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Strong 575 Followspot Burning Gels Please Help!

Discussion in 'Lighting and Electrics' started by soundguy99, Apr 6, 2018.

  1. soundguy99

    soundguy99 Member

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    Hi Guys,
    We Have 2 Strong 575 Follow Spots, 1 always burned Gels, The other one didn`t.
    We finally had to replace the one spots Bulb, just the other day, and after we did and adjusted the lamp, now it too is burning up gels.
    To be be Honest thats the first time I have witnessed it, and I couldn`t believe it. We had a Red I believe #6 Cinimoid Gel loaded in, and after we changed the bulb and was testing the light, we switched to the red, and within seconds what was red wen`t to clear, with only a bit of the red still showing in the center of the gel, to indicate that there was even red gel there.
    I am not quite sure whats going, on, as when we were adjusting the lamp screws for bulb, we got the got spot to the center of the beam, nice even light across the spot, and a really nice bright and crisp light, so it looks like it should be hotspoted correctly. But if thats the case why, is it burning out the gels like that, and that quickly.
    If anyone has any ideas of whats going on I would appreciate it, as were not having the same problem with both follow spots.
    Thanks,
    soundguy99
     
  2. techieman33

    techieman33 Well-Known Member

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    Did you mess with heat filter? I'm not sure if those lights even have one. The other thing that comes to mind is the size handle placement. Some lights have a "sweet spot" that will cook gel in a hurry. Try moving it to a different position and see what that does.
     
  3. Amiers

    Amiers Lighting Phoenix 1 Lamp at a Time

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    Does the gel burn if you move it farther away from the source.

    You can also cut a heat shield to fit the first gel frame and always have that down. If that doesn’t work double up and heat shield in the 1st and one in front of the color.

    This of course doesn’t solve the problem of why but it’s a start.

    If I had to guess you got the wrong wattage lamp in there.
     
  4. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Cinemoid hasn't been made since the 1980s, so I doubt it was that. If it was, that would explain it, as Cinemoid was never intended to take the heat of anything other than an incandescent, non-T/H source.

    Your Strong 575 uses an HMI source, same lamp as in the Altman Satellite I, I believe.

    The fixture does use a heat filter, see figure 4 in the manual: http://www.schellscenic.com/downloads/strong575.pdf .
    Item #24 in the diagram (the only color without a handle, thus it is always in the beam path). After 20+ years, not surprising it is likely shot.

    strong575boomerang.jpg

    Unlike xenon source lights, it's not a mirror or dichroic glass, looks like just a piece of heat shield. It it were me, I'd replace with a piece of Apollo Gel Shield, which I personally think is the best. Also the most expensive, and was not around when the light was made, so maybe regular heat shield would perform satisfactorily as well. If you do use the Apollo Gel Shield, make sure it's facing the correct way. One side is electrically conductive and the other side is not. Conductive side goes toward the lamp. Note that you don't have to buy a full sheet for $50-60 (MSRP $61.45). I don't remember the size of the circles of gel used, but you can probably get by with one 8"x8" cut (MSRP $12.50), maybe even a 6x6 (MSRP $9.40).

    Let us know your results.
     
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  5. JD

    JD Well-Known Member

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    I think Derek has the answer above, but a couple of other things to check:
    1) When comparing the beams of both spots with no color, do they look any different side by side?
    (Same max size, equal brightness in the center as the edges?) If not, you may have an alignment issue.
    2) Are your gels in the same positions in both color booms? Some gels/colors are more sensitive to heat and survive better when the are positioned farther from the lamp and heat shield.
    3) In general, the wider the iris, the more heat hits the gel. Since Strong uses a zoom optics system, you may find zooming out and iris-ing in gives you longer life as long as you still have acceptable brightness.
    4) Last but not least, you want to make sure you have good airflow from that front fan into the color boom.
     
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  6. soundofsparks

    soundofsparks Active Member

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    It does sound like the bench might be too peaky. Is there a lamp position that improves gel life without giving you a dark spot?
     
