Three popular materials mirrors are made from are: Si (Silicone), Copper and Mo. Si and Copper have a performance enhancing coating and Mo does not. Mo mirrors lose about 2% power compared to Si and Copper, and they oxidize over time. When cleaned properly and often, both Si and Copper mirrors will last years, but will quickly become unusable when the coating fails. Si mirrors are common in CO2 lasers running 2000 watts. Copper is used for the highest power, up to 8000 watts. Considering price, quality, and durability, Si mirrors are the best choice for CO2 lasers under 1000 watts. Here is an informative video on Co2 laser mirrors: Why Si Mirrors are the Best.
Click on an Image Below to Purchase a Set of Si Mirrors:
How to Purchase Mirrors:
For most CO2 lasers, there are three mirrors. In most cases, the mirrors are all the same size. In order to determine the correct mirror size, you will need to remove one of the mirrors (follow the mirror removal instructions below). Once removed, use a digital micrometer to measure the diameter of the mirror. Take care when measuring the mirror so you do not scratch it.
The process to remove and install the mirrors is similar for each one.
Locate the mirrors. As mentioned above, there are three mirrors.
a. Mirror 3 is located on the top of the laser head.
b. Mirror 2 is mounted on the left side of the X-axis rail.
c. Mirror 1 is located in the laser tube compartment where the light beam emerges.
Observe the direction the mirror is facing. When reinstalling the mirrors, it is important they face the same direction as when they were removed (taking a video or photos might be helpful).
Locate the ring nut. Locate the ring nut holding the mirror in place and remove it by using a snap-ring tool.
Carefully remove the mirror. Gently push the the mirror out using a Q-tip, or your finger if you're wearing a glove. Do not touch the mirror, the oils on your fingers can damage the coating. Also, do not drop the mirror, because like any other glass mirror, they can chip or crack.
Here is a video that shows how to remove Mirror 3: CO2 Laser Alignment and How to Clean Laser Lens and Mirrors. The process is similar for the other mirrors.
The process to reinstall the mirror is exactly the opposite as the removal process.
Place the mirror back into position, with it facing the SAME direction as it was taken out. Take care to make sure the mirror is in straight and not at an angle.
Re-install the ring nut.
Tighten it until it is snug. Nothing more! Overtightening may damage the mirror.
How to Clean Your Mirrors:
Mirror x needs to be removed in order to clean them (follow the Mirror Removal instructions above).
Use only 99% isopropyl alcohol or acetone and soft cotton Q-tips, cotton balls, or lens wipes, to clean the lens. It is also suggested to wear powder-free, latex gloves.
Using a Q-tip, cotton ball, or lens wipe, apply the alcohol or acetone to the mirror and gently swirl around until it is clean. Never use paper towels or wipes. Here is a good video cleaning your mirrors: Laser Machine Maintenance: Mirrors, Lenses & More