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  1. #1
    MAD's Avatar

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    Default Exposure Box Explosion!

    first i want to give out mega-thanks to everyone who posts, it has helped us out a lot. eveyone offers up great ideas, positive feedack and concrete criticism, the forum rocks. we are post-virgins, so this is our first time.

    i built an exposure box... and it exploded.

    box specs:
    48"x36", 36" deep, three 500w haologen work lamps, 1/4 glass top.
    the light source is on bottom of box, roughly 36 inches away from glass.

    here is what happened:
    oiled up laser copy of art using mineral oil. paper became like vellum, pretty transparent. then we stuck oiled postive to screen and placed on glass. we put a black blanket ovet the entire top then put some yellow page books to ontop of that to hold positive against screen and glass.

    we had done some exposure time tests, at 18 min. the image washed out but left a ghost of the oiled paper shape, (not sure if that is normal). during wash out the emulsion started to soften up and breakdown.

    the next test was 25 and 30 min. with slightly better results. image washed out fine, took a little bit, but washed all out. we noticed we had less of a ghost shape left by the oiled positive, but the emulsion started to soften up still.

    the next time test we where going for 35 min., and BOOM!... no more exposure box.

    the 1/4 inch glass shattered and fell onto our lamps. our lamps went bye-bye.

    we always expect failure, so we know we can rebuild. any advice on the situation would be great. should lamps be closer? should we use flurecents instead? thicker glass? are we oiling positives wrong?

    we'll be chewing on hot oiled shards of glass all day.

    i hope our first post was as good for you as it was for us.
    thanks in advance.

  2. #2
    Premium Member
    Unitus's Avatar


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    Mar 2002
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    Default

    i think you need more light, and a shorter exposure time. the only real lightbox i've seen/used, is not as deep as yours, but about the same size otherwise with 8 flourecents and about a 5 minute exposure time.

    ???

  3. #3
    jasoncross's Avatar

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    use flourscent...make sure your glass is supported on all edges...glass has low elasticity so when you bend it past a point...it doesnt return...it breaks...as you are now aware

    with 12 48" flourescents on 6 ballasts using F40T12 BL and NOT BLB lights my burn time is 45 seconds using transparency and 90 using velum my lights are about 5 inches from the glass. glass is 1/4".

    email me and I will send you the plans for the box that are somewhere on this site.

    goodluck and happy hunting,
    jason cross

  4. #4
    MAD's Avatar

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    using F40T12 BL and NOT BLB lights
    i assume those are product numbers?
    are there any other names that i should look for when looking for flourecent lights, like "Blacklight" or "Super UV" or "Real Sun Light"? what does the "BL" and "BLB" stand for?

    looking at fixture like this to work with:
    Commercial Electric 4 Ft. Shop Light

    [/img]

  5. #5
    gun sho's Avatar

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    hey MAD,
    are you from Narragansett? i grew up in South County. Moving back to Providence in a couple weeks. if you need printing advice, i'd be happy to help.

  6. #6
    jasoncross's Avatar

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    BL is blacklight UV and BLB is black light blue...like the disco club style.

    the F40T12BL is a generic name...most manufacturers use the same numbering for their lights.

    the blacklights i have work in a shoplight ballast exactly like you have posted.

  7. #7
    MAD's Avatar

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    -yo jason,
    you rock. the plans and photo are awesome. mucho thanks!
    the center supports will def. help. will try to install new light system this week.

    - gun sho
    born & raised in gansett. let's start a south county gang.
    get in touch anytime.

  8. #8
    jasoncross's Avatar

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    not a problem...fill free to contact me if you run into any issues.

    again - best of luck,
    jason

  9. #9
    MAD's Avatar

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    after the explosion...


    glass is yummy!

  10. #10
    jasoncross's Avatar

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