Mirror replacement upgrade

[Mike V Miller]

My laser tube went on the fritz and ordered a replacement. I figured since I was at it I would upgrade my optics. My question is what's the best mirror? There is Mo, Si, Gold, Copper, Silicone covered.. Geesh! Any imput anyone might have would be greatly accepted!

Thanks
Mike

[John Noell]

There are several previous threads worth exploring. Durability, reflectiveness, and uniformity of surface are key variables. There is not enough variation in the last two in my limited experience. I tried some Si mirrors (that look gold) and the slightest touch of methanol made the coating peel off. The Mo mirrors have been the best for me.

[Mike V Miller]

Thanks John. Been running this machine for 2 years and think it's time to upgrade .

[Dave Sheldrake]

GE have the best reflective index

MO are the toughest

CU are better if watercooled (and high quality)

SI are slightly above junk

K2 are junk

Above all buy quality, Mellor, II-VI are fine...RMI can be twitchy and many of the chinese ones vary from one day to the next

[Mike V Miller]

Thanks Dave! Your info is a big help!

[Dave Sheldrake]

also remember Mike, coated copper is little different to coated glass. True copper mirrors have a protective PVD layer but the reflective surface is copper rather than just plasma deposited gold on a copper substrate

I tend to go for GE on the expensive machines and MO on everything else as I have a habit of dropping stuff

[Ray Scott]

I basically just use the Molybdenum mirrors for everything. They are resilient! The only big downfall is the affinity to oxidize in high humidity or salty atmosphere. We just expect to replace the Moly mirrors on a yearly basis to keep them fresh.

The gold plated silicon is higher efficiency for reflecting the laser beam. The gold is also more resistant to oxidizing from humidity or salt. The downfall... I often find a way to scratch the surface. Be careful... The gold is quite soft as compared to the Molybdenum. Worst situation... Don't cut PETG with the gold mirrors. The PETG gas will react with th gold and turn the gold coating into gold glitter.

Thank You,