Welding Tips and Tricks

...sorry, couldn't resist that title

But actually it is this I am having problems with.

I'm new to mig welding but I've got two to three hours practise of running beads and I have now gone through and written down correct settings for various thicknesses to get my welder sizzling each time. I simply bought a bunch of plates from my local metal fabricators for ten pounds and have been practising and practising.

I am totally comfortable with laying beads and I always get a great 'heat leach' under the workpiece as I set up the mig for the hottest it can take without burning through and I'm actually surprised that steel down to 1.5mm is welded on the hottest setting for the welder. Im also using the 'loop to loop' technique to make them look pretty and most of all it's bloody good fun


Anyhow, I digress

So I tried my first few butt welds. I tried with root gaps of varying thicknesses and still I can't get the penetration correct. I have looked online and it's definitely the case that you shouldn't be able to still see the join on the backside of the workpiece. Well, even with whatever root gap I set it still won't come through lie that and I can see the gap.

Will bevelling in addition to a root gap really help? Were these other internet sources correct when they said the weld had to come through? I bashed a welded piece about a bit and in fairness the first thing to break was the middle of the steel and not my weld join.

What do you think?

Thanks in advance.

Steve

Yes, Steve (good lord, ANOTHER Steve...),

Bevelling will help. I've done MIG root on pipe, and it sucks! Yes, bevel it. I prefer a knife-edge and a close fit.

I haven't had to do this in years, and hope never to do it again.

Steve S

Will do mate, thank you!

Should I bevel it at a 45 degree angle? Cheers

At school we did 30-35, as that was near code.

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Thanks Jasper,

I didn't have any time to break out the welder today but I did get 5 mins to prep my workpieces.

Got some 1.5mm steel now with bevels at a tiny bit shallower angle than 45 degrees. going to leave a tiny gap. and use loads of stitch welds at different intervals allowing the piece to cool. and see if I can get this elusive penetration!

Welding Bear wrote:Im also using the 'loop to loop' technique to make them look pretty


So I tried my first few butt welds. I tried with root gaps of varying thicknesses and still I can't get the penetration correct. I have looked online and it's definitely the case that you shouldn't be able to still see the join on the backside of the workpiece. Well, even with whatever root gap I set it still won't come through lie that and I can see the gap.

Will bevelling in addition to a root gap really help?

Loopity-loop isn't going to be the best technique for maintaining a consistent melt thru(reinforcement) on the back of the joint. A straight stringer pass, watching the puddle(slight whipping forward ahead and back to the puddle can decrease penetration so becareful with that technique) and travelling along the joint as your eyes see and your hands adjust to what the puddle is needing at that moment in time.

Beveling will most definitely help with penetration at the root. Square groove butt joints(no bevel) are for thin materials(3/8" thick or less) and you adjust the root opening to achieve more or less penetration.

Thanks JWright,

Thing is I was not getting penetration on very thin 1.5mm steel (is 3/8'' about 10mm? lol).

I am on the absolute max setting for the welder and a bang on half way wire speed (5 out of 10).

Beads look awesome and im really comfortable laying them. but just no penetration other than the heat leech looking things.

I'm praying the bevels and gaps combined work. cos otherwise I don't know where to go with it

ps, point taken re the ''looping''..... ill just run straight beads

Hi guys,

So. Went out this morning.

1.5mm steel. 45 degree bevels on each piece. Gapped. Welder on max. settings with a mid range of wire speed.

Penetration much improved. But still not covering the join lines on the backside of the workpiece. i'll throw a few photos up in a few.

Wonders what I'm doing wrong.

Only other thing of note.... I re-tested my gas flow. I clearly misread the tester before cos I'm actually only getting 3LPM of CO2 gas. wondering if this is why I'm not getting enough pen.?

Welding Bear wrote:Hi guys,

So. Went out this morning.

1.5mm steel. 45 degree bevels on each piece. Gapped. Welder on max. settings with a mid range of wire speed.

Penetration much improved. But still not covering the join lines on the backside of the workpiece. i'll throw a few photos up in a few.

Wonders what I'm doing wrong.

Only other thing of note.... I re-tested my gas flow. I clearly misread the tester before cos I'm actually only getting 3LPM of CO2 gas. wondering if this is why I'm not getting enough pen.?

Even a lil 100amp welder should blow a hole through material that thin with a squeeze of the trigger. Curious how many volts/amps that thing is really producing.

W B,
Are you using 75/25 Argon/CO2 or 100% CO2 ? I'm no Mig expert but if I remember right 100% CO2 penetrates better than 75/25. There's plenty of others here who know way more about Mig than me and someone here can surely help you get to the cure.

Len

Braehill wrote:W B,
Are you using 75/25 Argon/CO2 or 100% CO2 ? I'm no Mig expert but if I remember right 100% CO2 penetrates better than 75/25. There's plenty of others here who know way more about Mig than me and someone here can surely help you get to the cure.

Len

Hi Len,
Not trying to be contrary...but in my experience the Argon mix generally runs a bit hotter than 100% CO2. If you take a look at the suggested welding parameters on the data sheets for (dual certified) gas shielded fluxcore wire, it usually has an asterisk under the parameters table that tells you to turn the voltage down if using an argon mix(ie. C25).

