I successfully cut/disassembled cameras to remove the infrared filter, to make viewing IR lasers and heat radiation possible - now I want to block out all visible radiation to make a pure IR cam. Recommendations? Or is it a waste of time?

Because the IR lasers look indistinct to normal visible lasers I shot a photo of an otherwise invisible stove: https://ibb.co/h1Cd7BXC

It obviously works very well up to at least 1000-1500 nm - so I thought I could block out everything below ~700nm to get a pure IR camera - is that feasible?

Are there commercial cheap options available to filter everything up to ~700nm?

For a short tutorial:

The IR filter is a red-pink glass pane, typically located directly above the digital sensor.

Old cheap digital cameras were the easiest, just use a razor blade and remove it. Full functionality.

Smartphones and similar stuff are kinda tricky: you might damage (=shorting) the sensor just by trying to crack it open, catastrophically damaging it if you're not careful.

Also the autofocus electronics have to be cut to access the filter/sensor, so if you're not re-soldering it you won't have any ability to focus it anymore.

Always make sure to clean the sensor before reassembly, especially the smartphone filters can't be removed without cracking, and the shards will show up if not cleaned up (see my linked example).

Use super glue to reattach smartphone/webcams. Re-solder the connections if you need full functionality. (Either way it's a cool Experiment that leads to funky photography).