Hi,

Making a thin mirror is possible, but as pointed out by Rick, you will need a special mount (not hard to build) to support it in your telescope. More importantly, grinding and polishing such a thin disk can result in a mirror surface with a bad case of astigmatism if you are not careful. For this reason, my mirrors have been full thickness. Yet, there are ATMs who have succeeded in making thin mirrors. Check out these sites:

http://zebu.uoregon.edu/~mbartels/largthin/largthin.html

http://www.geocities.com/CapeCanaveral/3505/atm.htm

Good luck,
Bill
http://www.my.treeway.com/observatory1