Welding Tips and Tricks

Can anyone help me out? Someone sent an aluminum part that was already welded, it is supposed to be TIG welded but this looks to be MIG, they wanted me to run a bead on the backside but I've returned the part... My question is how is there color inside the weld? I've only ever used a spool gun once so I don't know if this is a common thing? But I cannot find anything online that would indicate that aluminum is even able to have a colorful oxidation just from welding. Let me know if any of you have ever witnessed this?

Loos like they attempted DC TIG welding with helium, based solely from what Ive seen on YouTube vids.

the lack of etching says not mig.
it kinda looks like tig really cold and way low on gas. a bit of etching there but it disappears for a lot of it. color could simply be contamination and lack of gas coverage.

either way its a good call to turn it away.

My brain goes straight to silicon bronze or alumna bronze filler based off just that pic.

Only way I know to get a gold colour to an alum bead.

Even when I weld dirty old cruddy aluminium I still don't get a gold colour. Just lots of black and that lovely burnt looking greyish blue colour that alum likes to do when it has bad gas coverage or gets overheated.

Toggatug wrote: ↑Tue Sep 06, 2022 12:55 pm My brain goes straight to silicon bronze or alumna bronze filler based off just that pic.

Only way I know to get a gold colour to an alum bead.

Even when I weld dirty old cruddy aluminium I still don't get a gold colour. Just lots of black and that lovely burnt looking greyish blue colour that alum likes to do when it has bad gas coverage or gets overheated.

Okay this is also what I feared as well, that they were not using the correct filler material. I too have never got any color in my aluminum welds, merely different shades of grey varying to black, never gold.