gobo

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hey, i need help creating a gobo for a lighting fixture at my school by thursday. I have a basic idea of how to make it but id like some detailed instructions if anyone has any to spare. thanks
 

Kelite

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Well, it looks as though time is running short so I'll throw my hat in the ring.

Using an aluminum pie pan from the local grocery store, draw the pattern you would like to project onto the inner portion of the pan. (Leave room if possible for 1-2 more patterns if space allows.) The outer diameter of the gobo should be 3.30 inches round for an average B size gobo for S4, Strand SL, Altman Shakespeare/360. The area for the image should be 2.375 inches in the center of the gobo.
Cut the pie pan with an Exacto* knife or other hobby knife while it is resting on several layers of cardboard. Use a table too- forget doing this while it is on your lap!
Place the gobo in the pattern holder upside down and backwards for proper projection.

Good luck!
 

Radman

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Thats the same process all Apollo gobos are made by, right? ;)

I've also seen them made out of soft aluminum that comes in a long sheet rolled up... if you have any lying around the shop you could play with that.

So is it just one gobo? You may consider making a spare or two while you've got the tools and materials out, never hurts to have a backup.
 

ship

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I remember a post on stagecraft about a year ago that went into many methods including something like reverse etching. Might be a good thing to do a search for.
 

photoatdv

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May 8, 2008
Guys--
I made a couple of gobos out of a thin pie pan type thing (and will be making more) for a no-budget show. IS THERE ANY WAY THAT THEY WILL MELT OR DO ANYTHING ELSE WIERD? My director thinks they are too thin. They will be used for one 2 hour show (okay we'll say 3 hrs to be safe).
 

Grog12

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Ugh....pie pan gobo's....

They won't melt photoatdv....they won't burst into flames either..and for your show they'll work just fine.

Here's what they will do....basically turn to dust after being run for a long time. Then you have to clean that crap out of the light.
 

zac850

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How hot does the oven get? How hot does the light get?

Worst case scenario is that they burn a little and don't look as sharp. It would be hard to make the pie tin melt or do anything dangerous.
 

mbandgeek

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I'vei never thought of comparing the lights to an oven before... Makes a lot of sense.
 

Grog12

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How hot does the oven get? How hot does the light get?

Worst case scenario is that they burn a little and don't look as sharp. It would be hard to make the pie tin melt or do anything dangerous.
While I get what you're going for that's really not the best analogy.

Gobo's are subject to more focused heat/light/infrared spectrum than in an oven which operates not on direct heat but a more spreadout type heat. Put that cooking tin on a burner on your stove and turn it on to medium and then leave it for two hours. There's a reason you don't leave Jiffy Pop on the stove for very long.

All that being said...yeah for someone who doesn't know how lights work that's a good analogy.
 

mbandgeek

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You are not neccessarily putting an uncut piece of aluminum in there either. I do agree with you on the direct heat source though.
 

lieperjp

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Guys--
They will be used for one 2 hour show (okay we'll say 3 hrs to be safe).
Are they going to be on for the entire show? Throwing in a couple of cooling periods might help - example: At my high school, I had my dad laser-etch a thin sheet of aluminum with the school's logo (he's a tool and die maker.) The gobos worked well, but after about 15 min they started to burn. They were ok as long as the light was not shaken/moved/adjusted, then the brittle aluminum broke. Of course, it didn't help that he forgot to clean off the oils from the machining process...
 
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philhaney

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I've never thought of comparing the lights to an oven before... Makes a lot of sense.
I bake cupcakes in my Source Fours all the time...

Are they going to be on for the entire show?
A very important question.

And if oil of any sort is going to be a consideration, clean them with isopropyl (rubbing) alcohol before hand (and let them dry completely).
 

photoatdv

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Thanks for all the help. Yes, they would be on for the entire show.

One of the teachers at my school said he will bring some thin steel this afternoon that he thinks can be cut with a knife. If that works I will switch to that.

Now if the steel doesn't work, will the (thin) pie pan ones last for the show if the light isn't touched?
 

Grog12

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Well...let me put it to you this way.

The last time I saw a pie pan gobo used it had to be replaced after every show. It was used the entire time of a 15 minute dance piece.

As has been asked before how long will it be on?

And please god head the advice of phil and clean the steel with rubbing alchol before dropping them into the lights.
 

Grog12

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Grog--


3 hours at most
Just making sure. The whole show means different things to different people. I use gobo's throughout my whole show...doesn't mean they're on the entire time.

Just clarifying for the tired.
 

quarterfront

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For what it's worth....

I did a show recently that used about a dozen foil pan gobos. Rarely were all on at once, most would be up for 5-10 minutes at a time, usually at 100%. All were in Source-4's at 575w, pointed straight down. Show ran 8 shows a week for 2 months. When I took them out they were like new, you'd never know they'd been anywhere but sitting on my desk the whole time.

Similarly, a couple years back I had a set of 6 foil pan gobos which were very titchy shapes; they were in Source-4's, again at 575w, focused horizontally. These ran fairly steadily for about 30 minutes each before getting to cool, in the 65-85% range. 8 shows a week for about 2 months. And again, at the end of the run, no burning, no curling, no nothing.

Get the heavy aluminum cookie sheets, thick like foil turkey roasting pans are made from.
 

scottmcleod

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For what it's worth....

I did a show recently that used about a dozen foil pan gobos. Rarely were all on at once, most would be up for 5-10 minutes at a time, usually at 100%. All were in Source-4's at 575w, pointed straight down. Show ran 8 shows a week for 2 months. When I took them out they were like new, you'd never know they'd been anywhere but sitting on my desk the whole time.

Similarly, a couple years back I had a set of 6 foil pan gobos which were very titchy shapes; they were in Source-4's, again at 575w, focused horizontally. These ran fairly steadily for about 30 minutes each before getting to cool, in the 65-85% range. 8 shows a week for about 2 months. And again, at the end of the run, no burning, no curling, no nothing.

Get the heavy aluminum cookie sheets, thick like foil turkey roasting pans are made from.
Great advice. This is how pie plate gobos SHOULD work.

But looking at the whole thread... I think one of the most important things that HASN'T been mentioned yet:

... TUNE YOUR LIGHTS!

If your light doesn't have a flat field, then each hotspot on the floor is going to eat away (quickly) at your gobo. De-tuning a light (making it have a weak, halo-ey field) can also be a way of preserving your gobos, by removing the hot spot... (but ruins your output)

I've made plenty of gobos out of pie plate, coke cans, you name it. Rubbing alcohol to clean, exact-o knives, tin snips, nails, jeweler's pliers, whatever it takes to make your pattern.

Work carefully, and mind where your hands are! (We had a tech cut themselves to the bone with an exact-o in my 2nd year of university while making gobos...)
 

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