Welding thin sheet, flame with no puddle

[pquinton]

I consider myself very much a beginner, and I'm struggling to understand how to correct a frustrating problem. I'm MIG welding a patch I've made from 0.9mm cold rolled steel onto my MK5 Golf (sill repair).

I've been attaching the patch (butt) using tacks and filling in the gaps, a tack at a time. The problem I'm having is that a good percentage of the time I get a flame between the tip and the panel and no puddle. I'm running the welder pretty low. It's a Lincoln Bester 190c running 0.6mm wire on CO2. Wire feed is around 4 (almost at the minimum) and the voltage is between 13 (minimum)-15v (I keep tweaking it). The welder also has an induction setting which I've got almost maxed out.

I'm trying to avoid blowing the edges of the patch/car body, which is the other issue I keep having.

Is the flame due to a voltage issue or something else?

Thanks in advance,
Phil.

 

[tigdlo]

Is the flame due to a voltage issue or something else?

Sounds like a long arc, there should be no fire is you are doing it right, try turning the wire speed up. Have you set the welder up on practice pieces? Set your practice up in the same position you will be welding on the car, eg. vertical or overhead. Post some photos of both sides of your practice along with the settings you used.

 

[Dozzer]

welding very thin car panels is a bit counter intuitive, rather than trying to run the lowest power & wire feed, you need plenty of power and wire.
the spotting technique needs to get the weld pool melted & filled in a very short time.
If im doing sills i use 0.8mm wire with 17+volts and one a 1-10 wire feed around 3-4.

And if its cold rolled, make sure you have got rid of the mill scale as that acts like an insulator and will slow the weld pool creation down.

There are some brilliant youtube vids on welding car panels, may be worth just taking some time to watch.
Oh and practice is your best friend. try on some scrap before getting frustrated with the work.

 

[pquinton]

Sounds like a long arc, there should be no fire is you are doing it right, try turning the wire speed up. Have you set the welder up on practice pieces? Set your practice up in the same position you will be welding on the car, eg. vertical or overhead. Post some photos of both sides of your practice along with the settings you used.

Would you keep the voltage fixed and increase the wire speed? I've practiced the test welds on the bench and managed to not have the issue. It only occurs when I do it on the car. The only difference I can see is on the bench I'm welding from above whereas on the car I'm welding side on. The other issue is on the bench I'm welding 0.9mm to 0.9mm and not 0.9mm to car body work (which is ground back). I've checked the earth with a multimeter just in case I have bad earth, but that's good as well. I've got pictures of the welds I've done on the car...

 

[pquinton]

welding very thin car panels is a bit counter intuitive, rather than trying to run the lowest power & wire feed, you need plenty of power and wire.
the spotting technique needs to get the weld pool melted & filled in a very short time.
If im doing sills i use 0.8mm wire with 17+volts and one a 1-10 wire feed around 3-4.

How do you avoid blowing through the metal? I keep getting the odd hole and I'm only pulsing for a fraction of a second, a second at the most?

I've watched a fair few youtube videos, but it's a struggle to find ones that show the actual faults as they happen and how to fix them. I've found a few that show how to do auto body work patches but the welding part either works perfectly first time or they show you before and after...

 

[Misterg]

I've practiced the test welds on the bench and managed to not have the issue. It only occurs when I do it on the car. The only difference I can see is on the bench I'm welding from above whereas on the car I'm welding side on.

I'm guessing that the end of the wire is just sitting there, hissing and building up a blob? The arc is struck, but it's burning the wire back as fast as it's feeding. Yes, turn the wire speed up. Position makes a difference - you'll need to increase the wire speed again when you're upside down.

How do you avoid blowing through the metal?

If you haven't got any metal going into the puddle, the sheet will just burn away - more wire speed (and practice).

 

[Dozzer]

How do you avoid blowing through the metal? I keep getting the odd hole and I'm only pulsing for a fraction of a second, a second at the most?

I've watched a fair few youtube videos, but it's a struggle to find ones that show the actual faults as they happen and how to fix them. I've found a few that show how to do auto body work patches but the welding part either works perfectly first time or they show you before and after...

As @Misterg says, you need to get the material in to stop the hole forming. its a very fine balance of power/heat and material. to much heat it blows through, getting the torch in the right place with the right wire feed is something that does take a bit of practice, but im sure you will get there,

 

[Shedendman]

Pure Co2?
Hummmmmm,not saying thats a no no,but its making life hard for yourself(its a hot gas,so to speak),get some argon+Co2
Dump the 0.6 and get some 0.8
Up the wire speed but keep the power as is,kill that induction setting,you can play with that later
Check the tension on the wire feed you might not have it tight enough,so that leads to it slipping,but dont over do it
Another reason for blowing holes is not alternating your tacks think of a clock,start at 12 do 2-3 tacks then move to 3,few more tacks then 6............and so on
There a load of other factors to take into account,stick out,distance,joint fitment,you're doing a patch,the patch might look clean,what your welding to might look good from the outside,but whats on the other side,if thats rusty and get into the weld pool its not having it
I'll say what other have said and will say after me,practice,practice and practice until it sinks in
Remember,its not the welder,its the welder

 

[Wozzaaah]

If you’re getting a “flame” at the tip but little to no metal transfer then most likely you have Insufficient wire feed speed for the selected voltage. As long as your wire is clean and the liner and tip are both good, up your wire feed speed or reduce your voltage. Either way, get some thin sheet to dial in your settings on before attempting any body repairs.

 

[tigdlo]

Would you keep the voltage fixed and increase the wire speed?

You will need to dial in the wire speed for voltage, if you don't get the weld you need then you try a different voltage and dial in the wire speed for that new voltage, repeat until you get the weld you want.

I've practiced the test welds on the bench and managed to not have the issue. It only occurs when I do it on the car. The only difference I can see is on the bench I'm welding from above whereas on the car I'm welding side on. The other issue is on the bench I'm welding 0.9mm to 0.9mm and not 0.9mm to car body work (which is ground back). I've checked the earth with a multimeter just in case I have bad earth, but that's good as well. I've got pictures of the welds I've done on the car...

Measure the steel thickness on the car, you can grind the edge of the 0.9mm to match, set it vertical and practice first, it's easier than fixing sub standard welding on the car. Show us some photos of the practice, I don't think thewelding on the car will tell us much, might be funny though.....