Gas shielded only

[cpw]

I've just read the mig welder buying guide and there is one thing that puzzles me

In the "Gas vs Gas less" section it says

>so unless you know you'll only want to weld with flux cored wire it makes sense to go for a welder that can do both, or a gas shielded only welder.

I can understand that there can be gas less only welders but does this mean there are gas only welders in which you can't use flux cored wire?

Let's say I have a gas shielded welder and I'm out of gas but I do have some flux cored wire, what would go wrong if I used that wire?

 

[cpw]

It seems that for no-gas welding the torch needs to be negative whereas for gas welding it should be positive so to answer my own question unless a welder can reverse the polarity then it can be considered fixed gas or no-gas only.

Would like confirmation from an expert that this is the only difference.

 

[shenion]

Yes, being able to swap the polarity is the main difference.

Welders that do gasless also have knurled rollers, gas-only ones would preferrably have smooth grooved rollers. Most hobby welders use knurled anyway though.

 

[cpw]

Thanks, always nice to have confirmation.