Where could I get a good welding mirror for pipewelding? I am looking for something that has a magnetic base or clamp, and a mirror holder that I can easily get replacement mirrors in and out of.
You might get a cheap magnetic indicator base from MSC, ENCO or Harbor Freight and adapt it to hold any type of mirror You can get cheap, including bicycle mirrors.
I switched from standard type mirrors to the gold coated welding lenses. Cheap, they can take a fall and I can trim them as needed for size/space constraints.