Help - poor penetration using thin metal technique.

[schnappi]

Hiya,

Been trying the "thin metal technique" on approx. 1mm steel (butt welding) and overall it seems to work really well. Only thing I've noticed is that the weld penetration seems to be poor? If I go move more slowly I tend to blow through so I figured I'd step up the power and increase the wire feed instead. I'm now at a stage where if I try and run a short seam (a letter N shape) I end up blowing through, however I'm still getting poor penetration using the thin metal technique.

I'd say I'm overlapping the previous weld by about 1/3 and am hitting it whilst it's still glowing. Torch is about 20 degrees from vertical pointed back towards the previous weld.

Anyone have any tips on getting better penetration using the thin metal technique? Am I waiting too long between pulses so the previous weld is cooling too much? (I'm probably waiting around 2 seconds between pulses).

Any tips welcome!

 

[Country Joe]

Maybe try out "Pushing" as opposed to "pulling" the torch or slightly longer pulses.
Maybe a shorter gap between pulses, too.
Thin stuff can be tricky, anyway!
All the Best
CJ

 

[redwine300]

Hi schnappi, I do not know much about your sip handymig, but hopefully it can go as low as 25/30 amps? Much higher and i think you will struggle on 1mm or less. Also, are you using 0,6mm wire?
All i can add is i would suggest staying at the lower end of the power settings for the time being. I have found that if i set the wire speed to as low as i can get away with and dwell just a little, everything happens at a more controllable rate allowing me to gain good penetration, most of the time.
I hope this helps, maybe a couple of pictures might help the more experienced members to advise. (welcome to the forum by the way)

 

[schnappi]

Hi schnappi, I do not know much about your sip handymig, but hopefully it can go as low as 25/30 amps?

Yep, 25 amps at the low end.

Much higher and i think you will struggle on 1mm or less. Also, are you using 0,6mm wire?

Using 0.8 flux cored wire (don't laugh, it does work even using pulsed welding as long as you don't let the previous weld cool)

All i can add is i would suggest staying at the lower end of the power settings for the time being. I have found that if i set the wire speed to as low as i can get away with and dwell just a little, everything happens at a more controllable rate allowing me to gain good penetration, most of the time.

I'll try going back to the lower settings and go really slowly.

I hope this helps, maybe a couple of pictures might help the more experienced members to advise. (welcome to the forum by the way)

Cheers.

 

[schnappi]

Maybe try out "Pushing" as opposed to "pulling" the torch or slightly longer pulses.
Maybe a shorter gap between pulses, too.
Thin stuff can be tricky, anyway!
All the Best
CJ

I'll try leaving a little less time between pulses, see if that helps. I guess if it's hotter (less time between pulses) it'll penetrate better.

 

[Country Joe]

I'll try leaving a little less time between pulses, see if that helps. I guess if it's hotter (less time between pulses) it'll penetrate better.

Gasless/flux cored wire usually burns hotter than gas shielded, anyway. I don't think gasless wire comes in 0.6mm either.

You've got a few things to deal with, SIP's can be quite awkward, gasless wire is quite fierce, you're stuck with 0.8mm wire, and welding 1mm sheet!
Those are what I'd call "constants".

Play around with the "variables", the things you can change. EG, wire speed, power setting, arc length (keep it short), travel speed, etc

Experiment away wildly, somehow, some setting you eventually find, will work.

All the Best,
CJ

 

[schnappi]

Gasless/flux cored wire usually burns hotter than gas shielded, anyway. I don't think gasless wire comes in 0.6mm either.

You've got a few things to deal with, SIP's can be quite awkward, gasless wire is quite fierce, you're stuck with 0.8mm wire, and welding 1mm sheet!
Those are what I'd call "constants".

Play around with the "variables", the things you can change. EG, wire speed, power setting, arc length (keep it short), travel speed, etc

Experiment away wildly, somehow, some setting you eventually find, will work.

All the Best,
CJ

LOL! Yep, I know I'm up against it with a SIP, gasless and 0.8 doing car bodywork.

Surprisingly I can actually get a reasonable looking butt weld which resists bending etc. so the MOT man would definitely be happy. Thing is, passing an MOT and doing a job I'm satisfied with are not the same thing.

