The above Ad will no longer appear after you Sign Up for Free!

Homemade Gobos

Discussion in 'Lighting and Electrics' started by Schniapereli, Dec 16, 2006.

  1. Schniapereli

    Schniapereli Active Member

    Messages:
    334
    Likes Received:
    4
    Location:
    Provo, Utah, United States
    What is the best way to make homemade gobos. I have heard of people making them out of aluminum foil (maybe just for a 3" spot) or I have heard of people making them out of the same material as the professionals. Do you just cut at with special knife. It looks tough to cut through...

    Also, my uncle has a laser engraving machine that he uses to make trophies, ornaments, and other things. He can cut *PLEXIGLASS, and also make it different colors. Could this be used to make glass gobos? I don't know if it will be able to withstand the heat. I'm thinking if it we'd have to make a rectangular block to fit in the accessory slot, or would it still be withstandable if it were thin enough to put in the regualr gobo slot? (our ERS's are 750W Source Fours with 575W bulbs in them.)
    If that is still hot, could we put a little one in just a baby spot?
    I'm going to maybe take a little extra ornament and test it out inside the intense heat to see what would happen.
    If it could work, than that would just be freakin' awesome at our school...

    If any of you know about safely getting either the glass or metal to work well, then please grace me with your mighty wisdom.
    I just want to make sure it won't ruin anything.

    *=EDIT
     
    Last edited: Dec 16, 2006
  2. soundman

    soundman Well-Known Member

    Messages:
    1,085
    Likes Received:
    115
    Location:
    Nashville TN
    Basic gobos can be esily made out of disposable cookie sheets cut with a hobbie knife or a razor. Anythign with a lot of detail will be hard be hand, it is possible to make them using an acid bath. Technical Design Solutions for Theatre Vol 1 has a great write up of how to do it. In short you coat the gobo blanks (printers tin) with lacquer then scratch off where you want the acid to eat through.

    I would think the lazer engraver would work as long as it could cut the metal completly.
    No matter what you make the gobos out of in a source four they will get beat up by heat. After a few shows small deatil cuts will bend and be impossible to focus, so I wouldnt worry too much about heat hurting the metal. Just dont use cardboard, thats a bad idea as some other members found out.
     
  3. Schniapereli

    Schniapereli Active Member

    Messages:
    334
    Likes Received:
    4
    Location:
    Provo, Utah, United States
    The laser actually isn't strong enough to cut through metal, but it can cut through *PLEXIGLASS. I was wondering how thick *PLEXIGLASS has to be to not melt, if it can be used at all as a gobo. I probably didn't phrase that clearly...

    But, that's a cool acid process. I don't think our school would let us ever use that method though... but it's something I want to try eventually...

    I've been trying to find some good books too, so thanks for that suggestion. Our public library doesn't have a copy, but the a local college library has "Technical design solutions for theatre : the technical brief collection" by Sammler, Bronislaw J. (Bronislaw Joseph) if that is close to the same thing...

    *=EDIT
     
    Last edited: Dec 16, 2006
  4. soundman

    soundman Well-Known Member

    Messages:
    1,085
    Likes Received:
    115
    Location:
    Nashville TN
    I cant say if fiberglass would last.

    The acid might be a bit risky if you presented it as a theatre poject but it might make for a great chemesty project...

    That is the book I got the acid cutting process out of, Vol 1 page 9.
     
  5. DarSax

    DarSax Active Member

    Messages:
    606
    Likes Received:
    9
    Location:
    Bethesda MD
    I'd think the fiberglass would last. We've used fiberglass as a lighting material in the past (don't ask. don't use.) and isn't it used to like, fireproof things? o.o
     
  6. Schniapereli

    Schniapereli Active Member

    Messages:
    334
    Likes Received:
    4
    Location:
    Provo, Utah, United States
    Sorry, I was misinformed. It is plexiglass, which is transparent, and he can add colors on it too, which is why I am so eager to see if it works...

    Sorry for that mistake.
     
  7. DarSax

    DarSax Active Member

    Messages:
    606
    Likes Received:
    9
    Location:
    Bethesda MD
    Eeek--I would think that would melt in about 2 seconds, just about ruining your fixture.


