I once drove my e30 for a few weeks with no interior, and one big sodding hole nearly exactly where this one is in my floorboard. It was funny for a bit, but then one day it rained. It rained a LOT, too. It wasn't funny anymore. You'd have thought I just got done swimming, and all I did was drive home from the gym.
That being said, let's make sure this guy doesn't have to go through that. So out comes the cut off wheel with its 13,500rpm of fury. Glorious.
Somehow in all the chaos of cutting, welding and trying to take pictures, I didn't secure a shot of the fully patched floor. Bugger. You can take my word for it though, he won't be experiencing any soaking wet drives from the gym.
It's never just one layer.
Save this. Gotta cut to gain access.
Use the throwaway as a guide.
Next, I'll make an origami swan!
This little welder is perfect for this job.