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Safety glasses or goggles are a must!

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    Safety glasses or goggles are a must!

    Unless you want to become a one eyed pirate, use your laser protection glasses and make sure they are rated and stamped with the OD at the wavelengths your laser can produce. Warning; Some cheap laser glasses and goggles from China may show OD ratings which are fake, know who really made them and do not rely upon cheap could-be fake glasses. In my opinion, for low power lasers under 100 mw I would not be afraid to use genuine properly rated OD3 glasses at the wavelengths of concern as they should attenuate the power by a factor of 1000.

    For higher power or pulse lasers do your own research outside of this forum from professional resources for what you should use. I prefer an OD rating which attenuates the power by a factor of at least 10 times more than needed to protect against a direct hit and take solid measures to be sure I do not get a direct hit by the beam. Laser protection glasses or goggles (which I prefer) are not normally designed to protect against direct high power hits as the beam can melt through them fairly fast.

    Note: Optical density, or O.D. refers to the attenuation factor of the filter to the base 10. Therefore, a filter with an OD of 2 attenuates the laser by a factor of 100 (102), an OD of 3 attenuates the laser beam by a factor of 1,000 (103), an OD of 4 by a factor of 10,000 (104).

    Disclaimer, I am not a laser safety expert, do your own research from proper resources to determine if my advice is correct or not for what you are doing with lasers. See:

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    Copy, snip: - Note, lasersafetyfacts has been contacted and asked for permission to use their page here, waiting for an answer.
    Laser Safety Facts

    Helping the public safely use consumer lasers with visible beams

    Laser classes

    Lasers are classified for safety purposes based on their potential for causing injury to humans’ eyes and skin.

    Most laser products are required by law to have a label listing the Class. It will be listed either in Arabic numerals (1 2, 3R, 3B, 4) or in Roman numerals (I, II, IIIa, IIIb, IV). At this website, we primarily use the Arabic numerals, for convenience.

    For visible-beam consumer lasers, there are four main classes. Each is described in more detail here: Class 2, Class 3R, Class 3B and Class 4. The first two Classes are relatively safe for eye exposure; the last two are hazardous. The chart below shows how the eye injury hazard increases as the laser’s power increases.

    Click chart for larger view

    Click chart for larger view

    The detailed information given below is for laser light that is visible -- between 400 and 700 nanometers -- and for an unintentional exposure of less than 1/4 second. Consult other sources for classifications of infrared and ultraviolet lasers, or other visible-light exposure durations.

    Laser Classes (visible light only, unintentional exposure <0.25 seconds)

    Click table for larger view

    Click table for larger view

    For more information about a particular class, click here: __ Class 2 __ Class 3R __ Class 3B __ Class 4

    See also the Laser Hazard Distance Chart. This shows the distances at which various consumer lasers are eye, skin, and fire hazards, and are visual interference hazards: flashblindness, glare and distraction.

    For information about laser classifications in general, see this page from Rockwell Laser Industries.

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