Newbie issues with wire and welds

[Chapster]

Hi everyone,

I spent some weeks perusing this website, the guides, and this forum before buying an SWP 150 Turbo mig machine and have now put some time in practising and practising, which has led to some questions!

Using 1.2mm mild steel plate for practising the whole time.

Started laying beads using 0.8mm wire and CO2. I discovered how tricky it is getting voltage and wire speed set right enough to get what looks like a half-decent weld. Found that I was either getting only spots of approaching penetration on the underside, or was melting holes through. If I didn't move the torch fast enough, holes. I was surprised to find that of the 4 voltage settings I have, I had to use the 3rd highest. Minimum just created slugs that sat on the metal. Second highest just slightly better but not blended into parent metal, 3rd seemed good. Even so, had to put up wire speed to get good penetration but then found it hard not to burn through sometimes.

Then I tried with some 0.6mm wire. Again I have to use the 3rd highest voltage setting, and found I could only get good penetration without slowing down torch speed to the point of burning through by holding the torch so close to the metal that the shroud is touching the metal. Trying to use the recommended distance of 6mm to 10mm causes poor penetration.

Latest I've tried is 0.8mm flux core gasless wire. This has confused me, as I've had to go to minimum voltage setting and turn the wire speed right down in order to stop blowing holes. Even with the minimum voltage and really low wire speed, it's still putting so much heat into the metal that if anything it's penetrating too far and the surrounding metal glows red after I stop, whereas with solid core and CO2, mainly only the bead was red hot.

The beads are terribly ugly with flux core, but if only I could achieve that penetration so easily with solid core. Please advise! I'm a bit confused with my differing results.

Thanks.

 

[daleyd]

Get some thicker metal to practise on, once you've got the technique sorted on that only then move on to thin sheet. If you try on thin sheet first you'll just frustrate yourself. You can of course jump straight in if you have an urgent need to get a job done but it's not the best way to start.

You may also need to use the "thin sheet" method of welding in short bursts, depending on the thickness of the sheet and lowest welder settings.

Also, and I've never tried this so its only second hand info, I believe a bit of copper bar behind the weld can help on thin stuff.

 

[Kent]

sounds like you have something out of kilter there, not sure what or even if the plant is duff. Try this get some 3mm thick steel turn everything wire and power up full max it out I mean! Now work slowly backwards wire speed first a bit then when it welds right, start stepping back the power settings bit by bit each time followed each time by the wire. Also check your return clamp has good connection to the work at the cable ends and back at the plant, is your contact tip correctly sized to your wire? Are you connecting it up to a good direct supply or at the end of a flimsy extension lead?

The 3mm will hold out enough for you too see if you have some guts in the plant or if indeed you have an issue some place

 

[norlander]

+1 ^^^ fluxcore burns hotter than gas shielded,or at least it does with my kit. I "serviced" my return clamp this morning, cut and remade the cable attachment to the clamp and cleaned up the clamp.
Welding outside with fluxcore, first weld,I had to trim the settings back because of the improved return contact.
MIG is quite sensitive to bad return contact-I learnt that from welding tips and tricks and from experience, and to use a quote by one of the chaps on here re attaching the return-"clean as possible and close as possible"
So check the return is ok, and then try Kents suggestion.
BTW, penetration may not be uniform and don't get too hung up on it for the moment, try various settings and then break the welds to see how strong they are and compare the pen of each piece etc.
Good luck in getting sorted.