Results 1 to 8 of 8

Thread: Fog on the mirrors?

  1. #1
    Join Date
    Aug 2007
    Location
    Indianapolis, IN
    Posts
    196

    Default Fog on the mirrors?

    What kind of precautions do you take to stop fog/haze entering the scanner and building up on the optics?

    My home made scanner has a fairly well constructed air flow, but the fans still cause air to be sucked through the beam exit hole.

    Can this be avoided?

  2. #2
    Join Date
    Nov 2005
    Location
    Melbourne, Australia
    Posts
    3,677

    Default

    Quote Originally Posted by shobley View Post
    What kind of precautions do you take to stop fog/haze entering the scanner and building up on the optics?

    My home made scanner has a fairly well constructed air flow, but the fans still cause air to be sucked through the beam exit hole.

    Can this be avoided?
    Yep,

    If you seal the optics from the rest of the laser
    KVANT Australian projector sales
    https://www.facebook.com/kvantaus/

    Lasershowparts- Laser Parts at great prices
    https://www.facebook.com/lasershowparts/

  3. #3
    Join Date
    May 2007
    Location
    Milwaukee WI
    Posts
    1,355

    Default

    Usually you want a positive air pressure within the projectors case. That would cause only filtered air to be pulled in and keep the dirty air out. That doesn't entirely work all the time, because sometimes your projector is off and sometimes you dont have effective enough filters.

    Then you can do what Dave suggested. Many people use acrylic sheets (or plexi-glass) to enclose the optical area of the beam table so that no dust can go in or out. There are no fans in this area either.

    At the exit path of the beam there is a piece glass with an Anti-Reflective coating on it acting as the laser projector aperture.

  4. #4
    Join Date
    Aug 2007
    Location
    Indianapolis, IN
    Posts
    196

    Default

    Thanks - I do have the optics in their own "sub-chamber" but there's still some intake through the exit port.

    Can you give me a link to the kind of glass I should be using to seal off the exit hole?

  5. #5
    Join Date
    Jan 2007
    Location
    Yorkshire, UK
    Posts
    4,557

    Default

    Quote Originally Posted by shobley View Post
    Can you give me a link to the kind of glass I should be using to seal off the exit hole?
    Probably the cheapest and most convenient way is a Camera UV filter. They come in various diameters, just be careful to check the specs to make sure they transmit all light above ~400nm. Also, make sure that you get a clear multi antireflection coated one, some of them have slight tints on them which is something you definately don't want.

    Cheers

    Jem
    Quote: "There is a theory which states that if ever, for any reason, anyone discovers what exactly the Universe is for and why it is here it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another that states that this has already happened.... Douglas Adams 1952 - 2001

  6. #6
    Join Date
    Aug 2007
    Location
    Indianapolis, IN
    Posts
    196

    Default

    Thanks for the replies...

    Looking at the problem from another way, what would you recommend as a filter material for the fans? I've been using the black spongy stuff from PC supplies, but is there anything out there better for fog/haze filtering?

    Steve

  7. #7
    Join Date
    May 2007
    Location
    Milwaukee WI
    Posts
    1,355

    Default

    I've been thinking about buying a cheaper small HEPA filter.

    Haven't tried it yet though.

  8. #8

    Default

    http://www.laser-man.co.uk/2006/inde...d=51&Itemid=71

    if you look at this page, its from the last meet. fluff aka mark was showing me a laser that has a galvos ect sealed.

    its right near the top
    Eat Sleep Lase Repeat


    Aluminium Optic Mounts

    http://www.laser-man.co.uk/opticmounts/

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •