sup /DIY/ so ive got this project and i have to explain the

fuck off mate do your own homework

Here's a good start

https://en.wikipedia.org/wiki/Welding

>>915826
This.

How hard is it to research online?

>>915814
are you a nigger?

>>915814
GOOGLE IT.

>>915814
They are both the same in that an electric arc melts the wire/stick and (hopefully) melts most of the way through the metals to be joined.
Gas and the flux on what you are calling arc welding do the same thing, keeping oxygen away while the weld cools to avoid it burning.
Gas is more expensive, but a nicer looking weld with little or no slag to chip away. Its only disadvantage, besides price, is that flux protects more if you weld outdoors in a strong wind.

>>917087
OP may be referring to oxyfuel welding there rather than gas-shielded arc welding. Of course, OP clearly knows next to nothing about welding, so it's anyone's guess at this point.