A bit messy is understatement. And finishing such project without a good guidance is almost impossible. At final stage a few bad moves can destroy week of work!
It is setting up newcomers for failure and burnout.
We made our own mirrors, because there was no other option a few decades ago.
But today mirrors are cheap, and they come with aluminum coating and rest of the telescope!
It's not about price, but enjoying the process, or making instruments that just are not commercially available. Amateurs are constantly pushing the limits of optical designs.
Just because this was your experience does not mean others should not try, and frankly, your posts suggesting others not try is disgusting. You're on a forum for people with a hacking ethos. That's pretty much the "hold my beer" mindset with a facade of classiness in front of it.
Also, rather than saying such negative things like "don't do it", you could have wrapped up your negative experience into a parable for people to learn from before embarking upon their own journey. Just because you didn't prepare for the results of grinding something to a fine dust/powder doesn't mean others won't prepare for that. Especially after what could have been a much more positive outcome from your negative experience. Don't be a downer.
This would be haha funny if you were trying to stoke that "don't tell me no" as reverse psychology.
We made our own mirrors, because there was no other option a few decades ago.
But today mirrors are cheap, and they come with aluminum coating and rest of the telescope!