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Conventional Fixtures Super Heat Shield Help...

Discussion in 'Lighting and Electrics' started by Chaos is Born, Jun 28, 2007.

  1. Chaos is Born

    Chaos is Born Active Member

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    Ok, has anyone here had experiance with R1991? Roscos Super Heat sheild?

    We got some in today and i am using it in our Source 4 750w 19, 26, and 50deg... the gel seems to be burning out just as fast as before if not faster though the tests that i have run...

    Rosco sugjests having 1/2" space on either side of the heat sheild to allow for ample breathing room for the heat to be released.

    test 1: Gel without sheild: burn out time 40 seconds

    Test 2: Heat sheild in slot 1, gel in slot two: burn out time 30 seconds...

    Test 3: Heat sheild and Gel in same slot: currently going on 5 mins with some color changes but no burns...

    Any sugjestions?

    Edit: Ok, after 10 mins of Test 3 i let the Gel cool down and then took a look at the damage, there were no complete burn throughs, only some spots where the color had disappeared and some color had transfered onto the heat sheild.
     
    Last edited: Jun 28, 2007
  2. icewolf08

    icewolf08 CBMod CB Mods

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    What unit are you testing this in? The 36˚ and 26˚ are notorious for having specific lens positions that cause the gel to burn up almost as soon as you put it in. You may have better luck changing the focus, or use color extenders. I had a problem with gel burning during hang for Les Mis two months ago, all it took was a few color extenders and all was good. If you don't have color extenders you can always tape the gel to the end of a top hat.
     
  3. Chaos is Born

    Chaos is Born Active Member

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    Testing is taking place in a 26 degree which is the unit that i will be using the colors in the most. I unfortunetly don't have any top hats... (don't ask why, i've only been here three weeks) but i have a whole bunch of half hats... And i don't have any color extenders either...
     
  4. Footer

    Footer Senior Team Senior Team Premium Member

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    check your bench, or tell the cheap person in charge to go but some color extenders.
     
  5. Sean

    Sean Active Member

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    You could also try Apollo Gel Shield. It isn't cheap at ~$40 per sheet, but worth it for scrollers and units that might be hard to reach.

    We ended up buying a bunch, and taping it into spare gel frames with blacktak. We just keep using it until it ages too much.

    With the Gel Shield, you MUST make sure the correct side faces the unit. You can tell by using a multimeter set to Ohms (Resistance). The side that faces the lamp is actually partly conductive. Not enough to give you continuity, but enough that you'll see it on the meter.


    In a pinch you can also tape an oversized piece of gel to the front of the unit--you know, make a tent out of it. It will give you some more space between lamp and gel.

    --Sean
     
  6. NickVon

    NickVon Active Member

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    Whats the recommended way to use the Apollo Heat shield? Are two separate gel frames , one just in front of the other enough? (i'm looking to use it in S4 Par's with Wide lens's) Are two Gel frames next to each other sufficient, or should i use a Color Extender for the Color gel its'elf, and the regular gel slot for the shield? the little instruction sheet doesn't really specify how much "space" there should be between sheild and Gel.
     
  7. zmb

    zmb Well-Known Member

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  8. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Speculation only, and not necessarily based on fact or experience:
    Using both color frame runners of a fixture is better than one color frame, but not as good as a color extender or double color frame.

    From Rosco US : Filters : Protective Filters :
    Note that Apollo's GelShield is a similar product to Rosco's Thermashield, which doesn't specify an exact minimum distance either.

    Since you're using a wide-beam fixture, even a 3" color extender may encroach on the beam/field, so I'd consider building your own, following the article linked to in the wiki entry color extender.
     
  9. Kelite

    Kelite Apollo Staff Premium Member

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    So much of the results depend upon the bench focus of the lamp, which is out of the manufacturer's control. If the light beam of the fixture converges at the point where the Gel Shild is placed, the hot spot is much more concentrated. A wider beam at the color frame is a much cooler beam.

    The reason the multimeter is helpful is due to the fact that Apollo's Gel Shield is a dichroic thin-film coated product, with protection at the point of the coating itself. When light (heat energy) contacts the dichroic coating prior to the substrate, maximum performance is attained.

    (* Use of atmosphere- fog, haze, smoke- will allow the user to see where this beam convergence takes place and make necessary adjustments for extending the life of the color filter.)
     

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