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I ground an 8" mirror in my living room using Jean Texereau's book as a guide (i.e., pre-YouTube). A plastic garbage bag on the floor handled any wet grit. I don't understand what grinding dust you experienced - the grit is always wet. It was a great experience and thrilling to see the view even before the mirror was aluminized.


I'm truly sorry for your experience. A first mirror can be a lot of process and can indeed get a bit messy. With experience (or guidance, which is even better) you can work cleanly and avoid glass dust contamination of your workspace.


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.

Here is a recent groundbreaking example from Rik Ter Horst, a 10" f/20 kutter with toroidal secondary : https://www.cloudynights.com/topic/935825-a-250-mm-f20-kutte...

I did not do anything that impressive but enjoy my own set of non-standard scopes :

- A 8" f/3.5 hyperbolic primary + ross corrector

- a 6" f/2.8 with permanently mounted 4-element corrector

and am working on a 16.5" f/3.3 that will have a permanent Paracorr II lens group.

The only messy moment was my first mirror when I learned to cut pitch, but grit and glass dust itself are no problem thanks to the wet process.

You are right though on the last bits of figuring, it's a psychological challenge and my first mirror took 3 attempts over 18 months.


I'm not in the loop, are 14 inch or larger mirrors affordable nowadays?


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.


Do you have a reference on the health hazard aspect you mentioned? I'd heard fiberglass dust is very bad, but not regular glass.



Silicosis, but also fine dust is toxic when ingested. It can literally kill your cat or dog!


So don't have your pets in the workspace when it's not safe for them. What kind of lousy pet parent are you to not consider that? Also, wear the proper breathing equipment. This isn't some lame COVID anti-masking thread where wearing a mask says something about your politiks. It's working in a less than ideal environment, so take the proper precautions.

This is like telling people not to go outside because the dangers of UV radiation are too much. Deal with it. Wear protective clothing, don't hide in a cave. Some of us are brave enough and have the ability to judge risk/reward so that we left the cave, we crossed the oceans, we've left the planet. I'd hate to live in a world were nobody did anything risky because someone previously had a bad experience and stopped rather than looking at the bad result, making changes, improving the outcome the next time.


This is a bummer as I had been thinking about grinding my own for some time now. I'd like to know more about it and how I can protect myself.

The only part of the wikipedia for Silicosis that mentions glass is about manufacturing it and, even if it includes the grinding part, the reference it links to doesn't mention glass or grinding at all.

If you have more pointers or keywords about this subject, please let me know!


You're supposed to only grind wet, since the glass dust is a hazard. Grinding wet keeps it from being airborne.

Everywhere that I've read about grinding mirrors (and I've done a lot of reading) always says to grind wet. Any YouTube video you watch on the subject will also show them grinding wet.

When grinding a mirror you put water and grit on, grind until the grit is used up, wipe it off, and repeat. This is called a "wet".


The process uses wet sand. It's not hazardous.




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