I had thought of doing something similar myself. Now running tubed means this is not necesary, but I think Hustler is right. They are a bastid to break partly because a flat tyre is so flexible, but I think just a simple G-clamp would work with out the welding bits. Or you could use a couple of bits of wood 10mm thick to spread the clap affect (depending how wide your tyre is.
If in doubt, get the clamp and try it on a loose wheel, then take it to a tyre shop or pertrol forecourt to re-inflate... S'wot I recons...
Adventure: it's an experience, not a style!
(so ride what you like, but ride it somewhere new!)