Help - struggling with penetration

[gaza01]

Need a bit of advice pls.
Currently they are just tacked in place but I'm welding in some camber and toe adjusters onto my 1987 5 series subframe but struggling with penetration into the subframe. The new mild steel welds ok but the subframe...its like its a tougher steel? The adjusters are 2.5mm thk and the subframe is 3mm thk for reference.

I welded some 5mm thk bracing to other areas on the subframe and had to turn the voltage up to get penetration but then that led to undercut in the 5mm.

Suggestions pls.

 

[Munkul]

Voltage doesn't give penetration, amps do.
More amps will also fill in the undercut.
Up the wirespeed.

 

[Rrobson]

What set do you have? Is it powerful enough? Circa 120a for the above and getting on for 200a needed for the 5mm you already welded.

 

[Barking Mat]

Pump up the jam, no, I mean amps.

Welds are cold.

 

[gaza01]

I'm using a rtech 180 and the recommended setting for 4mm so already higher than the setting for 3mm...but i'll increase the amps some more. Here's a better pic of the undercut on the bracing.

 

[frank horton]

seems to be an important job for for a learner.....
perhaps get it done

 

[Munkul]

I'm using a rtech 180 and the recommended setting for 4mm so already higher than the setting for 3mm...but i'll increase the amps some more. Here's a better pic of the undercut on the bracing.

you'll often burn away an edge on a lap joint like that, its the nature of the joint, its a bit trickier than a fillet. You should point the gun a bit more to the bottom plate as that's what needs the heat. the top plate will get plenty heat regardless.

Fillet joints take more amps than lap joints, I thought you were still on fillets. you can turn it down again for lap joints

 

[Wozzaaah]

seems to be an important job for for a learner.....
perhaps get it done

Why? They're not going to go anywhere once everything is bolted up.