Re: [ATM] mirror grinding

["Mel Bartels" <mbartels@bbastrodesigns.com>]

> I've heard rumors of using a sandblaster for getting a hole done for a
> mirror but haven't heard much about it.  Brave people to do a curve that
> fast in the glass as you can eaisly overdo it in an area and then have to
> drop the rest of the surface down to compensate.  However, that would 
> indeed
> be a nice fast method of removing a lot of material.
> A lot better is the using of a long arm with a toolgrinder or other drive
> for a 4" diamond blade of the $10 for 3 blades that HF often has on sale 
> to
> swing back and forth and do the ROC pregeneration that way.  No need to 
> put
> the mirror on a lathe although turning it on a MOM turntable would make 
> the
> curve a bit more even wedgewise than just putting the glass in a fixture 
> at
> the working end of the long spar.


I've tried both, and both were difficult to control.  You still have to 
grind a smooth curve in even if all goes ok.  So I didn't find that either 
saved any time, when you count the setup to get the sandblasting and/or 
toolgrinding arm going.  It's real easy to gouge a 1/16 inch deep spot where 
it's not supposed to be in no time.

Mel Bartels

_______________________________________________
ATM mailing list http://www.atmlist.net/