mirror making

Hello,
I am currently considering grinding my own mirrors.
I would like to grind a 8" f/8 mirror first. Then if all goes well step up to a 12.5" f/6 or f/5. My question is plate glass vs pyrex, as well as how thick. The plate glass is cheaper and I have heard retains less heat than the pyrex (the thinner the glass on both types the better). Is it feesible for a novice to turn 3/4" or 1" plate blank into a mirror with wavefont 1/20 or better. I know the pyrex is sturdier and would not have to be climate controlled in the final stages like the plate glass, but from a pure optical stand point which is better???
I have also found a nice web site mirrorkits.com. Has anyone ever dealt with these people and are their mirrors or blanks up to par? I have also heard of quartz blanks and fused silica, what's the story with those? I am looking to create the best quality mirror possible. Any other suggestions or comments that will aid me in doing so is strongly encouraged.
Thanks
Todd

Todd,

Either Pyrex or plate will work fine. A bigger issue might be starting with a thin blank. One inch would be OK, but 3/4 inch might be pressing your luck. For an 8" mirror, the difference in cooling between a standard thickness blank and a thinner one is not huge. Thin blanks become more desireable in larger apertures.

As to a 1/20 wavefront mirror, I think the vast majority of these are little more than pipe dreams (I assume you are talking PTV). A true 1/8 - 1/10 wavefront mirror, with a nice smooth figure, leaves little to be desired.

Clear skies, Alan

"I am looking to create the best quality mirror possible." With that being the most important point and money(as with your 8" mirror) not being an issue, then quartz or another ultra low expansion material is really the best. The ability to test immediately after a figuring session and being able to rely on the results as accurate(due to no surface changes) is a big plus with the ultra low expansion materials. Just a personal opinion formed from working large, thin mirrors of Pyrex, plate, and quartz. Hope all goes well with your first mirror. You'll have a great time regardless of the material chosen and will learn a lot and that's what first mirrors are for.