Silly newbie question I guess ...

[RobF]

Hi Guys

I finally got my Mig up and running after getting a bottle of posh gas for it etc.

All I need to do now is to teach myself to weld

I can weld nice beads on flat plate and on some tube.

I set the settings for the tube 25mm diameter x 1.6mm ish thick. I then tested on my test bracket which is a bit of 3mm plate - ok bead on there too.

So now lets weld a dummy inch by inch bracket of the plate to the tube.

When I was elding the tube or plate I got a nice bacon sizzle sound - when I tried to weld in the v between the plate and the tube to attach it I get spit-splat-fart-pop ... no bacon sounds of any description.

What is the obvious mistake I am making ?

TIA

 

[malcolm]

I'll make a stab at the obvious mistake: your current is too low. Less obviously your wire speed is too low as well.

Angles are funny things. Let's say you butt weld 1.5mm sheet to 1.5mm sheet - your current is set to the second lowest setting most likely. You've got to heat up 2 bits of 1.5mm sheet from the ends. But if you weld 1.5mm sheet end on in the centre of another bit of 1.5mm sheet you've got to heat up 3 bits of sheet from the ends - the bit at 90 degrees and the two bits that make up the sheet you are welding to (if that makes any sense). So Setting 3 would probably be the one.

Upping current would require more wire speed as normal, but extra wire speed is also useful for getting the arc right in the corner rather than arcing against the sides away from the joint.

I tend to replicate the real weld as closely as possible (angles, orientation and thicknesses) with test pieces to get the settings right before welding the real thing.