Interesting scaling problem: A kid should probably start out making a 6 inch mirror which only weighs maybe a pound. But mass goes up by a factor of a cube wi

Interesting scaling problem: A kid should probably start out making a 6 inch mirror which only weighs maybe a pound. But mass goes up by a factor of a cube with diameter... the linked article 15 inch mirror blank is likely 75 to 100 pounds? You can buy special thinner blanks but it gets to the point where in a wet slippy fingers situation it doesn't matter all that much if 60 pounds or 80 pounds lands on your toe when you drop it. Something the other responder didn't mention about wet grinding is after you finish with a coarser grit, perhaps 200 grit, you have to clean the mirror and the local environment VERY completely or else when you switch to finer 400 grit even one tiny grain of 200 grit will ruin and scratch up the attempt at a 400 grit polish. So its kind of self-fixing in that if you're not screwing up, there will never be aerosolized grit because your working area will be very clean indeed. Its a very clean hobby, compared to most.