I have no problem with contrary if I need corrected, that's how we learn.

I have a mig welder and very seldom use it. I need to spend some time learning more about the process.

Len


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Hi guys, thanks for your input.

Here's a piccie of the underside of one of my 1.5mm butt welds...


...And the underside of a couple more...


On the upside I hammered the crap out of it and the steel bent first and not my welds lol...



The only other thing I can think.....

I am using an extension lead. A cheap one at that. Any bearing on it?

W B,
I'm not sure if you have a manual with your welder but I found a link to one online @ http://www.clarkeservice.co.uk/manuals/ ... -160en.pdf

You may need to time your wire feed speed to make sure your feeding out the correct amount of wire and not slipping at the drive wheels. Shut your gas off and squeeze the trigger and let it go for 10 seconds, then times it by 6 for inches per min. There are guys on here who can tell you if you're in the right ball park.

Len

Will do Braehill, thanks for the input

oh and ps, this is 100% CO2

LOL...Len, I found that pdf and posted it too....in the other thread.

Welding bear, Re-check your polarity and make sure it is correct for the wire you are using...that will also effect your penetration. I switched from a self-shielded fluxcore over to soild mig wire and forgot to change the leads around and it made a mess until I figured out what I had done wrong. Also keep your ESO(electrical stick out) fairly short with that machine. 1/4" to 3/8" ESO is all you need for that small diameter wire. ESO is measured from the end of the contact tip(not the nozzle) to the work.

Thanks mate.

TBH I haven't ever touched the polarity as ive only had it a couple weeks but I can certainly check how the factory have put it together,

oooook.... stick out.... my contact tip sits quite deep in my nozzle (lol welding terms are sooo loaded with euphemisms)

I simply screwed it in to the gun til it stopped. should I unscrew the CT til i get desirable stick out?

Welding Bear wrote:oooook.... stick out.... my contact tip sits quite deep in my nozzle (lol welding terms are sooo loaded with euphemisms)

I simply screwed it in to the gun til it stopped. should I unscrew the CT til i get desirable stick out?

You have it installed correctly if you screwed it in until it seated. The ESO is something that you as a welder can control while welding.
The stick out should be held as constant as you can(1/4" to 3/8"). Pull the trigger and then trim off the wire so that you can start with the correct ESO.

The machine is a CV machine(constant voltage) so if the stick out varies while welding(holding too far away from the work and back close again), the machine will have to hunt to keep the voltage constant. It will try it's best to maintain a constant voltage by varying the amperage.(keep in mind the laws concerning electricity are mathematical)

Also keep this in mind....longer stick out than recommended uses up the voltage to heat the welding wire and effectively lowers your voltage even though you have it set to #2/MAX.

To set up a machine like this...set your voltage first (#2/MAX in this case), and then adjust your WFS(wire feed speed) to feed enough wire into the puddle without the wire melting off up inside the contact tip. If the WFS is too low, it burns the wire off too short up inside the tip(ruins your tip), if the WFS is too fast, it creates excessive spatter and wastes filler metal as it jams the wire into the molten puddle and splashes out all over.

Thanks mate

If I was to have 3/8'' (or approx. 10mm) from contact tip to work piece I'd have the nozzle right on touching the metal....that's how recessed my contact tip is! lol

At the moment to get the best controllable weld I'm holding the nozzle approx. 10mm from the workpiece. Thus with the recess of the tip I may be looking at about 16mm between contact tip and workpiece.

I THINK I'm getting the distance constant most times and I keep my left arm under the gun to support it.

I wonder if a longer tip (I presume they sell them) would really help bearing in mind I saw one guy on the net say the contact tip should stick out proud of the nozzle (thus changing totally his ESO)..... I hope that makes sense..?

That is way too much stick out for that small diameter wire. Is the nozzle pushed up onto the gun as far as it will go? You may end up having to grind the end of the nozzle back some(I never had to do that before).

Well.... I say never, but to get close enough to the joint on a tight weldment, I did grind the nozzle to fit the end of the gun up in a tight corner to complete a weld.

Yeah, ill get a pic of it in a sec.

yeah the nozzle is done up right to the point its snug to the guns shroud.

I would have thought you could buy longer contact tips instead of havig to grind the nozzle? although im pretty proficient with the grinder andLOVE using it.

Here's the image of tip against nozzle...



You can see I got a good 5-6mm of recessed tip.

Should I be making the tip flush with the nozzle end... or just sticking out a couple o' millimetres?

Welding Bear wrote:
You can see I got a good 5-6mm of recessed tip.

Should I be making the tip flush with the nozzle end... or just sticking out a couple o' millimetres?

Do you have a Northern Tool over there or a local welding supply? I'm wondering if it uses the same contact tips as a lot of the welders over here uses(ie Miller/Hobart 135amp machine) use the same tip and I can get them at Lowes, Northern Tool, Home Depot, Harbor Freight, and of course my LWS. Maybe you can find one that fits that is longer to get you closer to the end of the nozzle. Not sure how you see where you are pointing the arc with that setup without making the stick out way too long.