In the past I've always lap welded but since finding this site I've been inspired to do a better job as seeing what some of you guys can achieve has raised the bar somewhat!

Ideally I'd like to grind the weld down close to flush to get a more attractive finish but without sufficient weld penetration I'm not happy doing that so I need to work on producing a more penetrative weld first.

 

[Country Joe]

Thing is, passing an MOT and doing a job I'm satisfied with are not the same thing.

I know what you mean!

Maybe it's possible to run a continuous bead along the pulsed line of weld, to give it a more uniform appearance, as the part where the pulsed bead is should be a bit thicker?

All the Best,
CJ

 

[keith19]

Schnappi, just in case it might be relevant, what make of flux cored wire are you using?

Some makes are much more tolerant of thin steel than others. If it's SIP or something similar or worse, or even Clarke, this puts up the odds against you quite a bit on thin stuff, as quality can be variable, to say the least.

 

[schnappi]

Schnappi, just in case it might be relevant, what make of flux cored wire are you using?

Some makes are much more tolerant of thin steel than others. If it's SIP or something similar or worse, or even Clarke, this puts up the odds against you quite a bit on thin stuff, as quality can be variable, to say the least.

You guessed it, it's SIP wire. Which flux cored wire do you recommend? (I'm almost at the end of the current spool)

 

[malcolm]

LOL! Yep, I know I'm up against it with a SIP

The wire takes time to get up to speed on those (takes about a second) which makes them terrible for cold starts. For the thin metal technique you'll be working in the range before the wire gets up to speed so turn the wire speed up much higher than you would use for normal welding for half a chance.

Probably a better approach for those on thin metal will be to weld in short runs at normal settings.

 

[keith19]

Hi Schnappi,

Lincoln Innershield NR211MP at 0.7 mm is well spoken of on here, and probably the best that money can buy in the UK. RapidWeld do it on the link below, also in larger reels.

http://www.rapidwelding.com/dynamic/DisplayItem.aspx?c=ED031448

Sifbronze is also reckoned to be excellent, available in the Weldequipe shop on-site, but only goes down to 0.8 mm.

I don't know if technical manufacturing difficulties prevent them making 0.6 mm in gasless, but the Lincoln 0.7 mm seems to be as small as it gets.

 

[schnappi]

The wire takes time to get up to speed on those (takes about a second) which makes them terrible for cold starts. For the thin metal technique you'll be working in the range before the wire gets up to speed so turn the wire speed up much higher than you would use for normal welding for half a chance.

Probably a better approach for those on thin metal will be to weld in short runs at normal settings.

Thanks for the tips Malcolm, I'll give them a try.

Hi Schnappi,

Lincoln Innershield NR211MP at 0.7 mm is well spoken of on here, and probably the best that money can buy in the UK. RapidWeld do it on the link below, also in larger reels.

http://www.rapidwelding.com/dynamic/DisplayItem.aspx?c=ED031448

Sifbronze is also reckoned to be excellent, available in the Weldequipe shop on-site, but only goes down to 0.8 mm.

I don't know if technical manufacturing difficulties prevent them making 0.6 mm in gasless, but the Lincoln 0.7 mm seems to be as small as it gets.

Cheers for the links to the decent welding wire.

 

[schnappi]

Probably a better approach for those on thin metal will be to weld in short runs at normal settings.

Tried this approach and it's much better (thank you!) and I'm getting decent weld penetration now.

Playing about with it for a while, the best method I've found seems to be a "move forward 2 steps then weld back 1 step" technique. Using this method of moving forward then welding backwards towards the previous stitch, I'm avoiding blowing through as it takes a while for the heat to build and when it does I'm nearly back on the previous stitch which then takes a little of the heat out before melting in nicely to give a nice continuous seam with good penetration.

I'm totally happy that the results are good and strong now so thanks again for steering me in a direction which is more suitable for my setup!

 

[Chickenjohn]

LOL! Yep, I know I'm up against it with a SIP, gasless and 0.8 doing car bodywork.
-snip-.

Once I read this, the only advice I can give is get a gas cylinder and normal mig wire if your welder is dual gas/ no gas. The thin metal technique will then work very well.