genarro wrote: ↑17 Mar 2022, 15:00
why would you brush down the owidation. you dont have to make it look pretty.you just have to make it functional
Contaminants like that give crack formation/propagation areas under heat/stress cycling. Probably not much of an issue for a single race weekend though. You usually scrub off that heavy oxidised area and let it reform it's natural oxide layer instead, they're not that bad as you can see from the weld bead - dark blue in places ain't great but it's heavy straw for most of it which is okay usually. But it's usually done as a matter of course.