"isn't the slag formed during welding largely a result of the flux on the rod?"
marzipan9 the flux on a rod is a welding rod. Welding meaning to fuse to bits of metal together and yes the flux on the weld area is the from the flux on the rod to protect the molten weld from the atmosphere while it cools.
THAT slag is from a oxy-acetylene or oxy-LPG cutting tool. All it is, is just a worker thats cut it for the purpose of removal like what would be done thousands of times when removing the collapsed buildings.
When you cut thick steel its always best to do it on a angle because the cutting edge is sharper thus making it more conductive to the heat thus creating less chance of blow back ect.
Trust me! I was a boilermaker for 17 years.
If anyone looks at that picture as proof of a conspiracy they really are gone!!!
