Cutting and shaping dielectric mirrors?

[macona]

I need mirrors. Specifically mirrors for 355nm and 1/2" dia for the holders I am using on the laser cutter I have been building. The problem is the ones I have are about 1" x 1.5" rectangles.

So I am thinking of cutting the mirrors to rough shape with a diamond ring saw and then gluing them down to a plate and use the cnc mill to machine them to diameter.

What I am worried about is the coating. Should I cover it with something like kapton tape before hand to protect it while machining? Or will the flow of coolant with grit be of no consequence to the coating?

-Jerry

[LaNeK779]

hey Jerry, have you cjecked this product out?

http://shop.stanwaxlaser.co.uk/first-contact-48-c.asp

Maybe it is the answer for you. Coat the optics with this, then cover it with kapton tape and i think you will be good to go (and keep the optics clean with no signs of glue etc)

[macona]

Looks interesting. Too bad they dont sell it an any smaller quantities than 45ml at a time on the US site. Spendy!

I have a damaged mirror to test and see what happens. Nothing to loose.

[LaNeK779]

I am sure Rob @ stanwax can send it over to you. Send him an email or a pm ( user " stanwax " )

[planters]

A cheaper and probably better protector is bee's wax and or paraffin. In optical shops that work with astronomical optics there is a lot of back and forth optical fabricating then machining then fabricating etc and the vulnerable surfaces would be covered in a layer of wax which is easy to remove with the optic on its side and a little heat. Final cleaning with an organic solvent removes the wax. The thickness of the wax can be adjusted depending on the aggressiveness of the machining.