The location of my leak made a pipe clamp or plumbers tape impossible. I tried wrapping a piece of rubber gasket around the pipe and securing with hose clamps that I could feed between the pipe and the floorboards, but the water pressure made a mockery of this. I'm well versed in two-part epoxy putty for its artisitc/hobby/craft uses, so I went looking for something in that vein. I found one that is water-impermeable, and certified safe for using in contact with potable water. It gets my seal of approval as it held under pressure and there was no leakage for the two days that it stopped the gap.
PC-Products Plumbing Epoxy Putty.
I should learn how to solder copper pipe someday, but this was not the time to learn, I decided. So I called in professional help. None other than the world's famous came to my assistance:
We're back up and running, all ahead full!