assume theyre monkey metal ...cant see it working , but yeah good idea if they made from something reasonble
Cut both the fittings shown in the first picture through the hex part where the spanner fits and then just weld the two bits you want together.
Spray the thread with anti-spatter before welding. If you do get a spat stuck to the thread it can be filed and follow the thread round with a junior hacksaw. Plenty of ptfe tape before screwing it in.