!

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