    If you were using a selecon pacific, on the other hand...*sighs dreamily*
     
  8. Van

    Van CBMod CB Mods Premium Member

    Messages:
    5,779
    Likes Received:
    1,077
    Occupation:
    Project Manager, Stagecraft Industries, Inc.
    Location:
    Portland, Or.
    Plexi + Heat = 1 big mess, by the time you got your hand on some form of high temp carbonfiber re-enforced resin material to use as a gobo you'd have spent a ton more then if you bought a case of regular gobos. Sorry to say the plexi is right out, along with almost any variant thereof, eg poly-carbonate, acrylic, etc. Plastics are just too susceptible to heat and there is a ton of heat in the gate of an ERS. The acid bath method works well and is not very dangerous at all *If you follow the instructions* you can use many different forms of resist < resist is the material you coat the metal in lacquer, wax, sharpie, rubber> the acid is readily availible in most home centers < Home Depot, Lowes, etc> Concrete etcher, sold as driveway cleaner is nothing more than Muratic acid. I've used the wax method when etching blades for stage weapons. < I did the weapons for The Hobbit a few years ago and etched the Elvish script with muratic acid using parfin wax as a resist> the only difference is that you leave the printers plate in the bath a little longer so it eats all the way through the metal you want removed. If you're doing a one of a kind custom gobo the cost saving is significant if you're doing just regular breakups or leaves, go with a pre-made its a lot cheaper. a single custom gobo is going to run you $125.00 by the time you pay for shipping and everything.
     
  9. Schniapereli

    Schniapereli Active Member

    Messages:
    334
    Likes Received:
    4
    Location:
    Provo, Utah, United States
    Well then, I doubt it would work in a baby spot. Oh well. Glad I asked before I tried it out on a sample.

    I guess we'll stick with the metal gobos...
     
  10. TechiGoz

    TechiGoz Active Member

    Messages:
    109
    Likes Received:
    2
    Location:
    Adelaide, Australia & Singapore
    I know that Plexi stuff may be a slightly bad idea, so I'd stick with the metal. I've made gobo's before by simply flattening a 'coke' can (or any can). Cutting off the ends and up one side, flattening it, and cutting out your pattern with a razor, stanley knife, or what ever is handy.

    It worked for me and lasted about 2 weeks before it was F***ed. But yeah, thats all I needed it for.

    Simple. Sharp. Secure.
     
  11. highschooltech

    highschooltech Active Member

    Messages:
    183
    Likes Received:
    8
    Location:
    Orange, CA
    Recently for a concert the ligthing designer and i sat dow and made gobos out of pin tins for a really cool looking sunrise effect
     
  12. kingfisher1

    kingfisher1 Active Member

    Messages:
    377
    Likes Received:
    1
    pie tins, cookies sheet are the way to go!! i found that hair cutting scissors have a good point for detail work, (not too detailed) they dull fast, but i bet its worth it. the gobos lasted me tw entire days, with the light on full the entire time. if 48 strait hours of usage isn't enough well, that must be one long run...

    also, if you are sucessful withslightly thinner aluminum you can use these hole punch thingies. they are for paper, for kids doing crafts, but i'd think they'd punch through aluminum. only pobllem is they only come in certain shapes, bears, airplanes, trains, etc, e.g.
    http://cgi.ebay.com/BEAR-scrapbooki...ri-cutout_W0QQitemZ300055637722QQcmdZViewItem
     
  13. highschooltech

    highschooltech Active Member

    Messages:
    183
    Likes Received:
    8
    Location:
    Orange, CA
    The tins lasted for several days actually and looked pretty good compared to the other gobos we were using to emulate lightning arrays.
     
  14. Schniapereli

    Schniapereli Active Member

    Messages:
    334
    Likes Received:
    4
    Location:
    Provo, Utah, United States
    How long could the plexiglass last?

    If there were just one cue, that lasted maybe for 10 seconds (or more), where the ERS would only be used for that one effect, could we turn it on (not even necessarily at full) and then turn it off before the light starts to warm up and warp the image? About how long could that last? What about in a baby spot?

    If some backround info would help, we need a star to appear over the choir for one song, at the ending. It would just appear dramatically, then go out at the next cue in like 5 or 15 seconds. I probably couldn't even order one from my uncle in time for this concert, but I would like to know how this would work in future situations.

    Thanks

    EDIT: We would have a few extra copies of the gobo, just enough to focus it, and for some rehearsals, and some extra to be safe.