  7. soundguy99

    soundguy99 Member

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    Hi Guys,
    Sorry for the long, delay in replying.
    In short when I finally got a chance and opened it up, it turns out there wasen`t any gel's or gel frame in the spot for the heat shield, so thanks to
    derekleffew, and everyone else for replying, as It looks like that is the case.
    We did order some of Apollo Gel Shield unfortunately its still not here yet, so I was waiting to get it here try it before fully replying to everyone.
    Its funny our stage manager, who has been here for a long time always talked about the one spot burning gels but never looked into it.lol, the bulb was just dimmed enough, and not adjusted correctly enough for the one spot to not burn gels...lol
    I again Thank you for the replies and will reply again when I get it in and try it
    Thanks
    soundguy99
     
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  8. Kelite

    Kelite Apollo Staff Premium Member

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    Hi, soundguy99.
    We keep quite a bit of the Apollo Gel Shield in stock, as it is quite effective for a variety of applications. (Like yours) Please let us know how your fixtures respond to this fresh heat block as well as a properly bench focus. This is only so much a shield can do when a lamp is 'peaked out' and delivering a laser-beamish hot spot. :D
     
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  9. soundguy99

    soundguy99 Member

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    So Update,
    We finally got our Heat shield, and wouldn`t you know it happens to be the day before the long weekend, as well as the beginning of our dance recitals that stretch on for 2 weeks.
    That being said I did manage to at least cut them and try it out. I also put in another red gel, to try although, it was unmarked, so I am not sure if it was a Strand Cinemoid or either Rosco or Lee.
    As soon as I put the red frame into the light it burned right through it, leaving almost no color behind. The other colors seemed to be ok, but again they were not as affected before, even with out the shield.
    After taking it out, there is clearly a hole right through the center with another smaller one near the bottom.
    As I said I am not completely sure if it was a cinemoid (yes we still have/use allot of them in our building), or weather it was rosco or lee. I checked it against out swatch books and its about a cinemoid #6 or Rosco 26 for color.
    Also although the spot has a fairly consistent even wash across the spot I did see a slight hot spot that I didn`t see before, so when I get more time after our dance recitals I will check into that.
    I think my next test is to go through out gels, and cut a brand new set of gels for the spot, including a red, blue, green, Flesh, lightblue, and Frost. That way I can be sure that they are all the same Gel Mfg. and they all should work with the spot (including the dark colors). especially now with the Gel Shield is in place.
    If it then still burns through. the Dark colored Gels I then have to blame it on the fixture, either bench focus, or one of the lenses.
    As I missed my opportunity to play around with it, it will have to wait until after our dance recitals, unless some time pops up in the meantime.
    Thanks again, for all the help guys,
    I will continue to keep you posted as I experiment with this.
    Thanks,
    soundguy99
     
  10. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    An old hand can tell the difference between Cinemoid, Lee Filters, and Roscolux just by feel. Cinemoid is the thickest, and Roscolux, by comparison, has a "cello-fany" feel. If one dampens a tissue then rubs it on Lee Filters (or ApolloGel) the color will transfer onto the tissue. Not an issue, just a fact of coated rather than body-dyed color media.

    Do keep us informed, as several of us have now become emotionally involved. :)
     
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  11. Amiers

    Amiers Lighting Phoenix 1 Lamp at a Time

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    Ditto. I’m surprised the heat shield didn’t help even a little bit.

    Next you should take a video for research purpose. Maybe Apollo *cough* will give you swag for field testing heat shield with older gels vs newer gels vs whatever you use for a constant.
     
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  12. soundguy99

    soundguy99 Member

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    derekleffew, I agree spotting Cinemoid is almost a no brainer, as its very thick stiff plastic, and up in the spot light booth, and catwalks, we tend to have allot of our original Cinemoid stock which I have yet to go through.
    Even putting it in I thought it felt like a cinemoid, based on thickness and stiffness, or so I thought at the time, however after it burned up, and taking it out, it felt like it lost allot of that thickness and stiffness, which makes me question it in the first place, and since I don`t know for sure, I was reluctant to say anything one way or the other.
    One tech a while ago said something about the aliment of the lense being off, but I never did fully understand what he meant by that.
    As for the swag..lol I will be just happy if we can figure out whats going on, although from what I have been told, its been doing that for many years, and no one has looked into it enough to find the problem..lol, besides I recently talked to one of my bulb suppliers and he said its harder to find bulbs for those strong 575's anymore, much like every thing else including the MSD250's. Everything has gone to LED's now, so the benefits of finding a solution could be a bit short lived..lol
    I will keep you posted,
    Thanks,
    soudnguy99
     
  13. JohnD

    JohnD Well-Known Member Fight Leukemia

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    Perhaps at least for your three darker colors, order in some Lee High Temp. That might help. Since you have two followspots and think it may be a lens issue, swap the lenses one at a time and see if the problem follows the lens.
    Do an in depth forensic analysis of the two spots, are the serial numbers close or is one unit much older? Consider @JD suggestion about the fan, perhaps one fan is getting lazy.
     
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  14. JD

    JD Well-Known Member

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    Cinemoid never really worked on high-power folowspots. Older Troupers had a very large frame size. Many newer spots have a very small frame that is closer to (what I humorously call) the singularity! (The point where everything converges.) Note, I said "closer." It doesn't take much of an aliment error to end up with that beam focal point landing smack-dab in the color changer (boom.) Check your fans, but check your bench focus as well. The combination of Cinemoid and a high power spot doesn't bode well for long life!
    I always love the feeling of Cinemoid! It almost felt like dried Jello. (Thus the name Gel ;) ) But, covering the massive frame size of a Brute-arc is actually easier on gel. Although there's a ton of light going through it, it is disbursed with not much of a hot-spot. Even then, certain colors had a very brief life. Modern high temperature gels give us very little reason to look back at the older types, even if the "feel" is more like something you should be covering an Easter basket with.
     
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  15. soundguy99

    soundguy99 Member

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    Hey Guys, UPDATE
    Finally got done my dance and band concerts, so I have more time to mess with the spot.
    I tried putting in a rosco 23,
    now here is where it gets interesting
    After putting it in I turned on the spot, put the frame in, and messed around with it with no problems. I went over to the fly rail to restore some trims on some pipes and came back to the spot.
    With the spot at about a 4-5 foot diameter the gel had no problems, however as I increased the iris to a much large spot, the rosco 23 burnt like the Strand. I then switched to what I believe was a rosco 80 (Blue), and pretty much the same thing although there was a bit more blue left behind.
    So its making me wonder now, weather its a bench focusing issue, something miss aligned with the lenses or weather I need High temp gels.
    Strange that the iris changed how it burnt the gels.
    Any thoughts are greatly appreciated,
    Thanks,
    soundguy
     
  16. techieman33

    techieman33 Well-Known Member

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    The more the iris is closed the more heat it's absorbing. Opened up it lets more heat through to the gels.
     
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  17. JD

    JD Well-Known Member

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    Not strange a all! The wider the iris the more heat hits the gels. Maybe it's time to post a picture of one of the burnt gels. We could tell a lot from that.
     
  18. Amiers

    Amiers Lighting Phoenix 1 Lamp at a Time

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    Yes pictures!!!! And as the others said the more open you go the more heat hits the gel.
     
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  19. soundguy99

    soundguy99 Member

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    Hi Guys,
    Yes as soon as you guys said that, that does make sense, however I guess my thinking was, that if it was a hot spot in the center causing it to burn, then even with a tight iris, as long as the hotspot was in the center the gel would be still exposed to a high intensity beam at the center, therefore burning the gel, no mater how big the iris was.
    Anyways here are some pictures,
    Thanks again Guys,
    Cinemoid #6 (Possible).JPG Rosco #6 (Possible).JPG Rosco 23.JPG Rosco 80.JPG
     
  20. blueeyesdesigns

    blueeyesdesigns Member

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    This screams bench focusing issue to me.
     
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