Homemade Gobos

[Schniapereli]

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

[soundman]

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.

[Schniapereli]

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

[soundman]

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.

[DarSax]

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

[Schniapereli]

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.

[DarSax]

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*

[Van]

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.

[Schniapereli]

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...

[TechiGoz]

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.