    Also, another question that I didn't want to start another thread for; What is a good brand of gloves for focusing lights, etc. I got some from walmart for $2 that had good grip, and kept my hands from burning, but then while working on a S4 PAR, they started to smoke and melt through. I borrowed some from a friend who got them from Home Depot. (cost them $20) They were durable, but weren't that thick, and I couldn't work with the fixture as much before my fingers started hurting. I am looking for some good, and relatively cheap gloves that mostly retain heat, but grip is a bonus. If anybody knows a really good kind, at some store for about $40 dollars at most, that would be kewl.
     
    Last edited: Dec 18, 2006
  15. kingfisher1

    kingfisher1 Active Member

    Messages:
    377
    Likes Received:
    1
    PIE TIN!!!!!!!!!!!!!! its easy, cheap, looks good, you can leave the light on for as long as you want, stars don't have to be detailed, or IMO they don't. anyway good luck, just be really careful, the plastic will just melt al over then place. even if it doesn't its not a risk you hould take
     
  16. Van

    Van CBMod CB Mods Premium Member

    Messages:
    5,779
    Likes Received:
    1,077
    Occupation:
    Project Manager, Stagecraft Industries, Inc.
    Location:
    Portland, Or.
    You want really sharp scissor ? go borrow a pair from the costume shop, be sure not to tell them what your doing with them, They'll realy appreciate you from then forward...:twisted:


    Stay away from the plexi. As cool as it might be, trying to use a laser cutter to do all this neat stuff, your headed for heartbreak if you try to stick plexi in a ERS Period. It simply won't handle the heat. it will melt and realease toxic Cyano-acrylate fumes < yes cynanide based fumes > when it finally catches fire.

    Put the laser cutter down and step away now, nobody gets hurt.
     
  17. Schniapereli

    Schniapereli Active Member

    Messages:
    334
    Likes Received:
    4
    Location:
    Provo, Utah, United States
    Well, now you excited me. I kind of want to put plexiglass in an old Shakespeare just to watch it burn...

    I'll stay away from that idea. I just thought it might be cool, but oh well.:p
     
  18. JRRichardson

    JRRichardson Member

    Messages:
    6
    Likes Received:
    1
    Occupation:
    Technical Manager, Theatre Royal Nelson, NZ
    Location:
    Nelson, New Zealand
    If you were using a selecon pacific, on the other hand...*sighs dreamily*[/QUOTE]

    Even then it wold still melt - despite radiating heat out of the rear, the rest of the lamp still reaches considerable temp.
     
  19. Dionysus

    Dionysus Well-Known Member

    Messages:
    1,082
    Likes Received:
    162
    Occupation:
    Technical Director
    Location:
    London, Ontario, Canada
    Im not a big fan of "pie tin" gobos, not sure what kind of pie tins your guys have but I find that the pie tin gobos (depending on fixture and duration etc) hardly worthwhile, needing to be replaced far too often.
    I usually use sheetmetal, generally scraps from job sites I've worked on (have quite a stock lol). You can get some pretty thick stuff actually, and not all of it but the stuff I've really kept is STEEL so it handles the heat much better. With the right collection of tools its easy to form into rough shapes such as stars, or what have you. More difficult of course with more distinct or clear shapes.

    At least the thinner materials including pie tin you can cut and shape with a pair of OLFA SCISSORS. Drill bits, dremel, tin snips, duct knife, electricians hole punch, uni-bit, etc... I've even made a "strange snow" gobo by hammering nails in to create rough not quite round shapes.

    And yes don't ever use plastic for something that you're going to stuff in a fixture that will get exceedingly hot. It will just melt and make toxic gasses, and make you very sorry. "Glass" gobos are made from special glass for a reason.

    99% of the time though, its just as nice to use a nice gobo from Rosco or Apollo or whoever.
     
  20. Floobydust

    Floobydust Member

    Messages:
    80
    Likes Received:
    13
    Occupation:
    Light and sound provider
    Location:
    Sacramento, California
    I've been told by others to look up a local company that makes trophies and awards because some of them have metal etching lasers that might take graphics input for their machines.
    I haven't completed the research, but was gonna try to have them cut Rosco Matte Black Cinefoil.

    Might be worth looking into.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice